Configuring Azure storage

In some situations, it may be beneficial to store files of an on‑premise website on a Microsoft Azure Blob Storage account rather than on a local disk.

• For example, if your server has a limited storage capacity and you need to save large amounts of file data. Using Microsoft Azure may be more convenient than upgrading your server, especially if the increased requirements are only temporary.
• The same applies when running Kentico in Azure Web Apps, where use of blob storage is optional (unlike with Cloud Services).

Mapping files to Azure storage

To map media library folders to Azure storage, use the API and the built-in Azure storage provider:

1. Add the following keys to the appSettings section of your project’s web.config file. Specify the storage account name and primary access key:

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    <add key="CMSAzureAccountName" value="StorageAccountName" />
    <add key="CMSAzureSharedKey" value="PrimaryAccessKey" />
   
   
    

   To locate the values of these keys on Microsoft Azure:

   1. Open the Azure Management Portal in a browser and sign in.
   2. Open Storage accounts.
   3. Select your storage.
   4. Switch to the Access keys tab.
      • Use the Storage account name and one of the provided access key values.

2. If you are using the MVC development model, configure the same keys in the web.config of your MVC live site application.

3. Open the Kentico solution in Visual Studio (using the WebSite.sln or WebApp.sln file).

4. Create a custom module class. Add the class into a custom Class Library project within the solution.

   • For basic execution of initialization code, you only need to register a “code-only” module through the API. You do NOT need to create a new module within the Modules application in the Kentico administration interface.

5. Override the module’s OnInit method and perform the following:

   • Create a new instance of the Azure storage provider.
   • (Optional) Specify the target container using the CustomRootPath property of the provider.
   • (Optional) You can specify whether you want the container to be publicly accessible using the PublicExternalFolderObject property of the provider. True means the container is publicly accessible.
   • Map a directory to the provider. This is the directory that you want to store in the container.

using CMS;
using CMS.Base;
using CMS.DataEngine;
using CMS.IO;

// Registers the custom module into the system
[assembly: RegisterModule(typeof(CustomInitializationModule))]

public class CustomInitializationModule : Module
{
    // Module class constructor, the system registers the module under the name "CustomInit"
    public CustomInitializationModule()
        : base("CustomInit")
    {
    }

    // Contains initialization code that is executed when the application starts
    protected override void OnInit()
    {
        base.OnInit();

        // Creates a new StorageProvider instance for Azure
        var mediaProvider = StorageProvider.CreateAzureStorageProvider();

        // Specifies the target container
        mediaProvider.CustomRootPath = "mymediacontainer";

        // Makes the container publicly accessible
        mediaProvider.PublicExternalFolderObject = true;

        // Maps the local media library directory to the provider
        StorageHelper.MapStoragePath("~/MySite/Media/", mediaProvider);
    }
}

6. Save the file. If your project is installed in the web application format, rebuild the solution.
7. If you are utilizing the MVC development model, you also need to deploy the assembly containing the custom storage provider code to the separate MVC application (in addition to the Kentico administration project).

The system now stores files from the ~/MySite/Media/ folder in the mymediacontainer on the Azure storage. See the Media library notes section on this page for additional information about media libraries when using Azure storage.

Mapping files to storage accounts enforcing HTTPS connections

Some external storage accounts may enforce HTTPS communication via the Security transfer required setting configurable in the Azure portal. When mapping the file system or media library files to such accounts, you must include the CMSAzureBlobEndPoint configuration key in the application’s web.config file. The key’s value needs to contain the full endpoint URL of the external storage account and explicitly use the https protocol:

<appSettings>
    ...
    <add key="CMSAzureBlobEndPoint" value="https://_StorageAccountName_.blob.core.windows.net" />
</appSettings>

Media library notes

Using the Azure Blob storage as an external storage for your project has some specific effects on media libraries.

Storing too many files in one media library folder

Note that storing a large number of media files in a single folder can significantly affect the performance of user interface when editing files in the Media library application. The performance of the website, however, is not affected. See Media library limitations when storing files in an external storage for details.

Using permanent links when CMSAzurePublicContainer key is set to true

If all following conditions are true:

• you use the Azure Blob storage as an external storage
• and you set the CMSAzurePublicContainer key to true
• and you want to use content staging

then use Permanent links when linking to media files in media libraries.

The reason is that when using the CMSAzurePublicContainer key, direct file links contain the name of the storage in the URL. These links are not updated when staging files to another server, which is typically connected to a different storage. As a result, staged links incorrectly target files from the source server’s storage, or may become broken if the files are not exactly mirrored on the staging servers. Permanent links do not contain the name of the storage, and automatically target the correct storage for each server.

Optional web.config settings for Azure storage

<add key="CMSAzureTempPath" value="C:\AzureTemp" />

<add key="CMSAzureCachePath" value="C:\AzureCache" />

<add key="CMSAzureBlobEndPoint" value="http://127.0.0.1:10000/devstoreaccount1" />

<add key="CMSAzurePublicContainer" value="true" />

<add key="CMSAzureCDNEndpoint" value="kentico123.vo.msecnd.net" />

<add key="CMSDownloadBlobTimeout" value="50" />