Add Cache-Control and Expires headers to Azure Storage Blobs

Question

I\'m using Azure Storage to serve up static file blobs but I\'d like to add a Cache-Control and Expires header to the files/blobs when served up to reduce bandwidth costs.

Answer 1

Here's an updated version of Joel Fillmore's answer consuming WindowsAzure.Storage v9.3.3. Note that ListBlobsSegmentedAsync returns a page size of 5,000 which is why the BlobContinuationToken is used.

    public async Task BackfillCacheControlAsync()
    {
        var container = await GetCloudBlobContainerAsync();
        BlobContinuationToken continuationToken = null;

        do
        {
            var blobInfos = await container.ListBlobsSegmentedAsync(string.Empty, true, BlobListingDetails.None, null, continuationToken, null, null);
            continuationToken = blobInfos.ContinuationToken;
            foreach (var blobInfo in blobInfos.Results)
            {
                var blockBlob = (CloudBlockBlob)blobInfo;
                var blob = await container.GetBlobReferenceFromServerAsync(blockBlob.Name);
                if (blob.Properties.CacheControl != "public, max-age=31536000")
                {
                    blob.Properties.CacheControl = "public, max-age=31536000";
                    await blob.SetPropertiesAsync();
                }
            }               
        }
        while (continuationToken != null);
    }

    private async Task GetCloudBlobContainerAsync()
    {
        var storageAccount = CloudStorageAccount.Parse(_appSettings.AzureStorageConnectionString);
        var blobClient = storageAccount.CreateCloudBlobClient();
        var container = blobClient.GetContainerReference("uploads");
        return container;
    }