NoCaching Sample Code

The NoCaching sample code comprises the following items:

• NoCaching solution file

• AzureCloudService

• NoCaching.WebRole WebAPI project

• NoCaching class library

• Detailed Documentation

The NoCaching.WebRole WebAPI project contains two controllers:

• NoCacheController

• CacheController

The NoCacheController exposes a number of actions that retrieve data from the AdventureWorks2012 database. The information is fetched directly from the database (by using the Entity Framework) and is not cached. The following code snippet shows an example:

C#

public async Task<IHttpActionResult> GetPerson(int id)
{
    IPersonRepository repository = new PersonRepository();
    var person = await repository.GetAsync(id);

    if (person == null) return NotFound();
    return Ok(person);
}

The CacheController provides the same actions. The difference is that the code for these actions a different context class that implements the cache-aside pattern:

C#

public async Task<IHttpActionResult> GetPerson(int id)
{
    IPersonRepository repository = new CachedPersonRepository(new PersonRepository());
    var person = await repository.GetAsync(id);

    if (person == null) return NotFound();
    return Ok(person);
}

In this code snippet, the CachedPersonRepository class provides a wrapper around the PersonRepository class. The CachedPersonRepository class checks to see whether the requested information has been previously retrieved and cached, otherwise it uses a PersonRepository object to fetch the information from the database which is then added to the cache. The cache is implemented by using Azure Redis Cache:

C#

public class CachedPersonRepository : IPersonRepository
{
    private readonly PersonRepository _innerRepository;

    public CachedPersonRepository(PersonRepository innerRepository)
    {
        _innerRepository = innerRepository;
    }

    public async Task<Person> GetAsync(int id)
    {
        return await CacheService.GetAsync<Person>("p:" + id, () => _innerRepository.GetAsync(id)).ConfigureAwait(false);
    }
}

Configuring the project

This project uses the AdventureWorks2012 database stored by using Azure SQL Database. Create the database by using the Azure Management Portal and add the connection string to the AdventureWorksConnectionString setting in the ServiceConfiguration files for the AzureCloudService project.

Note that the new Azure portal provides a simplified version of the database (AdventureWorksLT). The AdventureWorksLT database uses a different schema from that expected by this sample application which might not function correctly unless the full AdventureWorks2012 database is installed.

This project also requires an instance of Azure Redis Cache. Create the cache by using the new Azure Portal and add the connection settings to the RedisConfiguration setting in the ServiceConfiguration files

Deploying the project to Azure

In Visual Studio Solution Explorer, right-click the AzureCloudService project and then click Publish to deploy the project to Azure.

Load testing the project

You can use Visual Studio Online to load test the application. For details of the load testing strategy for this sample, see Load Testing.

Dependencies

This project requires:

• Azure SDK 2.5

• An instance of the AdventureWorks2012 database

• An instance of Azure Redis Cache