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Simple Workflows With ApprovaFlow and Stateless April 2, 2011

Posted by ActiveEngine Sensei in .Net, ActiveEngine, Approvaflow, ASP.Net, C#, JSON.Net, New Techniques, Stateless.
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This is the second in a series of posts for ApprovaFlow, an alternative to Windows Workflow written in C# and JSON.Net. Source code for this post is here.

Last time we laid out out goals for a simple workflow engine, ApprovaFlow, with the following objectives:
• Model a workflow in a clear format that is readable by both developer and business user. One set of verbiage for all parties.
•. Allow the state of a workflow to be peristed as an integer, string. Quicky fetch state of a workflow.
•. Create pre and post nprocessing methods that can enforce enforce rules or carry out actions when completing a workflow task.
•. Introduce new functionality while isolating the impact of the new changes. New components should not break old ones
•.Communicate to the client with a standard set of objects. In other words, your solution domain will not change how the user interface will gather data from the user.
•. Use one. aspx page to processes user input for any type of workflow.
•. Provide ability to roll your own customizations to the front end or backend of your application.

The fulcrum point of all we have set out to do with ApprovaFlow is a state machine that will present a state and accept answers supplied by the users. One of Sensei’s misgivings about Windows Workflow is that it is such a behemoth when all you want to implement is a state machine.
Stateless, created Nicholas Blumhardt, is a shining example of adhering to the rule of “necessary and sufficient”. By using Generics Stateless allows you to create a state machine where the State and Trigger can be represented by an integer, string double, enum – say this sounds like it fulfills our goal:

•. Allow the state of a workflow to be persisted as an integer, string. Quicky fetch state of a workflow.
Stateless constructs a state machine with the following syntax:

var statemachine =
       new StateMachine(TState currentState);

For our discussion we will create a state machine that will process a request for promotion workflow. We’ll use:

var statemachine =
       new StateMachine(string currentstate);

This could very easily take the form of

<int, int>

and will depend on your preferences. Regardless of your choice, if the current state is represent by a primitive like int or string, you can just fetch that from a database or a repository and now your state machine is loaded with the current state. Contrast that with WF where you have multiple projects and confusing nomenclature to learn. Stateless just stays out of our way.
Let’s lay out our request for promotion workflow. Here is our state machine represented in English:

Step: Request Promotion Form
  Answer => Complete
  Next Step => Manager Review

Step: Manager Review
  Answer => Deny
  Next Step => Promotion Denied
  Answer => Request Info
  Next Step => Request Promotion Form
  Answer => Approve
  Next Step => Vice President Approve

Step: Vice President Approve
  Answer => Deny
  Next Step => Promotion Denied
  Answer => Manager Justify
  Next Step => Manager Review
  Answer => Approve
  Next Step => Promoted

Step: Promotion Denied
Step: Promoted

Remember the goal Model a workflow in a clear format that is readable by both developer and business user. One set of verbiage for all parties? We are very close to achieving that goal. If we substitute “Step” with “State” and “Answer” with “Trigger”, then we have a model that matches how Stateless configures a state machine:

var statemachine = new StateMachine(startState);

//  Request Promo form states
statemachine.Configure("RequestPromotionForm")
               .Permit("Complete", "ManagerReview");

//  Manager Review states
statemachine.Configure("ManagerReview")
               .Permit("RequestInfo", "RequestPromotionForm")
               .Permit("Deny", "PromotionDenied")
               .Permit("Approve", "VicePresidentApprove");

Clearly you will not show the code to your business partners or end users, but a simple chart like this should not make anyone’s eyes glaze over:

State: Request Promotion Form
  Trigger => Complete
  Target State => Manager Review

Before we move on you may want to study the test in the file SimpleStateless.cs. Here configuring the state machine and advancing from state to state is laid out for you:

//  Request Promo form states
statemachine.Configure("RequestPromotionForm")
                    .Permit("Complete", "ManagerReview");

//  Manager Review states
statemachine.Configure("ManagerReview")
                     .Permit("RequestInfo", "RequestPromotionForm")
                     .Permit("Deny", "PromotionDenied")
                     .Permit("Approve", "VicePresidentApprove");

//  Vice President state configuration
statemachine.Configure("VicePresidentApprove")
                      .Permit("ManagerJustify", "ManagerReview")
                      .Permit("Deny", "PromotionDenied")
                      .Permit("Approve", "Promoted");

//  Tests
Assert.AreEqual(startState, statemachine.State);

//  Move to next state
statemachine.Fire("Complete");
Assert.IsTrue(statemachine.IsInState("ManagerReview"));

statemachine.Fire("Deny");
Assert.IsTrue(statemachine.IsInState("PromotionDenied"));

The next question that comes to mind is how to represent the various States, Triggers and State configurations as data. Our mission on this project is to adhere to simplicity. One way to represent a Stateless state machine is with JSON:

{WorkflowType : "RequestPromotion",
  States : [{Name : "RequestPromotionForm" ; DisplayName : "Request Promotion Form"}
    {Name : "ManagerReview", DisplayName : "Manager Review"},
    {Name : "VicePresidentApprove", DisplayName : "Vice President Approve"},
    {Name : "PromotionDenied", DisplayName : "Promotion Denied"},
    {Name : "Promoted", DisplayName : "Promoted"}
    ],
  Triggers : [{Name : "Complete", DisplayName : "Complete"},
     {Name : "Approve", DisplayName : "Approve"},
     {Name : "RequestInfo", DisplayName : "Request Info"},
     {Name : "ManagerJustify", DisplayName : "Manager Justify"},
     {Name : "Deny", DisplayName : "Deny"}
  ],
StateConfigs : [{State : "RequestPromotionForm", Trigger : "Complete", TargetState : "ManagerReview"},
     {State : "ManagerReview", Trigger : "RequestInfo", TargetState : "RequestPromotionForm"},
     {State : "ManagerReview", Trigger : "Deny", TargetState : "PromotionDenied"},
     {State : "ManagerReview", Trigger : "Approve", TargetState : "VicePresidentApprove"},
     {State : "VicePresidentApprove", Trigger : "ManagerJustify", TargetState : "ManagerApprove"},
     {State : "VicePresidentApprove", Trigger : "Deny", TargetState : "PromotionDenied"},
     {State : "VicePresidentApprove", Trigger : "Approve", TargetState : "Promoted"}
  ]
}

As you can see we are storing all States and all Triggers with their display names. This will allow you some flexibility with UI screens and reports. Each rule for transitioning a state to another is stored in the StateConfigs node. Here we are simply representing our chart that we created above as JSON.

Since we have a standard way of representing a workflow with JSON de-serializing this definition to objects is straight forward. Here are the corresponding classes that define a state machine:

public class WorkflowDefinition
{
        public string WorkflowType { get; set; }
        public List States { get; set; }
        public List Triggers { get; set; }
        public List StateConfigs { get; set; }

        public WorkflowDefinition() { }
}

public class State
{
        public string Name { get; set; }
        public string DisplayName { get; set; }
}

public class Trigger
{
        public string Name { get; set; }
        public string DisplayName { get; set; }

        public Trigger() { }
}
public class StateConfig
{
        public string State { get; set; }
        public string Trigger { get; set; }
        public string TargetState { get; set; }

        public StateConfig() { }
}

We’ll close out this post with an example that will de-serialize our state machine definition and allow us to respond to the triggers that we supply. Basically it will be a rudimentary workflow. RequestionPromotion.cs will be the workflow processor. The method Configure is where we will perform the de-serialization, and the process is quite straight forward:

  1. Deserialize the States
  2. Deserialize the Triggers
  3. Deserialize the StateConfigs that contain the transitions from state to state
  4. For every StateConfig, configure the state machine.

Here’s the code:

public void Configure()
{
    Enforce.That((string.IsNullOrEmpty(source) == false),
                            "RequestPromotion.Configure - source is null");

    string json = GetJson(source);

    var workflowDefintion = JsonConvert.DeserializeObject(json);

    Enforce.That((string.IsNullOrEmpty(startState) == false),
                            "RequestPromotion.Configure - startStep is null");

    this.stateMachine = new StateMachine(startState);

    //  Get a distinct list of states with a trigger from state configuration
    //  "State => Trigger => TargetState
    var states = workflowDefintion.StateConfigs.AsQueryable()
                                    .Select(x => x.State)
                                    .Distinct()
                                    .Select(x => x)
                                    .ToList();

    //  Assing triggers to states
    states.ForEach(state =>
    {
        var triggers = workflowDefintion.StateConfigs.AsQueryable()
                                   .Where(config => config.State == state)
                                   .Select(config => new { Trigger = config.Trigger, TargeState = config.TargetState })
                                   .ToList();

        triggers.ForEach(trig =>
        {
            this.stateMachine.Configure(state).Permit(trig.Trigger, trig.TargeState);
        });
    });
}

And we advance the workflow with this method:

public void ProgressToNextState(string trigger)
{
Enforce.That((string.IsNullOrEmpty(trigger) == false),
"RequestPromotion.ProgressToNextState – trigger is null");

this.stateMachine.Fire(trigger);
}

The class RequestPromotionTests.cs illustrates how this works.

We we have seen how we can fulfill the objectives laid out for ApprovaFlow and have covered a significant part of the functionality that Stateless will provide for our workflow engine.   Here is the source code.

ApprovaFlow – A Proof of Concept March 25, 2011

Posted by ActiveEngine Sensei in .Net, .Net Development, ActiveEngine, Approvaflow, ASP.Net, C#, JSON.Net, LINQ, New Techniques, Open Source.
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Like Tolkien, Sensei wants to create the landscapes, cultures and languages before he writes his next epic. You can be the judge whether the work is a series of sketches and notes like the Silmarillion or cohesive, compelling story that you want read again and again. As a bonus Sensei will deliver working software that hopefully will be of use to you.  (Photo credit – utnapistim).

The epic will be called ApprovaFlow. ApprovaFlow is a framework / process / methodology that allows you to create workflow applications that are easy to deploy and are configurable. With ApprovaFlow Sensei hopes to demonstrate how to readily encorporate the inevitable changes that your users will ask of you. Deliver changes effortlessly and without groans. Cast off the chains inconvenient builds and focus on creating solutions that stay out of the users way.

Ok. Managent wants bullet points so here are our goals for ApprovaFlow:

• Model a workflow in a clear format that is readable by both developer and business user. One set of verbiage for all parties.
•. Allow the state of a workflow to be peristed as an integer, string. Quicky fetch state of a workflow.
•. Create pre and post nprocessing methods that can enforce enforce rules or carry out actions when completing a workflow task.
•. Introduce new functionality while isolating the impact of the new changes. New components should not break old ones
•.Communicate to the client with a standard set of objects. In other words, your solution domain will not change how the user interface will gather data from the user.
•. Use one. aspx page to processes user input for any type of workflow.
•. Provide ability to roll your own customizations to the front end or backend of your application.

There it is. These goals will probably take us a good amount of time to review and implement. Is it worth it? Hell yeah. We’ll end up with one simple project instead of a bloated framework where it takes forever to find anything. A nice by product will be that you can spend more time thinking about how to solve your users problems rather than trying to figure out a monsterous framework that requires a huge investment of energy and time learning how to get simple things done.

DataTablePager Now Has Multi-Column Sort Capability For DataTables.Net February 9, 2011

Posted by ActiveEngine Sensei in .Net, ActiveEngine, Ajax, ASP.Net, C#, DataTables.Net, jQuery.
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21 comments

Some gifts just keep on giving, and many times things can just take on a momentum that grow beyond your expectation.  Bob Sherwood wrote to Sensei and pointed out that DataTables.net supports multiple column sorting.  All you do is hold down the shift key and click on any second or third column and DataTables will add that column to sort criteria.  “Well, how come it doesn’t work with the server side solution?”  Talk about the sound of one hand clapping.  How about that for a flub!  Sensei didn’t think of that!  Then panic set in – would this introduce new complexity to the DataTablePager solution, making it too difficult to maintain a clean implementation?  After some long thought it seemed that a solution could be neatly added.  Before reading, you should download the latest code to follow along.

How DataTables.Net Communicates Which Columns Are Involved in a Sort

If you recall, DataTables.Net uses a structure called aoData to communicate to the server what columns are needed, the page size, and whether a column is a data element or a client side custom column.  We covered that in the last DataTablePager post.  aoData also has a convention for sorting:

bSortColumn_X=ColumnPosition

In our example we are working with the following columns:

,Name,Agent,Center,,CenterId,DealAmount

where column 0 is a custom client side column, column 1 is Name (a mere data column), column 2 is Center (another data column), column 3 is a custom client side column, and the remaining columns are just data columns.

If we are sorting just by Name, then aoData will contain the following:

bSortColumn_0=1

When we wish to sort by Center, then by Name we get the following in aoData”

bSortColumn_0=2

bSortColumn_1=1

In other words, the first column we want to sort by is in position 2 (Center) and the second column(Name) is in position 1.  We’ll want to record this some where so that we can pass this to our order routine.  aoData passes all column information to us on the server, but we’ll have to parse through the columns and check to see if one or many of the columns is actually involved in a sort request and as we do we’ll need to preserve the order of that column of data in the sort.

SearchAndSortable Class to the Rescue

You’ll recall that we have a class called SearchAndSortable that defines how the column is used by the client.  Since we iterate over all the columns in aoData it makes sense that we should take this opportunity to see if any column is involved in a sort and store that information in SearchAndSortable as well.  The new code for the class looks like this:

public class SearchAndSortable
    {
        public string Name { get; set; }
        public int ColumnIndex { get; set; }
        public bool IsSearchable { get; set; }
        public bool IsSortable { get; set; }
        public PropertyInfo Property{ get; set; }
        public int SortOrder { get; set; }
        public bool IsCurrentlySorted { get; set; }
        public string SortDirection { get; set; }

        public SearchAndSortable(string name, int columnIndex, bool isSearchable,
                                bool isSortable)
        {
            this.Name = name;
            this.ColumnIndex = columnIndex;
            this.IsSearchable = isSearchable;
            this.IsSortable = IsSortable;
        }

        public SearchAndSortable() : this(string.Empty, 0, true, true) { }
    }

There are 3 new additions:

IsCurrentlySorted – is this column included in the sort request.

SortDirection – “asc” or “desc” for ascending and descending.

SortOrder – the order of the column in the sort request.  Is it the first or second column in a multicolumn sort.

As we walk through the column definitions, we’ll look to see if each column is involved in a sort and record what direction – ascending or descending – is required. From our previous post you’ll remember that the method PrepAOData is where we parse our column definitions. Here is the new code:

//  Sort columns
this.sortKeyPrefix = aoDataList.Where(x => x.Name.StartsWith(INDIVIDUAL_SORT_KEY_PREFIX))
                                            .Select(x => x.Value)
                                            .ToList();

//  Column list
var cols = aoDataList.Where(x => x.Name == "sColumns"
                                            & string.IsNullOrEmpty(x.Value) == false)
                                     .SingleOrDefault();

if(cols == null)
{
  this.columns = new List();
}
else
{
  this.columns = cols.Value
                       .Split(',')
                       .ToList();
}

//  What column is searchable and / or sortable
//  What properties from T is identified by the columns
var properties = typeof(T).GetProperties();
int i = 0;

//  Search and store all properties from T
this.columns.ForEach(col =>
{
  if (string.IsNullOrEmpty(col) == false)
  {
    var searchable = new SearchAndSortable(col, i, false, false);
    var searchItem = aoDataList.Where(x => x.Name == BSEARCHABLE + i.ToString())
                                     .ToList();
    searchable.IsSearchable = (searchItem[0].Value == "False") ? false : true;
    searchable.Property = properties.Where(x => x.Name == col)
                                                    .SingleOrDefault();

    searchAndSortables.Add(searchable);
  }

  i++;
});

//  Sort
searchAndSortables.ForEach(sortable => {
  var sort = aoDataList.Where(x => x.Name == BSORTABLE + sortable.ColumnIndex.ToString())
                                            .ToList();
  sortable.IsSortable = (sort[0].Value == "False") ? false : true;
                sortable.SortOrder = -1;

  //  Is this item amongst currently sorted columns?
  int order = 0;
  this.sortKeyPrefix.ForEach(keyPrefix => {
    if (sortable.ColumnIndex == Convert.ToInt32(keyPrefix))
    {
      sortable.IsCurrentlySorted = true;

      //  Is this the primary sort column or secondary?
      sortable.SortOrder = order;

     //  Ascending or Descending?
     var ascDesc = aoDataList.Where(x => x.Name == "sSortDir_" + order)
                                                    .SingleOrDefault();
     if(ascDesc != null)
     {
       sortable.SortDirection = ascDesc.Value;
     }
   }

   order++;
 });
});

To sum up, we’ll traverse all of the columns listed in sColumns. For each column we’ll grab the PorpertyInfo from our underlying object of type T. This gives only those properties that will be displayed in the grid on the client. If the column is marked as searchable, we indicate that by setting the IsSearchable property on the SearchAndSortable class.  This happens starting at line 28 through 43.

Next we need to determine what we can sort, and will traverse the new list of SearchAndSortables we created. DataTables will tell us what if the column can be sorted by with following convention:

bSortable_ColNumber = True

So if the column Center were to be “sortable” aoData would contain:

bSortable_1 = True

We record the sortable state as shown on line 49 in the code listing.

Now that we know whether we can sort on this column, we have to look through the sort request and see if the column is actually involved in a sort.  We do that by looking at what DataTables.Net sent to us from the client.  Again the convention is to send bSortColumn_0=1 to indicate that the first column for the sort in the second item listed in sColumns property.  aoData will contain many bSortColum’s so we’ll walk through each one and record the order that column should take in the sort.  That occurs at line 55 where we match the column index with the bSortColumn_x value.

We’ll also determine what the sort direction – ascending or descending – should be.  At line 63 we get the direction of the sort and record this value in the SearchAndSortable.

When the method PrepAOData is completed, we have a complete map of all columns and what columns are being sorted, as well as their respective sort direction.  All of this was sent to us from the client and we are storing this configuration for later use.

Performing the Sort

(Home stretch so play the song!!)

If you can picture what we have so far we just basically created a collection of column names, their respective PropertyInfo’s and have recorded which of these properties are involved in a sort.  At this stage we should be able to query this collection and get back those properties and the order that the sort applies.

You may already be aware that you can have a compound sort statement in LINQ with the following statement:

var sortedCustomers = customer.OrderBy(x => x.LastName)
                                           .ThenBy(x => x.FirstName);

The trick is to run through all the properties and create that compound statement. Remember when we recorded the position of the sort as an integer? This makes it easy for us to sort out the messy scenarios where the second column is the first column of a sort. SearchAndSortable.SortOrder takes care of this for us. Just get the data order by SortOrder in descending order and you’re good to go. So that code would look like the following:

var sorted = this.searchAndSortables.Where(x => x.IsCurrentlySorted == true)
                                     .OrderBy(x => x.SortOrder)
                                     .ToList();

sorted.ForEach(sort => {
             records = records.OrderBy(sort.Name, sort.SortDirection,
             (sort.SortOrder == 0) ? true : false);
});

On line 6 in the code above we are calling our extension method OrderBy in Extensions.cs. We pass the property name, the sort direction, and whether this is the first column of the sort. This last piece is important as it will create either “OrderBy” or the “ThenBy” for us. When it’s the first column, you guessed it we get “OrderBy”. Sensei found this magic on a StackOverflow post by Marc Gravell and others.

Here is the entire method ApplySort from DataTablePager.cs, and note how we still check for the initial display of the data grid and default to the first column that is sortable.

private IQueryable ApplySort(IQueryable records)
{
  var sorted = this.searchAndSortables.Where(x => x.IsCurrentlySorted == true)
                                                .OrderBy(x => x.SortOrder)
                                                .ToList();

  //  Are we at initialization of grid with no column selected?
  if (sorted.Count == 0)
  {
    string firstSortColumn = this.sortKeyPrefix.First();
    int firstColumn = int.Parse(firstSortColumn);

    string sortDirection = "asc";
    sortDirection = this.aoDataList.Where(x => x.Name == INDIVIDUAL_SORT_DIRECTION_KEY_PREFIX +                                                                    "0")
                                                    .Single()
                                                    .Value
                                                    .ToLower();

    if (string.IsNullOrEmpty(sortDirection))
    {
      sortDirection = "asc";
    }

    //  Initial display will set order to first column - column 0
    //  When column 0 is not sortable, find first column that is
    var sortable = this.searchAndSortables.Where(x => x.ColumnIndex == firstColumn)
                                                        .SingleOrDefault();
    if (sortable == null)
    {
      sortable = this.searchAndSortables.First(x => x.IsSortable);
    }

    return records.OrderBy(sortable.Name, sortDirection, true);
  }
  else
  {
      //  Traverse all columns selected for sort
      sorted.ForEach(sort => {
                             records = records.OrderBy(sort.Name, sort.SortDirection,
                            (sort.SortOrder == 0) ? true : false);
      });

    return records;
  }
}

It’s All in the Setup

Test it out. Hold down the shift key and select a second column and WHAMO – multiple column sorts! Hold down the shift key and click the same column twice and KAH-BLAMO multiple column sort with descending order on the second column!!!

The really cool thing is that our process on the server is being directed by DataTables.net on the client.  And even awseomer is that you have zero configuration on the server.  Most awesome-est is that this will work with all of your domain objects, because we have used generics we can apply this to any class in our domain.  So what are you doing to do with all that time you just got back?

Dynamically Select Columns with Server-Side Paging and Datatables.Net January 14, 2011

Posted by ActiveEngine Sensei in .Net, ActiveEngine, Ajax, ASP.Net, DataTables.Net, jQuery, JSON.Net, New Techniques, Problem Solving.
Tags: , , , , , ,
30 comments

Source code has been yet again updated!! Read about the changes in DataTablePager Now Has Multi-Column Sort Capability For DataTables.Net If you are new to DataTables.Net and Sensei’s paging solution and want to detailed study of how it works, work through this post first, then get the latest edition.  Note, code links in this post are to the first version.

The last episode of server-side paging with DataTablerPager for DataTables.Net we reviewed the basics of a server-side solution that paged records and returned results in the multiples as specified by DataTables.Net.  You will want to have read that post before preceding here.  The older version of the source is included in that post as well as this will help get you acclimated.  The following capabilities were reviewed:

  • The solution used generics and could work with any collection of IQueryable.  In short any of your classes from you domain solution  could be used.
  • Filtering capability across all properties was provided.  This included partial word matching, regardless of case.
  • Ordering of result set was in response to the column clicked on the client’s DataTables grid.

DataTablePager Enhancements

This past month Sensei has added new capabilities to the DataTablePager class that makes it an even better fit for use with DataTables.Net.  The new features are:

  • Dynamically select the columns from the properties of your class based on the column definitions supplied by DataTables.Net!!!
  • Exclude columns from sort or search based on configuration by DataTables.Net
  • Mix columns from your class properties with client-side only column definitions; e.g. create a column with <a href>’s that do not interfere with filtering, sorting, or other processing.

Before we jump into the nitty-gritty details let’s review how DataTables.Net allows you to control a column’s interaction with a data grid.  Grab the new source code to best follow along.

DataTables.Net Column Definition

You would think that there would be quite a few steps to keep your server-side data paging solution in concert with a client side implementation, and that would mean customization for each page.   DataTables.Net provides you with fine control over what your columns will do once displayed in a data grid.  Great, but does that mean a lot of configuration on the server side of the equation?  As well soon see, no, it doesn’t.  What is done on the client for configuration will be that you need to do.

The structure aoColumnDefs is the convention we use for column configuration.  From the DataTables.Net site:

aoColumnDefs: This array allows you to target a specific column, multiple columns, or all columns, using the aTargets property of each object in the array (please note that aoColumnDefs was introduced in DataTables 1.7). This allows great flexibility when creating tables, as the aoColumnDefs arrays can be of any length, targeting the columns you specifically want. The aTargets property is an array to target one of many columns and each element in it can be:

  • a string – class name will be matched on the TH for the column
  • 0 or a positive integer – column index counting from the left
  • a negative integer – column index counting from the right
  • the string “_all” – all columns (i.e. assign a default)

So in order for you to include columns in a sort you configure in this manner:

/* Using aoColumnDefs */
$(document).ready(function() {
	$('#example').dataTable( {
		"aoColumnDefs": [
			{ "bSortable": false, "aTargets": [ 0 ] }
		] } );
} );

} );

In other words we are defining that the first column – column 0 – will not be included in the sorting operations.  When you review the columns options you’ll see you have options for applying css classes to multiple columns, can include a column in filtering, can supply custom rendering of a column, and much more.

In the example that we’ll use for the rest of the post we are going to provide the following capability for a data grid:

  1. The first column – column 0 – will be an action column with a hyperlink, and we will want to exclude it form sort and filtering functions.
  2. Only display a subset of the properties from a class.  Each of these columns should be sortable and filterable.
  3. Maintain the ability to chunk the result set in the multiples specified by DataTables.Net; that is, multiples of 10, 50, and 100.

Here is the configuration from the aspx page SpecifyColumns.aspx:

"aoColumnDefs" : [
   {"fnRender" : function(oObj){
      return "<a href="&quot;center.aspx?centerid=&quot;">Edit</a>";
   },
     "bSortable" : false,
     "aTargets" : [0]},
   {"sName" : "Name",
     "bSearchable" : true,
     "aTargets": [1]},
   {"sName" : "Agent",
    "bSearchable" : true,
    "bSortable" : true,
    "aTargets" : [2]
   },
   {"sName" : "Center", "aTargets": [3]},
   {"fnRender" : function(oObj){
            return "2nd Action List";
         },
     "bSortable" : false,
     "aTargets" : [4]},
   {"sName" : "CenterId", "bVisible" : false, "aTargets" : [5]},
   {"sName" : "DealAmount", "aTargets" : [6]}
]
  1. Column 0 is our custom column – do not sort or search on this content.  Look at oObj.aData[4] – this is a column that we’ll return but not display.  It’s referred so by the position in the data array that DataTables.Net expects back from the server.
  2. Columns 1 – 3 are data and can be sorted.  Note the use of “sName”.  This will be included in a named column list that corresponds to the source property from our class.  This will be very important later on for us, as it allows us to query our data and return it in any order to DataTables.Net.  DataTables will figure out what to do with it before it renders.
  3. Threw in another custom column.  Again, no sort or search, but we’ll see how this affects the server side implementation later on.  Hint – there’s no sName used here.
  4. Another data column.

To recap, we want to be able to define what data we need to display and how we want to interact with that data by only instructing DataTables.Net what to do.  We’re going to be lazy, and not do anything else – the class DataTablePager will respond to the instructions that DataTables.Net supplies, and that’s it.  We’ll review how to do this next.  Sensei thinks you’ll really dig it.

DataTablePager Class Handles your Client Side Requests

If you recall, DataTables.Net communicates to the server via the structure aoData.  Here is the summary of the parameters.  One additional parameter that we’ll need to parse is the sColumns parameter, and it will contain the names and order of the columns that DataTables.Net is rendering.  For our example, we’ll get the following list of columns if we were to debug on the server:

,Name,Agent,Center,,CenterId,DealAmount

These are all the columns we named with sName, plus a place holder for those custom columns that not found in our class.  This has several implications.  For one, it will mean that we will no longer be able to simply use reflection to get at our properties, filter them and send them back down to the client.  The client is now expecting an array where each row will have 7 things, 5 of which are named and two place holders for items that the client wants to reserve for itself.  Hence the convention of passing an empty item in the delimited string as shown above.

It will also mean that we’ll have to separate the columns that we can filter or sort.  Again this is the reason for leaving the custom column names blank.  In other words, we’ll have to keep track of the items that we can search and sort.  We’ll do this with a class called SearchAndSortable:

public class SearchAndSortable
    {
        public string Name { get; set; }
        public int ColumnIndex { get; set; }
        public bool IsSearchable { get; set; }
        public bool IsSortable { get; set; }
        public PropertyInfo Property{ get; set; }

        public SearchAndSortable(string name, int columnIndex, bool isSearchable, bool isSortable)
        {
            this.Name = name;
            this.ColumnIndex = columnIndex;
            this.IsSearchable = isSearchable;
            this.IsSortable = IsSortable;
        }

        public SearchAndSortable() : this(string.Empty, 0, true, true) { }
    }

This will summarize what we’re doing with our properties.   The property ColumnIndex will record the position in sColumn where our column occurs.  Since we’ll need access to the actual properties themselves we’ll store these in the SearchAndSortable as well so that we can reduce the number of calls that use reflection. DataTablePager uses a List of SortAndSearchables to track what’s going on.  We fill this list in the method PrepAOData()

//  What column is searchable and / or sortable
            //  What properties from T is identified by the columns
            var properties = typeof(T).GetProperties();
            int i = 0;

            //  Search and store all properties from T
            this.columns.ForEach(col =>
            {
                if (string.IsNullOrEmpty(col) == false)
                {
                    var searchable = new SearchAndSortable(col, i, false, false);
                    var searchItem = aoDataList.Where(x => x.Name == BSEARCHABLE + i.ToString())
                                     .ToList();
                    searchable.IsSearchable = (searchItem[0].Value == "False") ? false : true;
                    searchable.Property = properties.Where(x => x.Name == col)
                                                    .SingleOrDefault();

                    searchAndSortables.Add(searchable);
                }

                i++;
            });

            //  Sort
            searchAndSortables.ForEach(sortable => {
                var sort = aoDataList.Where(x => x.Name == BSORTABLE + sortable.ColumnIndex.ToString())
                                            .ToList();
                sortable.IsSortable = (sort[0].Value == "False") ? false : true;
            });

We’ll get the properties from our class. Next we’ll traverse the columns and match the property names with the names of the columns. When there is a match, we need to query aoData and get the column search and sort definitions based on the ordinal position of the column in the sColumns variable. DataTables.Net convention for communicating this is the form of:

bSortable_ + column index => “bSortable_1” or “bSearchable_2”

We take care of that with this line of code:

var searchItem = aoDataList.Where(x => x.Name == BSEARCHABLE +
                                     i.ToString())
                                     .ToList();
searchable.IsSearchable = (searchItem[0].Value == "False") ? false : true;

Now we go through the list of properties again but this time determine if we should sort any of the columns. That happens in the section //Sort. In the end we have a list of properties that corresponds with the columns DataTables.Net has requested, and we have defined if the property can be search (filtered) or sorted.

For filtering DataTablePager recall that we use the method GenericSearchFilter().  The only alteration here is that we only will add the properties to our query that are defined as searcable:

//  Create a list of searchable properties
            var filterProperties = this.searchAndSortables.Where(x =>
                                        x.IsSearchable)
                                          .Select(x => x.Property)
                                          .ToList();

The rest of the method is unaltered from the prior version. Pretty cool!! Again, we’ll only get the properties that we declared as legal for filtering. We’ve also eliminated any chance of mixing a custom column in with our properties because we did not supply an sName in our configuration.

The method ApplySort() required one change. On the initial load of DataTable.Net, the client will pass up the request to sort on column 0 even though you may have excluded it. When that is the case, we’ll just look for the first column that is sortable and order by that column.

//  Initial display will set order to first column - column 0
//  When column 0 is not sortable, find first column that is
var sortable = this.searchAndSortables.Where(x => x.ColumnIndex ==
                                         firstColumn)
                              .SingleOrDefault();
if(sortable == null)
{
   sortable = this.searchAndSortables.First(x => x.IsSortable);
}

return records.OrderBy(sortable.Name, sortDirection, true);

After we have filtered and sorted the data set we can finally select the only those properties that we want to send to the client.  Recall that we have parsed a variable sColumns that tells what columns are expected.  We’ll pass these names onto extension method PropertiesToList().  This method will only serialize the property if the column is include, and since we have already paired down our data set as a result of our query and paging, there is very little performance impact.  Here is the new PropertiesToList method:

public static ListPropertiesToList(this T obj, List propertyNames)
{
   var propertyList = new List();
   var properties = typeof(T).GetProperties();
   var props = new List();

   //  Find all "" in propertyNames and insert empty value into list at
   //  corresponding position
   var blankIndexes = new List();
   int i = 0;

   //  Select and order filterProperties.  Record index position where there is
   //  no property
   propertyNames.ForEach(name =>
   {
      var property = properties.Where(prop => prop.Name == name.Trim())
         .SingleOrDefault();

      if(property == null)
      {
         blankIndexes.Add(new NameValuePair(name, i));
      }
      else
      {
         props.Add(properties.Where(prop => prop.Name == name.Trim())
                                    .SingleOrDefault());
      }
      i++;
   });

   propertyList = props.Select(prop => (prop.GetValue(obj, new object[0]) ?? string.Empty).ToString())
                                        .ToList();

   //  Add "" to List as client expects blank value in array
   blankIndexes.ForEach(index =>; {
      propertyList.Insert(index.Value, string.Empty);
   });

   return propertyList;
}

You might ask why not just pass in the list of SearchAndSortTable and avoid using reflection again. You could, but remember at this point we have reduced the number of items to the page size of 10, 50 or 100 rows, so your reflection calls will not have that great an impact. Also you should consider whether you want to simply have a function that will select only those properties that you need. Using SearchAndSortable would narrow the scope of utility, as you can use this method in other areas other than prepping data for DataTables.Net.

Now It’s Your Turn

That’s it.  Play with the page named SpecifyColumns.aspx.  You should be able to add and remove columns in the DataTable.Net configuration and they will just work.  This will mean, however, that you’ll have to always define your columns in your aspx page.  But since we worked really hard the first time around, DataTablePager will still be able to create paged data sets for any class in your domain.

Source code is here.  Enjoy.

How to Embed Grooveshark Widgets in WordPress.com January 4, 2011

Posted by ActiveEngine Sensei in ActiveEngine, Problem Solving.
Tags:
49 comments

Readers of this blog will not that there many references to music, music that rocks. To share a secret, Sensei was once a band nerd. A drummer band nerd, the one that you never could sit next to during a test because Sensei could not stop tapping rudiments. To this day he is still shunned from meetings. Not a bad strategy when you want to leave and get things done!

Prior to 2010 ClearSpring made a widget that allowed you to insert a Grooveshark playlist or single song into a post. Here are a few different samples.  In 2010 they announced that they would no longer support the widget platform, and, well, the widgets would be going away.

Come 1/1/2011 all the songs on this blog were gone.  “What the …” you say.  “How come I hear music playing now?”  Well credit goes to Panos at WordPress Tips, who has a great post on how to use gigya code to embed flash objects into your posts.

Here are the steps you need to perform:

  1. Create your Grooveshark song widget.  This can be a playlist or a single song.  For our example we’ll do one song.
  2. Once you have saved your song, select “Get Embedded Code”.  Note that the url will read something similar to this:http://widgets.grooveshark.com/finished?widgetid=23332943The parameter widgetid is the code you’ll want to copy, as this links you to your song.
  3. Past the following code into your post:

Don’t forget to change the widgetID code to match the code of your widget.  You should see the result below:

For a playlist change your gigya code to match the following:

How to Create Server-Side Paging for DataTables.Net with ASP.Net December 19, 2010

Posted by ActiveEngine Sensei in .Net, ActiveEngine, C#, DataTables.Net, Fluent, jQuery, New Techniques, Open Source, Problem Solving, Tutorial.
Tags: , , , , , , ,
22 comments

Source code has been updated!! Read about the changes in Dynamically Select Columns with Server-Side Paging and Datatables.Net If you are new to DataTables.Net and Sensei’s paging solution and want to detailed study of how it works, work through this post first, then get the latest edition.  Note, code links in this post are to the first version.

A central theme for 2010 has been fluency, or the continual practice of certain methods to such a degree that your performance improves and you produce increasingly polished, effective solutions.  For software development this has meant tools to save time and increase quality.  It also means keeping an eye toward making the users of your solutions more efficient as well.  In the spirit of “fluent solutions”, Sensei will end the year with a post that examines how to create a data paging solution for the jQuery data grid plug-in DataTables.Net.

DataTables can turn a HTML table into a fully functional data grid like the one offered by Telerik.  This plug-in offers client side sorting, filtering/ search,  as well as support for server-side processing processing of data.  It is an extremely feature rich tool created by Allan Jardine, and is itself worthy of a series of posts.  For this post on data paging Sensei recommends that you read through these examples to get an idea of what the data paging service needs to achieve.

Let’s get started with the goals we need to achieve when providing server-side data paging support:

  • Send data to client in the multiples or “chunks” that the client requests, and respond when the size of the sets requested is changed by the user.
  • Re-order the data set if the user clicks on a column heading.  Honor the data set size when returning the data.
  • Filter across all columns of data based on user input.  Implement this as partial matches, and again, honor the data set size.

Remember this is about flexibility, so we have the additional goals of:

  • Create a solution that can be reused.
  • Provide a mechanism to accommodate any type of .Net class using generics.

Essentially we want to be able to write code like so:

var tenants = tenantRepository.GetAll();
var dataTablePager = new DataTablePager();
var returnDataSet = dataTablePager.Filter(requestParms, tenants);

Before we proceed, Sensei wants to acknowledge those really smart people whose ideas contributed to this solution:

Zack Owens – jQuery DataTables Plugin Meets C#

Jeff Morris – Using Datatables.net JQuery Plug-in with WCF Services

Dave Ward – ASMX ScriptService mistake – Invalid JSON primitive

You may want to download the source before reading the rest of this post.

Communicating with DataTables

DataTables uses the following parameters when processing server-side data:

Sent to the server:

Type Name Info
int iDisplayStart Display start point
int iDisplayLength Number of records to display
int iColumns Number of columns being displayed (useful for getting individual column search info)
string sSearch Global search field
boolean bEscapeRegex Global search is regex or not
boolean bSortable_(int) Indicator for if a column is flagged as sortable or not on the client-side
boolean bSearchable_(int) Indicator for if a column is flagged as searchable or not on the client-side
string sSearch_(int) Individual column filter
boolean bEscapeRegex_(int) Individual column filter is regex or not
int iSortingCols Number of columns to sort on
int iSortCol_(int) Column being sorted on (you will need to decode this number for your database)
string sSortDir_(int) Direction to be sorted – “desc” or “asc”. Note that the prefix for this variable is wrong in 1.5.x where iSortDir_(int) was used)
string sEcho Information for DataTables to use for rendering

Reply from the server

In reply to each request for information that DataTables makes to the server, it expects to get a well formed JSON object with the following parameters.

Type Name Info
int iTotalRecords Total records, before filtering (i.e. the total number of records in the database)
int iTotalDisplayRecords Total records, after filtering (i.e. the total number of records after filtering has been applied – not just the number of records being returned in this result set)
string sEcho An unaltered copy of sEcho sent from the client side. This parameter will change with each draw (it is basically a draw count) – so it is important that this is implemented. Note that it strongly recommended for security reasons that you ‘cast’ this parameter to an integer in order to prevent Cross Site Scripting (XSS) attacks.
string sColumns Optional – this is a string of column names, comma separated (used in combination with sName) which will allow DataTables to reorder data on the client-side if required for display
array array mixed aaData The data in a 2D array

The data sent back is in the following form depicted below. Note that aaData is merely an array of strings – there is no column information. This will present a challenge in that you will not be able to simply serialize a collection and pass back the results.

{
    "sEcho": 3,
    "iTotalRecords": 57,
    "iTotalDisplayRecords": 57,
    "aaData": [
        [
            "Gecko",
            "Firefox 1.0",
            "Win 98+ / OSX.2+",
            "1.7",
            "A"
        ],
        [
            "Gecko",
            "Firefox 1.5",
            "Win 98+ / OSX.2+",
            "1.8",
            "A"
        ],
        ...
    ]
}

As you may be aware, if you wish to use ASP.Net web services to serialize JSON you must POST to the service and instruct it to interpret your parameters as JSON. DataTables will POST variables as value pairs and this won’t work for us when POSTing to a web service. We’ll have to translate the variables to a usable format. Luckily DataTables allows us to intervene with the following code, where we create a JSON string by serializing a structure called aoData:

"fnServerData": function ( sSource, aoData, fnCallback ) {

		        	var jsonAOData = JSON.stringify(aoData);

			        $.ajax( {
                                        contentType: "application/json; charset=utf-8",
				        type: "POST",
				        url: sSource,
				        data: "{jsonAOData : '" + jsonAOData + "'}",
				        success: function(msg){
				            fnCallback(JSON.parse(msg.d));
				        },
				        error: function(XMLHttpRequest, textStatus, errorThrown) {
                            alert(XMLHttpRequest.status);
                            alert(XMLHttpRequest.responseText);

                        }
			        });

Our web service can now de-serialize aoData and parse the appropriate parameters. This gives us important items such as how many records to display, what columns to sort on, and what search terms should be applied in a filter.

DataTablePager Class

DataTablePager.cs is the work horse of our solution.  It will sort, filter and order our data, and as an extra, serialize the results in format required by aaData.  Here’s the constructor:

public DataTablePager(string jsonAOData, IQueryable queryable)
        {
            this.queryable = queryable;
            this.type = typeof(T);
            this.properties = this.type.GetProperties(BindingFlags.Public | BindingFlags.Instance);
            this.aoDataList = new List>();
            this.sortKeyPrefix = new List();

            PrepAOData(jsonAOData);
        }

The parameter jsonAOData is the JSON string that contains the variables iDisplayStart, iDisplayLength, etc.  These will be parsed by the method PrepAOData.  The parameter queryable is the collection of records that will be filtered and parsed into JSON format required by DataTables.

The method Filter() coordinates all of the work.  It’s pretty simple what we want to do:  filter our data based on each column containing the search term, sort the result, then pull out the number of records we need to include in the page, and finally convert the collection into the format DataTables understands.

public FormattedList Filter()
        {
            var formattedList = new FormattedList();

            //  What are the columns in the data set
            formattedList.Import(this.properties.Select(x => x.Name + ",")
                                                 .ToArray());

            //  Return same sEcho that was posted.  Prevents XSS attacks.
            formattedList.sEcho = this.echo;

            //  Return count of all records
            formattedList.iTotalRecords = this.queryable.Count();

            //  Filtered Data
            var records = this.queryable.Where(GenericSearchFilter());
            records = ApplySort(records);

            //  What is filtered data set count now.  This is NOT the
            //  count of what is returned to client
            formattedList.iTotalDisplayRecords = (records.FirstOrDefault() == null) ? 0 : records.Count();

            //  Take a page
            var pagedRecords = records.Skip(this.displayStart)
                     .Take(this.displayLength);

            //  Convert to List of List
            var aaData = new List>();
            var thisRec = new List();

            pagedRecords.ToList()
                    .ForEach(rec => aaData.Add(rec.PropertiesToList()));

            formattedList.aaData = aaData;

            return formattedList;
        }

That said, there is some trickery that goes on in order to make this happen because we are creating a solution to is going to work with any IQueryable to we supply. This means that the filtering and the sorting will need to be dynamic.

To make the filtering dynamic we will build expression trees that will convert each property to a string, convert the string to lower case, then execute a Contains method against the value of that property.  The method GenericSearchFilter() called on line 16 accomplishes this with the following lines of code:

//  Except from GenericSearchFilter
MethodInfo convertToString = typeof(Convert).GetMethod("ToString", Type.EmptyTypes);

 var propertyQuery = (from property in this.properties
        let toStringMethod = Expression.Call(                                          Expression.Call(Expression.Property(paramExpression, property), convertToString, null),                                                            typeof(string).GetMethod("ToLower", new Type[0]))
         select Expression.Call(toStringMethod, typeof(string).GetMethod("Contains"), searchExpression)).ToArray();

We get an array of Expressions that when executed will tell us if the value matches our search term. What we want is to include the item if ANY of the properties is a match, so this means we have to use and OR for all of the properties. That can be accomplished with:

for (int j = 0; j < propertyQuery.Length; j++)
{
  //  Nothing to "or" to yet
  if (j == 0)
  {
    compoundOrExpression = propertyQuery[0];
  }

  compoundOrExpression = Expression.Or(compoundOrExpression,
                                              propertyQuery[j]);
}

So with what is listed above we would be able to match all properties with against a single search term. Pretty cool. But DataTables raises the bar even higher. If you were to go to the samples page and filter using multiple partial words you would find that you could perform some very effective searches with phrases like “new chic”. This would select all records that had properties containing “new” OR “chic”. Imagine the scenario where your user wants to finds all cities “New York” or “Chicago”. We’ve all been there where we have a grid and can only search for one term, or worse, where we have to add a row to a search filter grid and constantly push a “query” button to perform our searches. DataTables does all of the with one search box – just type and the filtering begins.

GenericSearchFilter() handles that scenario. First the search term is parsed into individual terms if there is a ” ”  supplied in the string. This means we will have to perform the propertyQuery for each term that we have. To return all of the records that correspond to each term we still need to perform the OR in groups, but then we need to AND these predicates together so we can get all of the groups per individual term. Here’s the source edited slightly for readability:

//  Split search expression to handle multiple words
var searchTerms = this.genericSearch.Split(' ');

for (int i = 0; i < searchTerms.Length; i++) {    var searchExpression = Expression.Constant( searchTerms[i].ToLower());                   //  For each property, create a contains expression   //  column => column.ToLower().Contains(searchTerm)
  //  Edited for clarity - create the array propertyQuery logic is here ...
  var propertyQuery = ...

  //  Inner loop for grouping all OR's for this search term
  for (int j = 0; j < propertyQuery.Length; j++)   {     //  Nothing to "or" to yet     if (j == 0)     {       compoundOrExpression = propertyQuery[0];     }     compoundOrExpression = Expression.Or(compoundOrExpression, propertyQuery[j]);   }   //  First time around there is no And, only first set of or's   if (i == 0)   {     compoundAndExpression = compoundOrExpression;   }   else   {     compoundAndExpression = Expression.And(compoundAndExpression, compoundOrExpression);   } } 

So GenericSearchFilter will build a humongous expression tree for all the properties in your class. To make this usable for the Where we convert it using Expression.Lambda and our Where clause just goes about its merry way. Because we have used generics, you can supply any class from your assemblies. One caveat, and Sensei is trying to find a resolution. If you have a string property to that is set to null, the expression tree fails. You’ll note that in the classes supplied in the sample, the properties that are of type string in the Tenant class are defaulted to empty in the constructor.  A small price to pay for some great functionality. To sort our data we use the method ApplySort():

 private IQueryable ApplySort(IQueryable records)         {             string firstSortColumn = this.sortKeyPrefix.First();             int firstColumn = int.Parse(firstSortColumn);             string sortDirection = "asc";             sortDirection = this.aoDataList.Where(x => x.Name == INDIVIDUAL_SORT_DIRECTION_KEY_PREFIX +
                                                                      "0")
                                                .Single()
                                                .Value
                                                .ToLower();

            if (string.IsNullOrEmpty(sortDirection))
            {
                sortDirection = "asc";
            }

            return records.OrderBy(this.properties[firstColumn].Name, sortDirection, true);
        }

An extension method OrderBy will accept the name of column, the sort direction as parameters. The parameter initial will indicate if we are sorting mulitple times, so we can accomplish multi-property sort with syntax like

var sortedRecords = records.OrderBy("State", "desc", true)
                                      .OrderBy("City", "asc", false);

public static IOrderedQueryable OrderBy(this IQueryable source, string property, string sortDirection, bool initial)
        {
            string[] props = property.Split('.');
            Type type = typeof(T);
            ParameterExpression arg = Expression.Parameter(type, "x");
            Expression expr = arg;
            foreach (string prop in props)
            {
                // use reflection (not ComponentModel) to mirror LINQ
                PropertyInfo pi = type.GetProperty(prop);
                expr = Expression.Property(expr, pi);
                type = pi.PropertyType;
            }
            Type delegateType = typeof(Func<,>).MakeGenericType(typeof(T), type);
            LambdaExpression lambda = Expression.Lambda(delegateType, expr, arg);

            string methodName = string.Empty;

            //  Asc or Desc
            if (sortDirection.ToLower() == "asc")
            {
                //  First clause?
                if (initial && source is IOrderedQueryable)
                {
                    methodName = "OrderBy";
                }
                else
                {
                    methodName = "ThenBy";
                }
            }
            else
            {
                if (initial && source is IOrderedQueryable)
                {
                    methodName = "OrderByDescending";
                }
                else
                {
                    methodName = "ThenByDescending";
                }
            }

            object result = typeof(Queryable).GetMethods().Single(
                    method => method.Name == methodName
                            && method.IsGenericMethodDefinition
                            && method.GetGenericArguments().Length == 2
                            && method.GetParameters().Length == 2)
                    .MakeGenericMethod(typeof(T), type)
                    .Invoke(null, new object[] { source, lambda });
            return (IOrderedQueryable)result;
        }

All good things …
It’s been a long ride, this post. A lot of code discussed, a lot of ground covered. The solution is here.  As always, play around and see how this can help you. If anything breaks, tell Sensei. If you have improvements, tell Sensei. DataTables is a great tool for your arsenal, hopefully the DataTablePager can help you integrate paging with large datasets as part of your solution offering.

Right now Sensei wants to sign off by toasting to you for wading through all of this, and for having the desire to build up your skills.  Obtaining fluency in what you do is a hard road to travel, but it’s worth it because you get things done quicker and better with each session.

Be sure to read about the latest version in “Dynamically Select Columns with Server-Side Paging and Datatables.Net

Moncai – A Cloud Service for Mono and .Net December 2, 2010

Posted by ActiveEngine Sensei in .Net, ActiveEngine, Linux, Mono, New Techniques, Open Source.
Tags: , , , , , , ,
add a comment

If you have read these tomes of insanity posted by yours truly, you know that Sensei likes to stretch when it comes to finding solutions.  Aspiring to be an action hero in the everyday field of software development means you have to work like a dog, hunt like a tiger and crouch like a cricket.  This also means that you have to be flexible and willing to try new things.

Moncai, a service that will deploy your .Net / Mono app to the cloud via Git or Mercurial, looks very promising for those who want to try their hand at running their .Net application in the Linux realm.  As opposed to Azure, Moncai will offer POSIX distros for you to use.  The man behind the scenes, Dale Ragan, recently talked about Moncai in a HerdingCode podcast.  What he describes is a tiered approach to levels of service that you can have.  Dale wants to offer the hobbyist or midnight blogger a chance to experiment for free / low cost, and the services levels increase depending on your needs.  Dale even takes the time to communicate you via email when your first sign up, a real nice touch.  Go check it out and spread the word.

Prototyping With AnonymousTypes, CS-Script and JSON.Net – DataBuilder Part 3 November 14, 2010

Posted by ActiveEngine Sensei in .Net, ASP.Net, C#, CS-Script, DataBuilder, JSON.Net, New Techniques, Open Source.
Tags: , , , ,
4 comments

Sensei hit his head in the shower this morning and instead of the flux-capacitor he saw the following code that could be used for prototyping:

var jsonDataSet = AnonFactory.CreateList(10, new { FirstName = "",
                                 LastName = "",
                                 Age = 0,
                                 Salary = 45000})
                              .WhereAll()
                              .Have("FirstName", "Jim")
                              .BuildList()
                              .ToJSON();

If you have been following the series on DataBuilder, a utility that dynamically creates test data as JSON, you’ll recall one of the highlights was avoiding the need to create an additional Visual Studio project just so you could create test data.  DataBuilder can import your assemblies and with the use of NBuilder it creates test data for you.  You may wish to read those posts for some background.

But consider the scenarios where you do not have an application domain or a .Net assembly to test.  Should you stop?  For prototyping do you really need to compile, change, compile, change, show-to-your-user, repeat ad-nauseum?

Here’s a new concept:  Build data sets that you use in prototyping with Javascript before you break out Visual Studio.  If you can quickly build a tool set to communicate with your business users you’ll be much further ahead by avoiding the back-end client side impedance mismatch.  After all, many times the business user has the concept already hidden upstairs in their heads, why not help get that vision out in the open earlier and save yourself.

So, to be able to write the statement that Sensei saw in his vision we need to achieve to following goals:

  • Create an anonymous type as template for building a list
  • Create a fluent interface for chaining clauses similar to NBuilder
  • Serialize the list of anonymous types to JSON
  • Run this process in DataBuilder – in other words, go dynamic!

You may want to download the source and follow along.

AnonymousType as a Template

It turns out that Sensei has a tool in his bag of tricks, namely the Persistent Anonymous type.  As you are aware, anonymous types in C# have a limited scope, but the Persistent Anonymous type that Sensei discussed allows you to create a structure that mimics a standard anonymous type while being persist that structure beyond the scope of its creation.  The AnonymousType creator, Hugo Benocci created something really great.  Here’s what you can do from the get-go:

var anonType = AnonymousType(new {FirstName = "James",
                                         Middle = "T",
                                         LastName="Kirk"
                                   });

If you recall the examples used in the prior posts on data generation with DataBuilder, NBuilder supplied default values for you when you built an object. You then had to alter those values should you want something different.

With an AnonymousType we use a factory to create a list of AnonymousTypes like so:

var anonTypeList = AnonFactory.CreateListSizeOf(10,
                                  new {FirstName = "James",
                                         Middle = "T",
                                         LastName="Kirk"
                                   });

Nice and simple. If we didn’t have more goals to achieve, we could go home. As it is, on to the next step.

Creating a Fluent Interface for Chaining Clauses

We still need to provide variation in our data set.  NBuilder does a nice job of letting us use clauses like .WhereTheNext(5).Have() or WhereAll.Have() to introduce more structured variation in our data.  We want to achieve the same thing with the AnonymousTypes and can do the following:

var anonTypeList = AnonFactory.CreateListSizeOf(10,
                                  new {FirstName ="",
                                         Middle = "",
                                         LastName=""
                                   })
                                   .WhereAll()
                                       .Have("FirstName", "William")
                                       .Have("LastName", "Riker")
                                   .BuildList();

Like NBuilder we want to specify that different segments get different values. Here’s how that is accomplished:

var anonTypeList = AnonFactory.CreateListSizeOf(10,
                                  new {FirstName = "",
                                         Middle = "",
                                         LastName=""
                                   })
                                   .WhereTheFirst(5)
                                       .Have("FirstName", "William")
                                       .Have("LastName", "Riker")
                                   .AndTheNext(5)
                                       .Have("FirstName", "Jean-Luc")
                                       .Have("LastName","Picard")
                                   .BuildList();

There is also a WhereTheLast() clause for working with data at the end of a list.  All of these extension methods are contained in Extensions.cs.

Now let’s talk about how this works. For our purposes a fluent interface allows us to chain methods together yielding a more readable syntax. This is achieved with methods that return a reference to it’s class as in:

class RetangleCreator
{
    private decimal width;
    private decimal height;
    private string color;

    public RectangleCreator SetWidth(decimal width)
    {
        this.width = width;
        return this;
    }

    public RectangleCreator SetHeight(decimal height)
    {
        this.height = height ;
        return this;
    }

    public RectangleCreator SetColor(string color)
    {
        this.color= color;
        return this;
    }
}

var rectangleCreator = new RectangleCreator()
                                         .SetHeight(4.5)
                                         .SetWidth(5.75)
                                         .SetColor("red");

With a collection or list you might be tempted to create code that simply passes on the list after performing some action. This is fine until you need to perform actions on specific segments of that list. In our case we need to know where an action has left of in order to achieve syntax like WhereTheNext(5).Have(…).AndTheNext(5).

The class AnonTypeRange accomplishes this and allows us to perform actions on a list of AnonymousTypes in the manner we desire. Here is the code:

public void SetRange(int start, int amount)
{
    Enforce.ArgumentGreaterThanZero(amount, "AnonTypeRange.Next - amount must be greater than start");
    Enforce.That((start >= 0), "AnonTypeRange.Next - start must be greater than or equal to 0");
    Enforce.That((amount + start <= this.limit), "AnonTypeRange.Next - amount can not be greater than limit");     this.Start = start;     this.End = (start + amount - 1) > limit ? limit : start + amount - 1;
        }

The ranges themselves are set in the extension methods that comprise our syntax. Examine WhereTheNext() and AndTheNext() methods:

public static AnonTypeRange WhereTheFirst(this List anonTypes, int amount)
{
    Enforce.ArgumentGreaterThanZero(amount, "AnonTypeRange.WhereTheFirst - amount can not be less that 0");

    var anonTypeRange = new AnonTypeRange(anonTypes);
    anonTypeRange.SetRange(0, amount);

    return anonTypeRange;
}

public static AnonTypeRange AndTheNext(this AnonTypeRange anonTypeRange, int amount)
{
    Enforce.ArgumentGreaterThanZero(amount, "AnonTypeRange.AndTheNext - amount can not be less that 0");

    anonTypeRange.SetRange(anonTypeRange.End + 1, amount);

    return anonTypeRange;
}

The only drawback is that the actions are processed serially. In other words you do a group of 5, then another group of 5. If you need to go back you could add a WhereTheFirst() to reset the position of operations.

Before we move on take note of the WhereAll() method. This takes in a List and returns a AnonTypeRange with the range set to 0 spanning to the end:

public static AnonTypeRange WhereAll(this ListanonTypes)
{
    var anonTypeRange = new AnonTypeRange(anonTypes);
    anonTypeRange.SetRange(0, anonTypes.Count);

    return anonTypeRange;
}

Our values are set with the Have clause. Again we try to mimic the great functionality of NBuilder, so you have two options.  You can set a single value on a property over a range:

//  Have
public static AnonTypeRange Have(this AnonTypeRange anonTypeRange, string property, object value)
{
    anonTypeRange.Apply(property, value);
    return anonTypeRange;
}

//  Have calls AnonTypeRange.Apply to save the properties
public void Apply(string property, object value)
{
    Enforce.ArgumentNotNull(property, "AnonTypeRange.Apply - property can not be null");
    Enforce.ArgumentNotNull<object>(value, "AnonTypeRange.Apply - value can not be null");

    int count = (this.End - Start) + 1;
    var range = this.internalAnonList.GetRange(this.Start, count);
    range.ForEach(x => x.Set(property, value));                    }

Or you can create a list of values that will be selected at random and distributed across the range.  This takes advantage of the Pick functionality provided by NBuilder and is quite useful.

public void Apply(string property, List<T>pickList)
{
    Enforce.ArgumentNotNull(property, "AnonTypeRange.Apply - property can not be null");

    int count = (this.End - Start) + 1;
    var range = this.internalAnonList.GetRange(this.Start, count);

    range.ForEach(x => x.Set(property, Pick.RandomItemFrom(pickList)));
}

Serializing the List of AnonymousTypes

AnonymousType has a method that will serialize the properties that it contains.  Since AnonymousType stores the properties and respective values in a Dictionary it’s fairly easy to searlize the Dictionary.  The method uses the JObject from JSON.Net, but you can come up with your own mechanisms if you like:

//  From AnonymousType
public string ToJSON(Func , string, string> function,
                                                string jsonObjectName)
    {
        return function(_Values, jsonObjectName);
    }
//  Delegate method for serializing
public static string SerializeWithJObject(Dictionary values, string name)
{
    var jsonObject = new JObject();

    foreach (KeyValuePair property in values)
    {
        jsonObject.Add(new JProperty(property.Key, property.Value));
    }

    return jsonObject.ToString();
}

Serializing a list of AnonymousTypes is as equally straight forward to accomplish.  You only need to traverse the list and call the ToJSON methods on each AnonymousType object.  So easy it almost makes you feel guilty!

Dynamically Generate Data Sets with DataBuilder

If you’ve made it this far, congratulations, it’s been a bit of a marathon.   What is striking is how very straight forward much of this has been.  And the icing on the cake is that you can use the Snippet section of DataBuilder to run the code.  This required a slight alteration to the ScriptHostBase file, as it was expecting a path to an assembly.  Since the goal is to generate data sets without assemblies it would be pretty silly if you had supply something in the Assembly Path section.  All you need to do is supply something like the code below in the Code Snippet and hit “Build Data”:

var namesPickList = new List();
namesPickList.Add("Geordi");
namesPickList.Add("Que");
namesPickList.Add("Data");
namesPickList.Add("Jean-Luc");

string json = AnonFactory.CreateListOfSize(10,
                     new { LastName = "Kirk",
                              FirstName = "James",
                              MiddleInitial = "T." })
                      .WhereAll()
                            .Have("FirstName", namesPickList)
                      .BuildList()
                      .ToJSON();

parameters["JsonDataSet"] = json;

Faster than a photon torpedo you get back JSON. Now you’re set to start your HTML / Javascript prototypes. Need to alter the data, update the snippet and run it again.  Here’s the new source code, and prototype away!

How Embedded Scripting Makes Dynamically Generated Test Data Possible in ASP.Net – DataBuilder Part 2 November 6, 2010

Posted by ActiveEngine Sensei in .Net Development, ActiveEngine, ASP.Net, C#, CS-Script, DataBuilder, JSON.Net, NBuilder, Problem Solving.
Tags: , , , , , ,
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Part 1 of a 3 part series.  For the latest DataBuilder capabilities, read this post or download the new source code from here.

Last episode Sensei unveiled a useful little tool called DataBuilder.  DataBuilder helps you to generate test data for you domain objects.  Just point DataBuilder to your assemblies, and with the magic of NBuilder, CS-Script you can create test data as JSON.  How is this possible?  This post will focus on the behind the scenes magic that makes DataBuilder so flexible.

The main problem that DataBuilder solves is that to create test data for your classes you normally need to fire up Visual Studio and a project, create code, compile, etc. to produce anything and this can cause needless context switching and headache.  What if you wish to simply wish to mock up a UI and need some data sets to work with?  DataBuilder helps in that you can create test data for any existing assembly.  You can also create different types of test data based on what ever criteria you need.  This is accomplished by taking the input supplied in the Snippet Editor screen, compiling it to an in-memory assembly and executing it.  No need to fire up Visual Studio and add a TestGeneration project to your .Net solution.

The “dynamic” nature of DataBuilder is implemented with CS-Script.  In short, CS-Script is an embedded scripting system that uses ECMA-compliant C #, with full access to the CLR and OS.  For an in-depth review see  Oleg Shilo’s fantastic article on CodeProject where he describes his product.

As Oleg describes, CS-Script will compile your code into an assembly, load that assembly into a separate app domain, then execute that assembly.  There are two scenarios that can be used to host your script.  They are the Isolated Execution Pattern, where the host and script have no knowledge of each other, and the  Simplified Hosting Model for two way type sharing between the host and the script.  The Simplified Hosting Model allows the script file to access assemblies loaded in the host, as well as pass back data to the host.  DataBuilder uses the Simplified Host Model.

Before we get into the particular DataBuilder code, let’s review some samples that Oleg has provided.  The scenario presented is when you wish to remotely load a script and execute it, and the recommendation is to user interface inheritance to avoid the task of using reflection to invoke the method.

// Host contains this interface:
public interface IWordProcessor
{
void CreateDocument();
void CloseDocument();
void OpenDocument(string file);
void SaveDocument(string file);
}

//  The script file implements the interface
public class WordProcessor: IWordProcessor
{
public void CreateDocument() { ... }
public void CloseDocument() { ... }
public void OpenDocument(string file) { ... }
public void SaveDocument(string file) { ... }
}

//  Host executes the script
AsmHelper helper = new AsmHelper(CSScript.Load("script.cs", null, true));

//the only reflection based call
IWordProcessor proc = (IWordProcessor)helper.CreateObject("WordProcessor");

//no reflection, just direct calls
proc.CreateDocument();
proc.SaveDocument("MyDocument.cs");

There are other methods for invoking methods and scripts. It’s well worth your time reading through the script hosting guidelines as Oleg covers performance, reflection, interface alignment with duck typing and other facets that are important to CS-Script.

Now let’s focus on DataBuilder’s embedded scripting implementation.  DataBuilder uses the interface inheritance approach to execute the script that you supply.  Here’s the interface:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace DataGenerator.ScriptHost
{
    public interface IScriptRunner
    {
        void RunScript();
        void RunScript(Dictionary<string, object> parameters);
    }
}

And here is an implementation of the interface:

//CSScript directives - DO NOT REMOVE THE css_ref SECTION!!!
//css_ref System.Core;
//css_ref System.Data.ComponentModel;
//css_ref System.Data.DataSetExtensions;
//css_ref System.Xml.Linq;

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using DataGenerator.Core;
using DataGenerator.ScriptHost;
using System.Linq.Expressions;
using System.Linq;
using Newtonsoft.Json;
using FizzWare.NBuilder;
//  Add a reference to your assemblies as well!!
using UnRelatedAssembly;

public class CreateTestFile : IScriptRunner
{
    public void  RunScript(Dictionary<string,object> parameters)
    {
        var agents = Builder<SalesAgent>.CreateListOfSize(5)
                    .WhereTheFirst(1)
                         .Have(x => x.FirstName = "James")
                         .And(x => x.LastName = "Kirk")
                    .AndTheNext(1)
                          .Have(x => x.FirstName = "Bruce")
                          .And(x => x.LastName = "Campbell")
                    .Build()
                    .ToList();

        parameters["JsonDataSet"] = JsonConvert.SerializeObject(agents);
    }

    public void  RunScript()
    {
 	    throw new NotImplementedException();
    }
}

The script host is derived from ScriptHostBase.  ScriptHostBase will perform the compilation of your script with the method CompileScript(), as well as fetching any remote assemblies that you want to include.  This is a great point of flexibility as it allows you to point to any assembly that you have access to.  Assemblies can come from multiple locations, and as long as you know the namespaces you can include the classes from those assemblies in your scripts.

        /// <summary>
        /// Compile a script and store in a runner object for later
        /// execution
        /// </summary>
        protected void CompileScript()
        {
            if(string.IsNullOrEmpty(this.Script))
            {
                throw new ArgumentNullException("ScriptHostBase - CompileScript : Script can not be blank");
            }

            if (string.IsNullOrEmpty(this.TypeName))
            {
                throw new ArgumentNullException("ScriptHostBase - CompileScript : TypeName can not be blank");
            }

            //  Has an assembly already been loaded?
            string names = string.Empty;
            AppDomain appDomain = AppDomain.CurrentDomain;

            var assemblyPaths = appDomain.GetAssemblies()
                                    .ToList()
                                    .Select(x => x.FullName)
                                    .ToList();

            var fizzWare = assemblyPaths.Where(x => x.Contains("FizzWare.NBuilder"))
                                            .SingleOrDefault();

            var assemblyLoadList = new List<string>();
            assemblyLoadList = this.AssemblyPaths.ToList();

            //  Load if needed
            if (fizzWare != null)
            {
                string remove = assemblyLoadList
                                     .Where(x => x.Contains("FizzWare.NBuilder"))
                                     .SingleOrDefault();
                assemblyLoadList.Remove(remove);
            }
            else
            {
                string path = ConfigurationManager.AppSettings["FizzWarePath"].ToString();
                assemblyPaths.Add(path);
            }

            Assembly compiler = CSScript.LoadCode(this.Script, assemblyLoadList.ToArray());
            AsmHelper asmHelper = new AsmHelper(compiler);
            this.runner = asmHelper.CreateObject(this.TypeName);
        }

You may be scratching your head at the lines of code that explicitly load FizzWare.NBuilder(26 -43).  When first constructing DataBuilder, Sensei struggled with getting NBuilder to compile with the new script.  CS-Script uses an algorithm to probe directories for assemblies as well as probing scripts to resolve namespaces.  In some cases, this probe will NOT locate a namespace based on the naming conventions of an assembly. CS-Script has provisions for handling those scenarios allowing you to specifically load an assembly.  The issue Sensei had at first was that the first execution of a script would complete successfully as NBuilder would be loaded.  The problem lay with the second run of the script, as an exception would be thrown claiming that NBuilder was already loaded and hence there was no need to explicitly load it again!  The work around is to query the loaded assemblies and if NBuilder is loaded, remove that path to FizzWare.NBuilder assembly from the AssemblyPaths list and prevent the script from reloading NBuilder.

Classes derived from ScriptHostBase are responsible for implementing ExecuteScript method.  In this implementation StringScriptHost derives from ScriptHostBase and has the following ExecuteScript method:

        /// <summary>
        /// Compile a script and invoke
        /// </summary>
        public override void ExecuteScript()
        {
            base.CompileScript();

            IScriptRunner scriptRunner = (IScriptRunner)this.runner;
            scriptRunner.RunScript(Parameters);
        }

Other script hosts can be created and handle scenarios where scripts stored in a document database, text fields in SQL Server or other scenarios.

The process of including your import statements, locating any scripts located on a share and passing parameters to scripts is all controlled by the ScriptController.  There are two constructors with one allowing you to specify the script location:

public ScriptController(string scriptShare){}

With the ScriptController you can execute snippets that you type free form with the method ExecuteSnippet.

public void ExecuteSnippet(string snippet, Dictionary<string, object> parameters)
        {
            Enforce.ArgumentNotNull<string>(snippet, "ScriptController.ExecuteAdHoc - snippet can not be null");

            //  Wrap snippet with class declaration and additional using ;
            snippet = snippetHeader + this.UsingFragment + snippetClassName +
                        snippet + snippetFooter;

            var scriptHost = new StringScriptHost();
            scriptHost.Script = snippet;
            scriptHost.TypeName = "AdHoc";
            scriptHost.Parameters = parameters;
            scriptHost.AssemblyPaths = this.assemblyPaths.ToArray();

            scriptHost.ExecuteScript();
        }

Another method ExecuteScript is used for executing script files that you have save on a share.  As you read through the ExecuteSnippet method, you’ll note that the controller will combine the required import and namespace methods.  It’s really just concatenating strings to build a complete script in the format displayed above in the CreateTestFile.cs code.

You create a Dictionary<string, object> called parameters and pass this to the ScriptController.Execute methods.  This allows you great flexibility as you can allow the scripts to instantiate different objects and return them to the host application for further use.  In the case of DataBuilder we are expecting a JsonDataSet object which is our serialized test data in the form of JSON.

That’s it.  Hopefully you find DataBuilder and these posts useful.  CS-Script is quite powerful and can allow you to execute operations without the need to constantly recompile your projects.  It also allows to execute operations dynamically.  DataBuilder would not be possible without it.  When duty calls and fluent solutions are needed, CS-Script and embedded scripting are pretty incredible. Source code is here.

Dynamically Create Test Data with NBuilder, JSON and .Net October 24, 2010

Posted by ActiveEngine Sensei in .Net, ActiveEngine, Ajax, ASP.Net, C#, Fluent, LINQ, Open Source, Problem Solving.
Tags: , , , , ,
5 comments

Part 1 of a 3 part series.  For the latest DataBuilder capabilities, read this post or download the new source code from here.

Building test data should be as easy:

var agentList = Builder<SalesAgent>.CreateListOfSize(5)
                           .WhereTheFirst(1)
                                  .Have(x => x.FirstName = "James")
                                  .And(x => x.LastName = "Kirk")
                            .AndTheNext(1)
                                  .Have(x => x.FirstName = "Bruce")
                                  .And(x => x.LastName = "Campbell")
                            .Build()
                            .ToList();

Wouldn’t be nice if all the properties of your objects were automatically populated:

Product:
       Id              : 1
       Title           : "Title1"
       Description     : "Description1"
       QuantityInStock : 1

NBuilder by provides you with a great fluent interface to accomplish this with ease.  You can even achieve scenarios where you can create hierarchies of data, set property values on a range objects in a list, and even create a specified range of values that you can use populate other objects.  Peruse through the samples and you will see, NBuilder quite capably maps values  the public properties of your objects.  A real time saver.

Sensei is going to kick it up a notch and provide you with a means to create test data with out having to recompile your projects.  This is ideal for when you want to create UI prototypes.  DataBulider uses CS-Script and NBuilder to create a web based data generation tool that can read assemblies and will allow you to script a process that will generate test data in the form of JSON.

This adventure is split into two parts.  First a quick demo, then instructions on how to configure DataBuilder for you environment.  A deeper discussion of CS-Script and embedded scripting in .Net will be part of the sequel to this action/adventure, as we all know the second movie in the series is always the best!.

Operating DataBuilder

In short you have three things to do:

  • Identify the assemblies that contains the objects you want to generate test data for.  The path to the files can be anywhere on your system.  For convenience there is an folder called Assembly that you can copy the files to.  Multiple assemblies from different locations can be imported.
  • Create the import statements.
  • Create the code snippet with the NBuilder statements that will generate your data.

Here’s a screen shot of DataBuilder with each section that corresponds with the three goals stated above.

And here is an example that we’ll be working with.

var agents = Builder<SalesAgent>.CreateListOfSize(5)
                    .WhereTheFirst(1)
                         .Have(x => x.FirstName = "James")
                         .And(x => x.LastName ="Kirk")
                    .AndTheNext(1)
                          .Have(x => x.FirstName = "Bruce")
                          .And(x => x.LastName = "Campbell"})
                    .Build()
                    .ToList();

parameters["JsonDataSet"] = JsonConvert.SerializeObject(agents);

Note that after the end of the code that creates the objects, you need to include a statement

parameters["JsonDataSet"] = JsonConvert.SerializeObject(List);

Without that statement you will not get your data serialized.  If you’ve entered the data as shown, hit the Build button and the resulting JSON is placed in the output box.  That’s it.  Looking through the output you’ll note that the first two sales dudes are James Kirk and Bruce Campbell, while the remaining records are completed by NBuilder.

[{"FirstName":"James","LastName":"Kirk","Salary":1.0,"RegionId":1,"RegionName":"RegionName1","StartDate":"\/Date(1287892800000-0400)\/"},{"FirstName":"Bruce","LastName":"Campbell","Salary":2.0,"RegionId":2,"RegionName":"RegionName2","StartDate":"\/Date(1287979200000-0400)\/"},{"FirstName":"FirstName3","LastName":"LastName3","Salary":3.0,"RegionId":3,"RegionName":"RegionName3","StartDate":"\/Date(1288065600000-0400)\/"},{"FirstName":"FirstName4","LastName":"LastName4","Salary":4.0,"RegionId":4,"RegionName":"RegionName4","StartDate":"\/Date(1288152000000-0400)\/"},{"FirstName":"FirstName5","LastName":"LastName5","Salary":5.0,"RegionId":5,"RegionName":"RegionName5","StartDate":"\/Date(1288238400000-0400)\/"}]

You also can load a script and execute it as well.  That’s done on the “Script Loader” tab.  The location of the scripts is set in the WebConfig and the key name is ScriptPath.  Here’s the screen shot:

Anatonomy of DataBuilder Script

Here’s the complete C# script file that builds your data.  It’s just a class:

//CSScript directives - DO NOT REMOVE THE css_ref SECTION!!!
//css_ref System.Core;
//css_ref System.Data.ComponentModel;
//css_ref System.Data.DataSetExtensions;
//css_ref System.Xml.Linq;

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using DataGenerator.Core;
using DataGenerator.ObjectTypes;
using DataGenerator.ScriptHost;
using System.Linq.Expressions;
using System.Linq;
using Newtonsoft.Json;
using FizzWare.NBuilder;
//  Add a reference to your assemblies as well!!
using UserDeploymentDomain;

public class CreateTestFile : IScriptRunner
{
    public void  RunScript(Dictionary parameters)
    {
        var agents = Builder.CreateListOfSize(5)
                    .WhereTheFirst(1)
                         .Have(x => x.FirstName = "James")
                         .And(x => x.LastName = "Kirk")
                    .AndTheNext(1)
                          .Have(x => x.FirstName = "Bruce")
                          .And(x => x.LastName = "Campbell")
                    .Build()
                    .ToList();

        parameters["JsonDataSet"] = JsonConvert.SerializeObject(agents);
    }

    public void  RunScript()
    {
 	    throw new NotImplementedException();
    }
}

The very top section “CSScript Directives” is required by CS-Script.  These are directives that instruct the CS-Script engine to include assemblies when it compiles the script.  The imports section is pretty straight forward.

You’ll note that the script inherits from an interface.  This is a convention used by CS-Script to allow the host and script to share their respective assemblies.  Sensei will discuss that in next post.  The RunScript method accepts a Dictionary that contains the parameters.  This will house the JsonDataSet that is expected for the screen to display the output of your data.

Advanced NBuilder Experiments
The beauty of NBuilder is that you can create test data that goes beyond “FirstName1”, and allows you to quickly create data that matches what the business users are used to seeing. If you think about it you should be able to generate test data that will exercise any rules that you have in the business domain, such as “Add 5% tax when shipping to New York”. With the scripting capability of DataBuilder you can create suites test data that can evolve as you test your system. You could also use the JsonDataSet to create mocks of your objects as well, maybe use them for prototyping your front end.

We’ll do a quick sample. Our scenario is to create assign real regions to sales agents. Furthermore, we want to only chose a range of regions and assign them at random.

First we build the Regions:

var regions= Builder<Region>.CreateListOfSize(4)
	.WhereTheFirst(1)
		.Have(x => x.State = "Texas")
	.AndTheNext(1)
		.Have(x => x.State = "California")
	.AndTheNext(1)
		.Have(x => x.State = "Ohio")
	.AndTheNext(1)
		.Have(x => x.State = "New York")
	.Build();

Now we’ll create a SalesAgents and using the Pick method from NBuilder we’ll randomly assign a region to the sales agents:

var agents = Builder<SalesAgent>.CreateListOfSize(5)
                    .WhereAll()
                           .HaveDoneToThem(x => x.RegionName = Pick.RandomItemFrom(regions).State)
                    .WhereTheFirst(1)
                         .Have(x => x.FirstName = "James")
                         .And(x => x.LastName = "Kirk")
                    .AndTheNext(1)
                          .Have(x => x.FirstName = "Bruce")
                          .And(x => x.LastName = "Campbell")
                    .Build()
                    .ToList();

The result set now has the range of states distributed to the Sales Agents. Looks like James Kirk needs to cover Texas. You may need to view the source to see the output.

[{"FirstName":"James","LastName":"Kirk","Salary":1.0,"RegionId":1,"RegionName":"Texas","StartDate":"\/Date(1287892800000-0400)\/"},{"FirstName":"Bruce","LastName":"Campbell","Salary":2.0,"RegionId":2,"RegionName":"Texas","StartDate":"\/Date(1287979200000-0400)\/"},{"FirstName":"FirstName3","LastName":"LastName3","Salary":3.0,"RegionId":3,"RegionName":"California","StartDate":"\/Date(1288065600000-0400)\/"},{"FirstName":"FirstName4","LastName":"LastName4","Salary":4.0,"RegionId":4,"RegionName":"California","StartDate":"\/Date(1288152000000-0400)\/"},{"FirstName":"FirstName5","LastName":"LastName5","Salary":5.0,"RegionId":5,"RegionName":"Ohio","StartDate":"\/Date(1288238400000-0400)\/"}]

Configure DataBuilder For Your Environment
Given that DataBuilder is loading assemblies you will want to run it on either your dev environment or on a test server where your co workers won’t mind if you need to take IIS up and down. Also, you’ll want to work with a copy of your assemblies in case you need to make a quick change. There are times when IIS will not release a file and if you need to make changes to the assemblies themselves it’s more convenient to copy them after you’ve re-compiled.

There are two settings you need to change in the WebConfig to match your environment.

ScriptPath – Point this to the share where you want to save any scripts. DataBuilder will scour the directory and list anything you place in there.

FizzWarePath – This needs to point to the location of the NBuilder dll. Most likely this will be the bin folder of the DataBuilder website. In the follow up post Sensei will explain what this does.

Wrapping Up For Now

We covered a lot on the whirlwind tour of DataBuilder.  There’s a lot more that is of interest, particularly with respects to the embedded scripting aspects provided by CS-Script.  For now, have fun playing building you data sets.  In the next installment we’ll cover the scripting aspect in more detail  For now, download and experiment.  Here’s the source for DataBuilder with unit tests.

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