Blob CORS Toggler

cors-toggler.bat

@echo off

D:\dev\path\to\ToggleCors.exe azuremap 123abcYourStorageKeyIsHere987zyx== %1

echo.
echo FOR COMPARISON QUERY THE nocors SERVICE (which never has CORS set)
echo.

D:\dev\path\to\ToggleCors.exe nocors 123abcYourStorageKeyIsHere987zyx== -q

echo.

PowerShell -Command Get-Date

SimpleAzureBlobCorsSetter.cs

using System;
using Microsoft.WindowsAzure.Storage.Auth;
using Microsoft.WindowsAzure.Storage.Blob;
using Microsoft.WindowsAzure.Storage.Shared.Protocol;
using Newtonsoft.Json;

namespace BlobCorsToggle
{
   public class SimpleAzureBlobCorsSetter
   {
      public CloudBlobClient CloudBlobClient { get; private set; }

      public SimpleAzureBlobCorsSetter(Uri blobServiceUri, StorageCredentials storageCredentials)
      {
         this.CloudBlobClient = new CloudBlobClient(blobServiceUri, storageCredentials);
      }

      public SimpleAzureBlobCorsSetter(CloudBlobClient blobClient)
      {
         this.CloudBlobClient = blobClient;
      }

      /// <summary>
      /// Set Blob Service CORS settings for specified Windows Azure Storage Account.
      /// Either sets to a hard-coded set of values (see below) or clears of all CORS settings.
      /// 
      /// Does not check for any existing CORS settings, but clobbers with the CORS settings
      /// to allow HTTP GET access from any origin. Non-CORS settings are left intact.
      /// 
      /// Most useful for scenarios where a file is published in Blob Storage for read-access
      /// by any client. 
      /// 
      /// Can also be useful in conjunction with Valet Key Pattern-style limited access, as
      /// might be useful with a mobile application.
      /// </summary>
      /// <param name="clear">if true, clears all CORS setting, else allows GET from any origin</param>
      public void SetBlobCorsGetAnyOrigin(bool clear)
      {
         // http://msdn.microsoft.com/en-us/library/windowsazure/dn535601.aspx
         var corsGetAnyOriginRule = new CorsRule();
         corsGetAnyOriginRule.AllowedOrigins.Add("*"); // allow access to any client
         corsGetAnyOriginRule.AllowedMethods = CorsHttpMethods.Get; // only CORS-enable http GET 
         corsGetAnyOriginRule.ExposedHeaders.Add("*"); // let client see any header we've configured
         corsGetAnyOriginRule.AllowedHeaders.Add("*"); // let clients request any header they can think of
         corsGetAnyOriginRule.MaxAgeInSeconds = (int)TimeSpan.FromHours(10).TotalSeconds; // clients are safe to cache CORS config for up to this long

         var blobServiceProperties = this.CloudBlobClient.GetServiceProperties();
         if (clear)
         {
            blobServiceProperties.Cors.CorsRules.Clear();
         }
         else
         {
            blobServiceProperties.Cors.CorsRules.Clear(); // replace current property set
            blobServiceProperties.Cors.CorsRules.Add(corsGetAnyOriginRule);
         }
         this.CloudBlobClient.SetServiceProperties(blobServiceProperties);
      }

      public void DumpCurrentProperties()
      {
         var blobServiceProperties = this.CloudBlobClient.GetServiceProperties();
         var blobPropertiesStringified = StringifyProperties(blobServiceProperties);
         Console.WriteLine("Current Properties:\n{0}", blobPropertiesStringified);
      }

      internal string StringifyProperties(ServiceProperties serviceProperties)
      {
         // JsonConvert.SerializeObject(serviceProperties) for whole object graph or
         // JsonConvert.SerializeObject(serviceProperties.Cors) for just CORS
         return Newtonsoft.Json.JsonConvert.SerializeObject(serviceProperties, Formatting.Indented);
      }
   }
}

ToggleCors.cs

using System;
using System.Diagnostics;
using System.IO;
using Microsoft.WindowsAzure.Storage.Auth;

namespace BlobCorsToggle
{
   class Program
   {
      static string clearFlag = "-clear";
      static string queryFlag = "-q";

      static void Main(string[] args)
      {
         if (args.Length == 0 || !ValidCommandArguments(args))
         {
            #region Show Correct Usage

            if (args.Length != 0 && !ValidCommandArguments(args))
            {
               var saveForegroundColor = Console.ForegroundColor;
               Console.ForegroundColor = ConsoleColor.Red;

               Console.Write("\nINVALID COMMAND LINE OR UNKNOWN FLAGS: ");
               foreach (var arg in args) Console.Write("{0} ", arg);
               Console.WriteLine();

               Console.ForegroundColor = saveForegroundColor;
            }

            Console.WriteLine("usage:\n{0} <storage acct name> <storage acct key> [{1}]",
               Path.GetFileNameWithoutExtension(Environment.GetCommandLineArgs()[0]),
               clearFlag);
            Console.WriteLine();
            Console.WriteLine("example setting:\n{0} {1} {2}",
               Path.GetFileNameWithoutExtension(Environment.GetCommandLineArgs()[0]),
               "mystorageacct",
               "lala+aou812SomERAndOmStrINglOlLolFroMmYStORaG3akounT314159265358979323ilIkEpi==");
            Console.WriteLine();
            Console.WriteLine("example clearing:\n{0} {1} {2} {3}",
               Path.GetFileNameWithoutExtension(Environment.GetCommandLineArgs()[0]),
               "mystorageacct",
               "lala+aou812SomERAndOmStrINglOlLolFroMmYStORaG3akounT314159265358979323ilIkEpi==",
               clearFlag);

            if (Debugger.IsAttached)
            {
               Console.WriteLine("\nPress any key to exit.");
               Console.ReadKey();
            }

            #endregion
         }
         else
         {
            var storageAccountName = args[0];
            var storageKey = args[1];

            var blobServiceUri = new Uri(String.Format("https://{0}.blob.core.windows.net", storageAccountName));
            var storageCredentials = new StorageCredentials(storageAccountName, storageKey);
            var blobConfig = new SimpleAzureBlobCorsSetter(blobServiceUri, storageCredentials);

            bool query = (args.Length == 3 && args[2] == queryFlag);
            if (query)
            {
               blobConfig.DumpCurrentProperties();
               return;
            }

            blobConfig.DumpCurrentProperties();
            Console.WriteLine();
            bool clear = (args.Length == 3 && args[2] == clearFlag);
            blobConfig.SetBlobCorsGetAnyOrigin(clear);
            Console.WriteLine("CORS Blob Properties for Storage Account {0} have been {1}.",
               storageAccountName, clear ? "cleared" : "set");
            Console.WriteLine();
            blobConfig.DumpCurrentProperties();
         }
      }

      private static bool ValidCommandArguments(string[] args)
      {
         if (args.Length == 2) return true;
         if (args.Length == 3 && (args[2] == clearFlag || args[2] == queryFlag)) return true;
         return false;
      }
   }
}