为 Azure Blob 存储启用 CORS

Question

I want to enable CORS in my Azure Blob Storage account. I am trying to follow this sample https://code.msdn.microsoft.com/Windows-Azure-Storage-CORS-45e5ce76

The server throws an System.Net.WebException (400) invalid request.

This is my code:

Global.asax.cs

    protected void Application_Start()
{
    Database.SetInitializer<dynazzy.Models.DAL>(null);
    AreaRegistration.RegisterAllAreas();

    WebApiConfig.Register(GlobalConfiguration.Configuration);
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);
    AzureCommon.InitializeAccountPropeties();
}

AzureCommon.cs

using System.Collections.Generic;
using Microsoft.WindowsAzure.Storage;
using Microsoft.WindowsAzure.Storage.Blob;
using Microsoft.WindowsAzure.Storage.Shared.Protocol;
using Microsoft.WindowsAzure.Storage.Table;
using Microsoft.WindowsAzure;

namespace dynazzy
{
    /// <summary>
    /// This class contains the Windows Azure Storage initialization and common functions.
    /// </summary>
    public class AzureCommon
    {
        private static CloudStorageAccount StorageAccount = CloudStorageAccount.DevelopmentStorageAccount;

        public static CloudBlobClient BlobClient
        {
            get;
            private set;
        }

        public static CloudTableClient TableClient
        {
            get;
            private set;
        }

        public static CloudBlobContainer ImagesContainer
        {
            get;
            private set;
        }

        public const string ImageContainerName = "someimagescontainer";

        /// <summary>
        /// Initialize Windows Azure Storage accounts and CORS settings.
        /// </summary>
        public static void InitializeAccountPropeties()
        {
            BlobClient = StorageAccount.CreateCloudBlobClient();
            TableClient = StorageAccount.CreateCloudTableClient();

            InitializeCors(BlobClient, TableClient);

            ImagesContainer = BlobClient.GetContainerReference(AzureCommon.ImageContainerName);
            ImagesContainer.CreateIfNotExists(BlobContainerPublicAccessType.Container);
        }

        /// <summary>
        /// Initialize Windows Azure Storage CORS settings.
        /// </summary>
        /// <param name="blobClient">Windows Azure storage blob client</param>
        /// <param name="tableClient">Windows Azure storage table client</param>
        private static void InitializeCors(CloudBlobClient blobClient, CloudTableClient tableClient)
        {
            // CORS should be enabled once at service startup
            ServiceProperties blobServiceProperties = new ServiceProperties();
            ServiceProperties tableServiceProperties = new ServiceProperties();

            // Nullifying un-needed properties so that we don't
            // override the existing ones
            blobServiceProperties.HourMetrics = null;
            tableServiceProperties.HourMetrics = null;
            blobServiceProperties.MinuteMetrics = null;
            tableServiceProperties.MinuteMetrics = null;
            blobServiceProperties.Logging = null;
            tableServiceProperties.Logging = null;

            // Enable and Configure CORS
            ConfigureCors(blobServiceProperties);
            ConfigureCors(tableServiceProperties);

            // Commit the CORS changes into the Service Properties
            blobClient.SetServiceProperties(blobServiceProperties);
            tableClient.SetServiceProperties(tableServiceProperties);
        }

        /// <summary>
        /// Adds CORS rule to the service properties.
        /// </summary>
        /// <param name="serviceProperties">ServiceProperties</param>
        private static void ConfigureCors(ServiceProperties serviceProperties)
        {
            serviceProperties.Cors = new CorsProperties();
            serviceProperties.Cors.CorsRules.Add(new CorsRule()
            {
                AllowedHeaders = new List<string>() { "*" },
                AllowedMethods = CorsHttpMethods.Put | CorsHttpMethods.Get | CorsHttpMethods.Head | CorsHttpMethods.Post,
                AllowedOrigins = new List<string>() { "*" },
                ExposedHeaders = new List<string>() { "*" },
                MaxAgeInSeconds = 1800 // 30 minutes
            });
        }
    }
}

WebApiConfig.cs

public static void Register(HttpConfiguration config)
{

    config.Routes.MapHttpRoute(
        name: "DefaultApi",
        routeTemplate: "api/{controller}/{id}",
        defaults: new { id = RouteParameter.Optional }
    );

}

Answer 1

To enable CORS, you need to set the appropriate service properties using version 2013-08-15 or later for the Blob, Queue, and Table services, or version 2015-02-21 or for the File service. You enable CORS by adding CORS rules to the service properties.

For details about how to enable or disable CORS for a service and how to set CORS rules, please refer to Set Blob Service Properties

Here is a sample of a single CORS rule, specified via a Set Service Properties operation:

<Cors>    
      <CorsRule>
            <AllowedOrigins>http://www.contoso.com, http://www.fabrikam.com</AllowedOrigins>
            <AllowedMethods>PUT,GET</AllowedMethods>
            <AllowedHeaders>x-ms-meta-data*,x-ms-meta-target*,x-ms-meta-abc</AllowedHeaders>
            <ExposedHeaders>x-ms-meta-*</ExposedHeaders>
            <MaxAgeInSeconds>200</MaxAgeInSeconds>
    </CorsRule>
<Cors>

Answer 2

After fighting with this for almost one day, I figured out that the error relates to an unsupported Azure Storage SDK version. I downgraded to version 3.0.2.0 of my Microsoft.WindowsAzure.Storage SDK and now I can talk to my Emulator.