第 79 页

and stepping through the execution in the same way you would any other Visual Studio project.

workinG with features

Features are primarily targeted at SharePoint

Administrators and provide them with a way to

manage related items. Every time you create an

item in a SharePoint project it is added to a Feature.

Features are stored under the Features node in

your SharePoint project. Visual Studio includes a

Feature Designer (shown in Figure 24-19), which

is displayed when you double-click a Feature.

The Feature Designer allows you to set a title and

description for the Feature that will be displayed

in SharePoint. You can also set the scope of the

Feature to an entire server farm, all web sites in a

site collection, a specific web site, or all web sites

in a web application.

You can choose to include or exclude certain

items in a Feature with the Feature Designer. For

example, in Figure 24-19, all SharePoint items in

the project except for MyWorkflow have been included in the Feature. If you have more than one

Feature in a project, you can also set dependencies that ensure one Feature cannot be activated

unless another Feature has been.

fiGure 24-18

fiGure 24-19

530 .

chaPter 24 ShArepoinT

In SharePoint, Administrators can activate or deactivate Features using the Manage Site Features

or Site Collection Features administration screens under Site Actions . Site Settings (see

Figure 24-20).

fiGure 24-20

PackaGinG and dePloyMent

SharePoint provides a custom packaging format called Windows SharePoint Package (WSP). WSP

files can contain Features, site definitions, templates and application pages, and additional required

assemblies. WSP files are created in the bin/debug or bin/release folder when you build a

SharePoint solution with Visual Studio. The WSP file can then be installed on a remote SharePoint

server by an administrator.

When you create a SharePoint project, a package definition file is also created in the project under

the Packages node. The package definition file describes what should go into the WSP file. Visual

Studio includes a Package Designer and Packaging Explorer tool window to assist with building

packages. If you double-click the package file it opens the file with these design tools. Figure 24-21

shows a package file that includes an application page and a single Feature.

When you press F5 in a SharePoint project, Visual Studio is saving you a whole lot of time by

automatically deploying all of the items in your project to the local SharePoint installation. The

deployment steps are specified under a SharePoint-specific project property page, shown in

Figure 24-22. To display this property page, right-click the project in the Solution Explorer and

select Properties.

Packaging and Deployment .

531

fiGure 24-21

fiGure 24-22

532 .

chaPter 24 ShArepoinT

You can specify a command-line program or script to run before and after Visual Studio deploys

the solution to the local SharePoint installation. The actual deployment steps are specified as a

deployment configuration. Double-click the configuration in the Edit Configurations list to display

the list of deployment steps. Figure 24-23 shows the default deployment configuration.

fiGure 24-23

Finally, you can right-click a project in the Solution Explorer and select Retract to remove the

SharePoint components from the local SharePoint installation.

suMMary

In this chapter you learned how to build solutions for Microsoft SharePoint 2010. The development

tools in Visual Studio 2010 allow you to easily develop Web Parts, workflows, custom lists, and

complete web applications that run under SharePoint’s rich hosting environment.

This chapter has just scratched the surface of what is possible with SharePoint 2010 development.

If you are interested in diving deeper into this topic, visit the SharePoint Developer Center

at http://msdn.microsoft.com/sharepoint, the SharePoint Dev Wiki at http://www

.sharepointdevwiki.com, or pick up a copy of Professional SharePoint 2010 Development

by Tom Rizzo, Reza Alirezaei, Jeff Fried, and Paul Swider.

25

Windows azure

what’s in this chaPter?

.

Understanding Windows Azure

.

Building, testing, and deploying applications using Windows Azure

.

Storing data in Windows Azure tables, blobs, and queues

.

Using SQL Azure from your application

.

Understanding the AppFabric

Over the past couple of years, the adoption of cloud computing has really taken off with

Google, Amazon, and a host of other providers entering the market. Microsoft’s approach

mirrors their own approach to desktop, mobile, and server computing, in so far as they are

offering a development platform on top of which both ISVs and Microsoft itself can build

great software. Without going into a formal definition of Cloud Computing, it is important to

recognize that you might choose to run your application in the cloud for a number of reasons.

These include the need for high availability, the ability to scale to meet the demand for your

application, and of course, cost reduction.

This chapter is broken into three sections that cover the Windows Azure Platform, SQL

Azure, and the AppFabric. The Windows Azure Platform hosts your web application, allowing

you to dynamically vary the number of concurrent instances running. It also provides storage

services in the form of tables, blobs, and queues. SQL Azure provides a true database service

hosted in the cloud. Finally, you can use the AppFabric to authenticate users, control access to

your application and services, and simplify the process of exposing services from within your

organization.

534 .

chaPter 25 WindoWS Azure

the windows azure PlatforM

As with most Microsoft technologies, getting started with the Windows Azure platform is as easy as

creating a new application, building it, and then running it. You will notice that there is a new node

in the New Project dialog entitled Cloud Service, which has a single project template, also called

Cloud Service, as shown in Figure 25-1.

fiGure 25-1

After selecting the Cloud Service project template you are prompted to add one or more Roles to

your application. An Azure project can be broken into different Roles based on the type of work

they are going to do and whether they accept user input. Simply put, Web Roles can accept user

input via an inbound connection (for example, http on port 80), whereas Worker Roles cannot. A

typical scenario would consist of a Web Role that is used to accept data. This may be a web site

or a web service of some description. The Web Role would hand off the data, for example, via a

queue, to a Worker Role, which would then

carry out any processing that is to be done.

This separation means that the two tiers can

be scaled out independently, improving the

elasticity of the application.

In Figure 25-2, both an ASP.NET Web

Role and a Worker Role have been added to

the cloud services solution by selecting the

role and clicking the right arrow button.

Clicking the edit symbol on the selected

role allows you to rename the role before

clicking OK to complete the creation of

your application. fiGure 25-2

The Windows azure Platform .

535

As you can see in Figure 25-3, the application created consists of

a project for each role selected (CloudFront and CloudWorker,

respectively) and an additional project, FirstCloudApplication, that

defines the list of roles and other information about your Azure

application.

The CloudFront project is essentially just an ASP.NET web application

project. In fact, if you right-click this project and select Set as Startup

Project you can run this project as with any normal ASP.NET project.

On the other hand, the CloudWorker project is simply a class library

with a single class, WorkerRole, which contains the entry point for the

worker.

To run your Azure application, make sure the FirstCloudApplication

project is set as the Startup Project and then press F5 to start

debugging. If this is your first time running an Azure application you

will notice a dialog appears that initializes the Development Storage.

This process takes a minute or two to complete; once done you will

notice that two icons have been added to the Windows taskbar.

The first allows you to control the Development Storage services, a set of three local services that

mirror the table, blob, and queue storage available in the Azure platform. The second allows you to

monitor the Development Fabric, a local replica of the Azure hosting environment in which you can

run, debug, and test your application.

After the Development Storage has been initialized you should notice that the Default.aspx

page of the

CloudFront project launches within the browser. Although you will only see a single browser instance,

in fact, multiple instances of the web role are all running in what’s called the Development Fabric.

the development fabric

In the FirstCloudApplication project are two files that define attributes about your Azure

application. The first, ServiceDefinition.csdef, defines the structure and attributes of the roles

that make up your application. For example, if one of your roles needs to write to the file system you

can stipulate a LocalStorage property, giving the role restricted access to a small amount of disk

space in which to read and write temporary files. This file also defines any settings that the roles will

require at run time. Defining settings is a great way to make your roles more adaptable at run time

without having to rebuild and publish them.

The second file is the ServiceConfiguration.cscfg file, which defines the run time configuration

of the roles. This includes the number of instances of each role that should be running, as well as

any settings that you have defined in the ServiceDefinition file. If you modify values in this

configuration file, for example, changing the count attribute of the Instances element to 4 for

both roles, and re-run your application, it will run with the new configuration values in the local

Development Fabric.

If you right-click the Development Fabric icon in the Windows taskbar and select Show

Development Fabric UI, you will see a hierarchical representation of the running applications within

the Development Fabric, as shown in Figure 25-4. As you drill down into the deployments you can

see the FirstCloudApplication and then the two roles, CloudFront and CloudWorker.

fiGure 25-3

536 .

chaPter 25 WindoWS Azure

fiGure 25-4

Within each of the roles you can see the number of running (green dot) instances, which in Figure 25-4

is 4. In the right pane you can see the log output for each of the running instances. Clicking the title

bar on any of the instances toggles that instance to display in the full pane. The icon in the top-right

corner of each instance indicates the logging level. You can adjust this by right-clicking the title and

selecting the desired value from the Logging Level menu item.

table, blob, and queue storage

So far you have a web role with no content and a worker role that doesn’t do anything. You can

add content to the web role by simply adding controls to the Default.aspx page in the same way

that you would for a normal web application. Start by adding a textbox called JobDetailsText and a

button called SubmitJob. Double-click the button to bring up the code-behind file.

You can pass data between web and worker roles by writing to table (structured data), blob (single

binary objects), or queue (messages) storage. You work with this storage within the Azure platform

via its REST interface. However, as .NET developers this is not a pleasant or efficient coding

experience. Luckily, the Azure team has put together a wrapper for this functionality that makes it

easy for your application to use Windows Azure storage. If you look at the references for both the

Web and Worker Role projects, you will see a reference for Microsoft.WindowsAzure.Storage.dll,

which contains the wrapper classes and methods that you can use from your application.

In the code-behind file for the Default.aspx page, enter the following code, which obtains a queue

reference and then adds a simple message. Note that you may need to add using statements to your

code file where necessary.

c#

protected void SubmitJob_Click(object sender, EventArgs e){

// read account configuration settings

var storageAccount = CloudStorageAccount.

FromConfigurationSetting("DataConnectionString");

The Windows azure Platform .

537

// create queue to communicate with worker role

var queueStorage = storageAccount.CreateCloudQueueClient();

var queue = queueStorage.GetQueueReference("sample");

queue.CreateIfNotExist();

queue.AddMessage(new CloudQueueMessage(this.JobDetailsText.Text));

}

Code snippet Default.aspx.cs

Vb

Protected Sub SubmitJob_Click(ByVal sender As Object,

ByVal e As EventArgs) Handles SubmitJob.Click

’ read account configuration settings

Dim storageAccount = CloudStorageAccount.

FromConfigurationSetting("DataConnectionString")

’ create queue to communicate with worker role

Dim queueStorage = storageAccount.CreateCloudQueueClient()

Dim queue = queueStorage.GetQueueReference("sample")

queue.CreateIfNotExist()

queue.AddMessage(New CloudQueueMessage(Me.JobDetailsText.Text))

End Sub

Code snippet Default.aspx.vb

This code takes the value supplied in the JobDetailsText textbox and adds it to the queue, wrapped

in as a message.

You also need to update the worker role to pop messages off the queue and carry out the appropriate

actions. The following code retrieves the next message on the queue, and simply writes the response

out to the log, before deleting the message off the queue. If you don’t delete the message from the

queue it is pushed back onto the queue after a configurable timeout, so as to ensure all messages are