Bug #17835


Net::HTTP should automatically add Accept-Encoding request header on HEAD request as well

Added by jrsyo (Shohei Maeda) 9 months ago. Updated about 2 months ago.

Target version:


Currently, Net::HTTP adds the Accept-Encoding request header by default except for HEAD method.

While this unlikely to cause any real-world problems, this isn't an ideal implementation according to the RFC below:

A server MAY send a Content-Length header field in a response to a
HEAD request (Section 4.3.2 of [RFC7231]); a server MUST NOT send
Content-Length in such a response unless its field-value equals the
decimal number of octets that would have been sent in the payload
body of a response if the same request had used the GET method.

Since server MAY (can) send the Content-Length header in response to a HEAD request, the client would see a Content-Length value of an uncompressed response if we don't send the Accept-Encoding request header.

$ curl -svo /dev/null '' -I --compressed 2>&1 | grep -i content-length
< content-length: 3380

$ curl -svo /dev/null '' -I 2>&1 | grep -i content-length
< content-length: 10932

Say, if the purpose of sending HEAD is to know the content-length beforehand (as an example) doesn’t it make sense to also add the Accept-Encoding request header on HEAD requests as well? In fact, users almost certainly request compressed objects in the subsequent requests (e.g., GET) because of the auto-addition logic above anyway.


Actions #1

Updated by jrsyo (Shohei Maeda) 9 months ago

  • Backport set to 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN
  • Tracker changed from Feature to Bug

Updated by hsbt (Hiroshi SHIBATA) about 2 months ago

  • Assignee set to naruse (Yui NARUSE)
  • Status changed from Open to Assigned was merged for Ruby 3.1.

But I'm not sure that we should backport this to Ruby 3.0 or old versions.


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