HTTP GET with Transfer-Encoding Chunked

0
votes

I recently saw a GET call which had the Transfer-Encoding header set to Chunked. What we noticed from this call is a delay then a 500 socket timeout.

Digging deeper, we showed this behavior of the 500 coming from ELB's and Apache web servers.

Of note, if we make the GET call with Transfer-Encoding as Chunked and include an empty payload, the ELB in our case allows the request to go through as normal.

Given this ELB's and Apache web servers exihibit this behaviour, my question is sending Transfer-Encoding as Chunked on a HTTP GET call is valid or not?

1
httphttpsamazon-elb

1 Answers

2
votes

The Transfer-Encoding header is now under authority of RFC 7230, section 3.3.1 (see also the IANA Message Header Registry. You will find that this header is part of the HTTP message framing, so it is valid for both, requests and responses.

Keeping in mind that GET requests may carry bodies, the reaction of the server(s) is absolutely correct. What is causing the delay followed by the 500 is probably the following: The server would expect a body but fails to find one, since the chunk-encoded representation of an empty string is not an empty string but a zero-sized chunk. In consequence, the server is running into a timeout.