public override void OnResultExecuting(ResultExecutingContext context)
{
var cont = context.HttpContext;
if (cont == null)
{
return;
}
var encodings = context.HttpContext.Request.Headers[HeaderNames.AcceptEncoding];
var compressionType = CompressionUtils.GetType(encodings);
if (compressionType != CompressionUtils.CompressionType.Unknown)
{
var response = cont.Response;
switch (compressionType)
{
case CompressionUtils.CompressionType.Brotli:
response.Headers.Add(CustomCompressionHeader, "br");
break;
case CompressionUtils.CompressionType.GZip:
response.Headers.Add(CustomCompressionHeader, "gzip");
break;
case CompressionUtils.CompressionType.Deflate:
response.Headers.Add(CustomCompressionHeader, "deflate");
break;
}
}
base.OnResultExecuting(context);
}
public async Task Invoke(HttpContext context)
{
// store original response in a variable
Stream originalResponseBody = context.Response.Body;
using (var memStreamResponse = new MemoryStream())
using (var streamReaderResponse = new StreamReader(memStreamResponse))
{
// replace reponse body with an empty stream
context.Response.Body = memStreamResponse;
// set appropriate compression header
// (this is the only way to modify headers after the execution of response)
context.Response.OnStarting(state => {
var httpContext = (HttpContext)state;
var enconding = context.Response.Headers[CompressContentAttribute.CustomCompressionHeader];
if (enconding.Count > 0)
{
httpContext.Response.Headers[HeaderNames.ContentEncoding] = enconding;
httpContext.Response.Headers.Remove(CompressContentAttribute.CustomCompressionHeader);
}
return(Task.FromResult(0));
}, context);
await _next(context);
// set response body to its original value
context.Response.Body = originalResponseBody;
memStreamResponse.Position = 0;
string responseBody = await streamReaderResponse.ReadToEndAsync();
memStreamResponse.Position = 0;
var compressionType = CompressionUtils.GetType(context.Response.Headers[CompressContentAttribute.CustomCompressionHeader]);
if (compressionType != CompressionUtils.CompressionType.Unknown)
{
try
{
byte[] bytes;
switch (compressionType)
{
case CompressionUtils.CompressionType.Brotli:
bytes = CompressionUtils.Compress <BrotliStream>(responseBody);
break;
case CompressionUtils.CompressionType.GZip:
bytes = CompressionUtils.Compress <GZipStream>(responseBody);
break;
default: // case CompressionUtils.CompressionType.Deflate:
bytes = CompressionUtils.Compress <DeflateStream>(responseBody);
break;
}
await context.Response.Body.WriteAsync(bytes, 0, bytes.Length);
}
catch (Exception e)
{
// Checking for size prevents exceptions on cached static file requests...
if (!string.IsNullOrEmpty(responseBody))
{
await memStreamResponse.CopyToAsync(originalResponseBody);
}
context.Response.Body = originalResponseBody;
}
}
else
{
// Checking for size prevents exceptions on cached static file requests...
if (!string.IsNullOrEmpty(responseBody))
{
await memStreamResponse.CopyToAsync(originalResponseBody);
}
context.Response.Body = originalResponseBody;
}
}
}