Windows 7 makes searching for content much easier with Federated Search. In this post I’ll talk about how to how to create a Flickr Federated Search Providers in .Net.

Before We Start

This sample uses Flickr API through Flickr.Net. In order to build your own version of this Flickr Federated Search Connector:

• Download Flickr.Net from CodePlex
• Acquire your API and Secret Keys for Flickr API.

Create a new ASP.Net Web Application

Create a new ASP.Net Web Application with Visual Studio.

Add the Flickr.Net project (called FlickrNet.csproj) to your solution, and add a reference to it from your web application.

Add the Flickr API and Secret Key’s to your web.config in the AppSettings section:

Create the Flickr Search Provider

The following provider will be executed by the Windows Explorer client using HTTP GET, and will receive several parameters from it:

http://localhost:52903/Search.aspx?q=TechEdIsrael2008&start=1&count=20

It will perform the search against Flickr, and return the response as RSS.

Create a new Web Form called Search.aspx.

To make it easier to test the response, right click the web application, and open the Properties window. Go to the Web pane, select Search.aspx as the start page and provide the query parameters:

In the page markup, add a new asp:Repeater control that will define the template for each item in the response:

In the page code behind, implement the logic that uses Flickr.Net to search for photos and bind the result to the repeater control:

In the code above I first grab the API and secret key’s from the configuration file and then, I extract the parameters from the query string. I create a new instance of the Flickr object, and perform the actual search for photos, providing the page number and the number of items in each page. Finally, I bind the returned photo collection the the repeater control.

Replace the html header and footer with RSS header and footer in Search.aspx.

Before:

After:

Set the ItemTemplate of the Repeater control to display the photos data according to the output format:

Run the application. The browser should navigate to Search.aspx passing all the relevant query parameters. The response should be an RSS feed that contains items per photos found.

Creating the Flickr Federated Search Connector

Add a new Xml file to the project and name it FlickrFederatedSearch.osdx (stands for OpenSearch Description Xml). This file contains the data that Windows Explorer needs to order to perform the search against the search service.

Notice in the above xml that the parameters are taken from some predefined names ({searchTerms}, {count} etc.), and the ampersands (&) are Html encoded.

Right click the .osdx file, and select Open With.

 
In the Open With dialog, select Windows Explorer.

In the Add Search Connector dialog, click Add.

Now, Flickr Federated Search appears in the Favorites section in Windows 7 Explorer and you can use it for searching items.

Summary

In this post I’ve talked about how to create a Flickr Federated Search Connector for Windows 7 in .Net. The above provider provides basic features and can be enhanced with more capabilities described in the Windows 7 Federated Search Provider Implementer’s Guide.

Enjoy!

In this post I’ll talk about adding jQuery IntellSense in Visual Studio 2008, and how to add jQuery to a simple Web Application inside Visual Studio 2008.

jQuery IntelliSense in Visual Studio 2008 - KB946581

In order to use jQuery in Visual Studio 2008 with IntelliSence a hotfix for Visual Studio 2008 must be installed:

1. Download the hotfix from Connect
2. Run the executable and extract its contents to a folder in your hard drive.
3. Make sure all instances of Visual Studio 2008 are closed, and run VS90-KB946581.exe from the above folder.

Download the Latest jQuery Library + Documentation

To use jQuery in Visual Studio 2008, and enjoy its IntelliSense, you should download 2 javascript files. One contains the actual jQuery library, and the second contains the library with documentation for Visual Studio 2008 to display its IntelliSense.

1. Go to jQuery Official Download Page
2. Scroll down and find the Current Release section.
3. Download the Uncompressed version (jquery-1.2.6.js) and the documentation for Visual Studio (jquery-1.2.6-vsdoc.js).

Using jQuery in a Visual Studio 2008 Web Application

In a new Web Application or inside an existing one, add the jQuery scripts into a certain folder.

In a web page (or a master page), add a reference to the jQuery library:

Then, in any javascript function you can start using jQuery functions and enjoy the IntelliSense in Visual Studio 2008.

A Simple Example of Using jQuery Functions

For example, Assuming that you have a page with the following content in it:

This form contains a single textbox followed by a button.

The handleButtonClick() function handles the button onclick event.

The way jQuery works is by selecting DOM elements and then doing something with them, such as executing a function or applying some properties. For example:

The above method uses the selector function $ to select DOM elements (in this case – a single element with id = txtName) and to apply a style property of a red border. Running this page and clicking the button results in this output:

Summary

In this post I talked about the steps you should follow in order to use jQuery in Visual Studio 2008 with InstelliSense support. Then, we used jQuery in a simple web application.

From Twitter API Documentation page:

User Timeline:

Returns the 20 most recent statuses posted from the authenticating user:

https://twitter.com/statuses/user_timeline.xml

It's also possible to request another user's timeline. For example:

https://twitter.com/statuses/user_timeline/bursteg.xml

Making an HTTP Request

Since all the API is expressed in REST, I figured out that I need a simple reusable method to perform HTTP requests. This method takes the URL and the method (GET or POST), gets the credentials from the configuration file and makes the request.

Just for the simplicity, I also added the following methods:

Getting a User’s Time Line from Twitter

Using the following code, you can get a user’s timeline from twitter in xml  format:

This call returns the following piece of xml:

As we can see, this response is an array of statuses, each contains the details about the user who posted it.

Extracting the Data

With my favor to LINQ to XML, I used it to extract the data that I was interested in, and construct CLR objects that I can easily work with.

First, I parsed an xml document from the response string. Then, I created a list of UserStatus objects from the contents of the response xml.

Few things to note about the above code:

1. HttpUtility.HtmlDecode is being used in order to get a readable text. The response contained text like “Testing "posts" #devacademy3” and this method (in System.Web) converts it to “Testing “posts” #devacademy3”.

2. The ParseDateTime() method on the element’s value is an extension method I created in order to parse a DateTime from the special string representation of the time the status was posted:

Sat Nov 15 10:08:15 +0000 2008

This method looks like:

If you come up with another idea of how to parse this string into a DateTime object, please let me know.

Wrapping it up...

The final version of the GetUserTimeLine method looks like this:

The techniques I’ve used here can be used in almost all the “get” methods of the REST API of Twitter.

Enjoy!

When you install Windows Azure Tools for Visual Studio, you only get a project template for an ASP.Net Web Role. In this post I’ll talk about how to create a new ASP.Net MVC Web Role or move an existing ASP.Net MVC Application to Windows Azure.

There are 2 ways to do this:

• Manually adding an ASP.Net MVC application as a Web Role (suitable both for a new ASP.Net MVC application and for an existing one).
• Use a Project Template to simply create a new ASP.Net MVC Web Role (new ASP.Net MVC application only).

Creating a New ASP.Net MVC Web Role

The following steps apply both for creating a new ASP.Net MVC application and to moving an existing ASP.Net MVC application to Windows Azure.

1. Create an empty ASP.Net MVC Application (with or without a test project), or make sure you have an existing ASP.Net MVC application that you want to move to the Windows Azure.

2. Close this solution and create a new Blank Cloud Service. Make sure you start Visual Studio as an administrator because working with the Development Fabric requires that.

3. Add an existing project to the cloud service and select the ASP.Net MVC Application you have created earlier.

4. Right click the ASP.Net MVC project and select Unload Project.

5. When the project is unloaded, right click it and edit the project file.

6. The project file opens in the XML Editor.

Inside the PropertyGroup Element, add the RoleType element and mark this ASP.Net MVC project as a Web Role.

7. Close this project file, and reload the project.

8. Since the ASP.Net MVC now runs on the Windows Azure Service Hosting environment and will probably use its services – add a reference to Microsoft.ServiceHosting.ServiceRuntime.dll.

9. Right click the Roles node in the project tree, and add a Web Role Project in the solution. Select the ASP.Net MVC project from the project list.

Now the ASP.Net MVC project is shown as a Web Role.

10. Since the Windows Azure provides us only with the default .Net Framework 3.5 SP1 assemblies, we must make sure we also copy the ASP.Net MVC Assemblies to the cloud. To do this, right click on each of the following references of the ASP.Net MVC application, and set the Copy Local property to True:

• System.Web.Abstractions
• System.Web.Mvc
• System.Web.Routing

That’s it. You can run the application to make sure that it is running on the Development Fabric.

Creating an ASP.Net MVC Web Role using a Project Template

Thanks to a great word done by the community, we can use a project template to do all the above steps for us. Here’s how to do this:

1. Download the project template from Codeplex at http://c4mvc.codeplex.com/.

2. Create a new project and select the Azure ASP.Net MVC template in the Community for MVC category.

This creates a new Cloud Service for Windows Azure with ASP.Net MVC Application as a Web Role.

Enjoy!

The Microsoft WF/WCF using Visual Studio 2010 and .NET Framework 4 Training Kit includes presentations, hands-on labs, and demos. This content is designed to help you learn how to utilize the Visual Studio 2010 features and a variety of WF and WCF new features.

• Learn basic workflow creation, hosting and running , and test-drive workflow development.
• Get an introduction to workflow services, communication between workflows and content based correlation of workflow instances.
• Use the flexibility of Flowchart workflow activities to implement non-sequential workflows.
• Learn how to rehost the workflow designer in a WPF desktop application and customize it in several ways.
• Learn how you can leverage some of the main WF and WCF monitoring features to track application execution and troubleshoot problems with services when necessary.
• Learn how Service discovery allows you to locate services on the same subnet using ad hoc discovery, or using a proxy to establish connections with servers regardless of where they are.

This version of the training kit is compatible with Visual Studio 2010 Beta 1.

Download here.

This is another post in my WF 4.0: Custom Activities series. In a previous post I have talked about creating a code only custom activity that performs a simple task. In this post I’ll talk about creating a more complex activities that takes inputs from the calling program during their execution.

In the previous post WF 4.0: Code Only Custom Activities for Atomic Actions | CodeActivity, CodeActivity<T> I implemented the following activity for reading a string from the console.

While this activity will perform the task it is meant to do, it is blocking the calling thread and bad for scalability. In addition to that It is bound to getting the value from the console only, and it is not generic enough to support another input methods.

Enter Bookmarks.

Using NativeActivity for Complex Activities

To create a long running activity, add a new item of type Workflow Element item to the project. Notice that the default activity inherits from CodeActivity.

To create complex activities such as long running activities, me need to change the base class and inherit from NativeActivity or NativeActivity<T>. In addition to that, there is a difference between the type of the parameter that the CodeActivity takes for the Execute method and the type that NativeActivity takes. Change the input parameter type from CodeActivityContext to ActivityExecutionContext.

Enter Bookmarks

In previous versions of Windows Workflow Foundation we had the ExternalDataExchangeService and WorkflowQueue when we wanted to build a simple long running activity. In WF 4.0 this is much more simple to do using Bookmarks.

To use bookmarks we need to:

• Create a named bookmark and Implement a callback method
• Signal from the caller program

Register a Named Bookmak

The following activity registers a bookmark called “input” with a callback method called OnBookmarkCallback.

Signal the workflow from the caller program

In a previous post I have talked about the code that is needed to execute a workflow. Since we are now talking about long running workflows we will start with the default code that is generated for us when we create a new sequential workflow console application that uses the WorkflowInstance that lets know when the workflow instance is idle, and to resume a bookmark:

The main program performs the input and delivers the value to the workflow. Using this approach:

• The main program is flexible in how it wants to get values from the user and any other input source
• The workflow becomes idle when it is waiting for the input and during that time not consuming any resources from the machine.

To query the available bookmarks in a workflow instance, we can use the following code:

Enjoy!

This is another post in my WF 4.0: Custom Activities series. In this post I’ll talk about creating a code only custom activity that performs a simple task. I’ll also use input and output parameters and talk about activities that returns a single value.

A Simple Code Activity

Lets start by building a simple activity that outputs a certain string to the console. To to that, lets add a new item of type Workflow Element (under the Workflow node in the item templates).

Visual Studio adds a new code file (remember – this is a code-only activity) with a class that inherits from the abstract class System.Activities.CodeActivity.

To implement the logic of the atomic action, we just have to code it here. Notice that we don’t have to tell the runtime that the status of this activity is closed or something like this like we had to in WF 3.5.

After building the project, the new custom activity will appear in the Toolbox, and can be used in the workflow.

Adding Input Parameters to the Custom Activity

To add a new input parameter to the activity, we declare a InArgument<T> field and property where T is the type of the parameter.

Note that in the property setter implementation I am calling the base class’ ThrowIfOpen() method. This method throws an InvalidOperationException if the activity has already been prepared for execution and the value cannot be set.

Also note that in order to get the property value, we do not store the value in a private member in the class, but instead – we use the InArgument class and using the Get method passing it the activity context.

Output Parameters to Custom Activities

Lets create a simple activity that reads the name from the console.

Notice how the code required for an output argument is similar to the one required for an input argument. Also notice how we set the value back to the output value using the ActivityContext instance.

Activities with a Single Output Parameter - CodeActivity<T>

The above sample read a string from the console and placed the value in the output parameter. If this is the case we can also inherit from CodeActivity<T>:

Inheriting from CodeActivity<T> makes it more simple to write a custom activity that has a single output parameter. It has additional benefits which I’ll talk about in a subsequent post.

Summary

In this post I talked about creating a code only custom activities that performs a simple task. I have also talked about input and output parameters.

Note: This post is based on Visual Studio 2010 Beta 1 which is the latest version available in the time of writing this post, so by the time this technology ships, there are probably things that will be slight different.

There are two ways to execute a workflow:

• Using the WorkflowInstance class
• Using the WorkflowInvoker class

Execute Workflows using WorkflowInstace

When you create a new Sequential Workflow Console Application, Visual Studio creates the basic code needed to execute the workflow inside the Main method:

1. A workflow instance is created and gets a reference to the root activity of the workflow. The WorkflowInstance class lets us control the running instance of the workflow and exposes several methods for this such as Run(), Abort(), Cancel(), Load(), Unload etc.

2. Since the workflow execution is scheduled to another thread, we need to block the main thread until the workflow is completed or terminated. To do this, we:

• Create an AutoResetEvent initialized to false,
• Set the event to true when the workflow is completed, and
• In the main thread - wait for the workflow to complete before exiting the method.

3. In order to handle errors in the workflow such as exceptions or termination, in addition to handling the OnCompleted event, we are also handling the OnHandledException and OnAborted events. Note that when the workflow has an unhandled exception, the program can still decide how it wants to end the workflow execution, whether it is by aborting, cancelling or terminating the workflow. If the workflow is terminated, the OnCompleted event will also be raised.

Execute Workflows using WorkflowInvoker

WorkflowInvoker lets you invoke a workflow much more easily than the previous approach. It takes the instance of the workflow or activity to run and executes it synchronously.

There are additional overloads of this method that takes parameters and a TimeSpan in which the workflow should complete within. I’ll talk in more details about passing parameters to workflow in a subsequent post, but in general this is all we have to know about WorkflowInvoker.

Choosing between WorkflowInstance and WorkflowInvoker

If you have a simple workflow that should run synchronously – use WorkflowInvoker. This is useful also in when unit testing workflows (more on this in a later post).

If you have a long running workflow that you want to control – persist, abort, cancel etc – use WorkflowInstance.

Enjoy!

Note: This post is based on Visual Studio 2010 Beta 1 which is the latest version available in the time of writing this post, so by the time this technology ships, there are probably things that will be slight different.

Start Visual Studio 2010 Beta 1 and create a new Sequential Workflow Console Application.

After you click OK, visual studio creates the new projects and creates a new WF project, in which there are some things you should know about:

References:

• System.Xaml – Now that there are several technologies based on Xaml, this is a new Assembly in .Net Framework 4.0 that contains Xaml services such as serialization.
• System.Activities is the assembly that contains the implementation of WF 4.0, and as you can guess, the corresponding namespace is System.Activities and anything beneath it.
• System.Activities.Design contains the designers for the activities and the designer re-hosting implementation. Since the new designer is based on WPF, you can also note references to WindowsBase, PresentationCode and PresentationFramework.
• System.ServiceModel contains WCF implementation (as of .Net Framework 3.0) and now System.ServiceModel.Activities contains the activities used for Workflow Services (the integration between WF and WCF).

Sequence.xaml:

By default, workflows are created declaratively in WF 4.0 and represented in .xaml files with no code behind. If you open this file with an Xml editor, you will see it clearly.

The new WF Designer shows an empty sequence, representing an empty block of execution. Note the warning sign that says that the sequence has no child activities.

From the Procedural section in the Toolbox, drag the WriteLine Activity to the design surface.

Now, you get a warning that the Text property is not set. To set it, go the properties window, and open the Expression Editor. In WF 4.0 you use the Expression to set values to variables and parameters, and you can use either static values (like in this case) or VB. Yes! Expression are written in VB.

Type the text you want to display to the console and click OK.

Now, that the simple workflow is completed, you can use Ctrl + F5 to run it like you normally do.

Debugging a Workflow

The debugging experience when debugging a workflow in WF 4.0 is very similar to the debugging experience when using code. You can right click an activity the in designer and select Insert Breakpoint, or use F9 to do this.

Once you do this and run the workflow, the debugger highlights the current activity using a yellow border (similar to the yellow background for the current statement when debugging code).

Enjoy!