HTTP POST: content-length header required?

http post content-length http-content-length
Enrico 'nekrad' Weigelt picture Enrico 'nekrad' Weigelt · Feb 7, 2013 · Viewed 41.8k times · Source

I'm currently trying to optimize http-based data transfer between several applications. Our current approach, downloading first and then creating the post-request, obviously add extra IO/memory load and latencies, which I'd like to circumvent.

The core question of all:

Is it required to send a "Content-Length" header in HTTP POST requests? IIRC, HTTP 2616 declares that it's optional, but I'm not sure how applications actually behave at this point.

Answer

jdb picture jdb · Feb 7, 2013

Depends what you mean by optional. If you mean that you can just omit the header anytime you like then no, it is not optional. The HTTP spec has very specific rules when to use that header. There are different ways of sending the data if you don't know the length. Chunked encoding for example.

4.4 Message Length

Related questions

PUT vs. POST in REST

According to the HTTP/1.1 Spec: The POST method is used to request that the origin server accept the entity enclosed in the request as a new subordinate of the resource identified by the Request-URI in the Request-Line In other words, …

Read More
How are parameters sent in an HTTP POST request?

In an HTTP GET request, parameters are sent as a query string: http://example.com/page?parameter=value&also;=another In an HTTP POST request, the parameters are not sent along with the URI. Where are the values? In …

Read More
application/x-www-form-urlencoded or multipart/form-data?

In HTTP there are two ways to POST data: application/x-www-form-urlencoded and multipart/form-data. I understand that most browsers are only able to upload files if multipart/form-data is used. Is there any additional guidance when to use one of …

Read More