/// <summary>
/// Finds all js and css files in a container and creates a gzip compressed
/// copy of the file with ".gzip" appended to the existing blob name
/// </summary>
public static void EnsureGzipFiles(
CloudBlobContainer container,
int cacheControlMaxAgeSeconds)
{
string cacheControlHeader = "public, max-age=" + cacheControlMaxAgeSeconds.ToString();
var blobInfos = container.ListBlobs(
new BlobRequestOptions()
{
UseFlatBlobListing = true
});
Parallel.ForEach(blobInfos, (blobInfo) =>
{
string blobUrl = blobInfo.Uri.ToString();
CloudBlob blob = container.GetBlobReference(blobUrl);
// only create gzip copies for css and js files
string extension = Path.GetExtension(blobInfo.Uri.LocalPath);
if (extension != ".css" && extension != ".js")
{
return;
}
// see if the gzip version already exists
string gzipUrl = blobUrl + ".gzip";
CloudBlob gzipBlob = container.GetBlobReference(gzipUrl);
if (gzipBlob.Exists())
{
return;
}
// create a gzip version of the file
using (MemoryStream memoryStream = new MemoryStream())
{
// push the original blob into the gzip stream
using (GZipStream gzipStream = new GZipStream(
memoryStream, CompressionMode.Compress, CompressionLevel.BestCompression))
using (BlobStream blobStream = blob.OpenRead())
{
blobStream.CopyTo(gzipStream);
}
// the gzipStream MUST be closed before its safe to read from the memory stream
byte[] compressedBytes = memoryStream.ToArray();
// upload the compressed bytes to the new blob
gzipBlob.UploadByteArray(compressedBytes);
// set the blob headers
gzipBlob.Properties.CacheControl = cacheControlHeader;
gzipBlob.Properties.ContentType = GetContentType(extension);
gzipBlob.Properties.ContentEncoding = "gzip";
gzipBlob.SetProperties();
}
});
}
public virtual void CopyTo(Stream output)
{
if (output == null)
{
throw new ArgumentNullException(nameof(output));
}
using (var blob = new BlobStream(this))
{
blob.CopyTo(output);
}
}
