public override async Task Invoke(IOwinContext context)
{
var contextEnv = context.Environment;
Stream responseStream;
if (!contextEnv.ContainsKey(CommonOwinKeys.AdditionalInfo))
{
PushFunc pushPromise = null;
var path = context.Request.Path.Value;
var base64Req = path.Remove(0, 1); //remove leading /
var isHtmlReq = Regex.Match(base64Req, Base64Regex).Success;
var isJpeg = !isHtmlReq && path.EndsWith(TileExtension);
var url = String.Empty;
if (isHtmlReq)
{
var bingProcessor = new BingRequestProcessor(base64Req);
var images = bingProcessor.GetTilesSoapRequestsUrls();
foreach (var image in images.Where(image => TryGetPushPromise(context, out pushPromise)))
{
Push(context.Request, pushPromise, image);
}
url = BingRequestsUrl + base64Req;
}
else if (isJpeg)
{
url = BingRequestProcessor.GetSoapUrlFromTileName(path);
}
else
{
url = BingServiceUrl + path;
}
if (isHtmlReq)
{
var responseString = new WebClient().DownloadString(url); //html on original request
//TODO handle errors
HtmlProcessor.PreprocessHtml(ref responseString);
var response = Encoding.UTF8.GetBytes(responseString);
responseStream = context.Response.Body;
responseStream.Write(response, 0, response.Length);
}
else
{
DownloadVia11(url, context);
}
}
else
{
var url = context.Get <string>(CommonOwinKeys.AdditionalInfo);
DownloadVia11(url, context);
}
await Next.Invoke(context);
}
protected override void Push(IOwinRequest request, PushFunc pushPromise, string pushReference)
{
// Copy the headers
var headers = new HeaderDictionary(
new Dictionary <string, string[]>(request.Headers, StringComparer.OrdinalIgnoreCase));
// Populate special HTTP2 headers
headers[CommonHeaders.Method] = request.Method.ToUpper(); // TODO: Not all methods are allowed for push. Don't push, or change to GET?
headers[CommonHeaders.Scheme] = request.Scheme;
headers.Remove("Host");
headers[CommonHeaders.Authority] = request.Headers["Host"];
headers.Remove(CommonHeaders.ContentLength); // Push promises cannot emulate requests with bodies.
// TODO: What about cache headers? If-Match, If-None-Match, If-Modified-Since, If-Unmodified-Since.
// If-Match & If-None-Match are multi-value so the client could send e-tags for the primary resource and referenced resources.
// If-Modified-Since and If-Unmodified-Since are single value, so it may not make sense to apply them for secondary resources.
// Change the request path to the pushed resource
headers[CommonHeaders.Path] = pushReference;
pushPromise(headers);
}
public static void ReplaceDefault(PushFunc pushFunc, GetFunc getFunc)
{
Set = pushFunc;
Get = getFunc;
}
protected abstract void Push(IOwinRequest request, PushFunc pushPromise, string pushReference);
protected bool TryGetPushPromise(IOwinContext context, out PushFunc pushPromise)
{
pushPromise = context.Get <PushFunc>(CommonOwinKeys.ServerPushFunc);
return(pushPromise != null);
}
protected abstract void Push(IOwinRequest request, PushFunc pushPromise, string pushReference);
protected bool TryGetPushPromise(IOwinContext context, out PushFunc pushPromise)
{
pushPromise = context.Get<PushFunc>(CommonOwinKeys.ServerPushFunc);
return pushPromise != null;
}
protected override void Push(IOwinRequest request, PushFunc pushPromise, string pushReference)
{
request.Set(CommonOwinKeys.AdditionalInfo, pushReference);
// Copy the headers
var headers = new HeaderDictionary(
new Dictionary<string, string[]>(request.Headers, StringComparer.OrdinalIgnoreCase));
// Populate special HTTP2 headers
headers[CommonHeaders.Method] = request.Method;
// TODO: Not all methods are allowed for push. Don't push, or change to GET?
headers[CommonHeaders.Scheme] = request.Scheme;
headers.Remove("Host");
headers[CommonHeaders.Authority] = request.Headers["Host"];
headers[CommonHeaders.Path] = BingRequestProcessor.GetTileQuadFromSoapUrl(pushReference);
headers.Remove(CommonHeaders.ContentLength); // Push promises cannot emulate requests with bodies.
// TODO: What about cache headers? If-Match, If-None-Match, If-Modified-Since, If-Unmodified-Since.
// If-Match & If-None-Match are multi-value so the client could send e-tags for the primary resource and referenced resources.
// If-Modified-Since and If-Unmodified-Since are single value, so it may not make sense to apply them for secondary resources.
pushPromise(headers);
}
/// <summary>
/// Overrides request processing logic.
/// </summary>
/// <param name="stream">The stream.</param>
/// <param name="frame">The request header frame.</param>
/// <returns></returns>
protected override void ProcessRequest(Http2Stream stream, Frame frame)
{
/* 12 -> 8.1.3.1
* All HTTP/2 requests MUST include exactly one valid value for the
* ":method", ":scheme", and ":path" header fields, unless this is a
* CONNECT request (Section 8.3). An HTTP request that omits mandatory
* header fields is malformed (Section 8.1.3.5). */
if (stream.Headers.GetValue(CommonHeaders.Method) == null ||
stream.Headers.GetValue(CommonHeaders.Path) == null ||
stream.Headers.GetValue(CommonHeaders.Scheme) == null)
{
stream.WriteRst(ResetStatusCode.ProtocolError);
stream.Close(ResetStatusCode.ProtocolError);
return;
}
Task.Factory.StartNew(async() =>
{
try
{
var context = new Http2OwinMessageContext(stream);
var contextEnv = context.OwinContext.Environment;
PushFunc pushDelegate = null;
pushDelegate = async pairs =>
{
var promisedStream = CreateStream();
//assume that we have already received endStream
promisedStream.HalfClosedLocal = true;
stream.WritePushPromise(pairs, promisedStream.Id);
var headers = new HeadersList(pairs);
promisedStream.Headers.AddRange(headers);
var http2MsgCtx = new Http2OwinMessageContext(promisedStream);
var http2PushCtx = http2MsgCtx.OwinContext;
http2PushCtx.Set(CommonOwinKeys.ServerPushFunc, pushDelegate);
//pass add info from parent to child context. This info can store
//reference table for example or something els that should be passed from
//client request into child push requests.
if (contextEnv.ContainsKey(CommonOwinKeys.AdditionalInfo))
{
http2PushCtx.Set(CommonOwinKeys.AdditionalInfo, contextEnv[CommonOwinKeys.AdditionalInfo]);
}
await _next(http2PushCtx);
http2MsgCtx.FinishResponse();
};
context.OwinContext.Set(CommonOwinKeys.ServerPushFunc, pushDelegate);
context.OwinContext.Set(CommonOwinKeys.EnableServerPush, _isPushEnabled);
await _next(context.OwinContext);
context.FinishResponse();
}
catch (Exception ex)
{
EndResponse(stream, ex);
}
});
}
