PipelineContinuation RewriteAppBase(ICommunicationContext ctx)
{
if (!ctx.Request.Headers.TryGetValue("forwarded", out var headerValue))
{
return(PipelineContinuation.Continue);
}
var header = ForwardedHeader.Parse(headerValue).FirstOrDefault();
if (header == null)
{
return(PipelineContinuation.Continue);
}
var appBaseUri = new UriBuilder(ctx.Request.Uri);
if (header.TryGetValue("host", out var host))
{
appBaseUri.Host = host;
}
var hasPort = header.TryGetValue("port", out var sport);
if (hasPort)
{
if (int.TryParse(sport, out var port))
{
appBaseUri.Port = port;
}
}
if (header.TryGetValue("proto", out var proto))
{
appBaseUri.Scheme = proto;
if (!hasPort)
{
appBaseUri.Port = -1;
}
}
if (header.TryGetValue("base", out var baseUri) && appBaseUri.Path.StartsWith(baseUri))
{
appBaseUri.Path = appBaseUri.Path.Substring(baseUri.Length);
}
ctx.Request.Uri = appBaseUri.Uri;
return(PipelineContinuation.Continue);
}
bool TryReadHeader(out ForwardedHeader header)
{
header = null;
while (TryReadPair(out var pair))
{
if (header == null)
{
header = new ForwardedHeader();
}
header[pair.key] = pair.value;
if (TryPeekChar(';'))
{
_pos++;
}
else
{
break;
}
}
return(header != null);
}