HTTP Accept-Encoding and sending unencoded data

Question

I building a module for compressing HTTP output. Reading the spec, I haven't found a clear distinction on a couple of things:

Accept-Encoding:

Should this be treated the same as a Accept-Encoding: * or as if no header is present?

Or what if I don't support gzip, but I get a header like this:

Accept-Encoding: gzip

Should I return a 406 error or just return the data unencoded?

EDIT:

I've read over the spec a few times. It mentions my first case, but it doesn't define what the behavior of the server should be.

Should I treat this case as if the header is not present? Or should I return a 406 error because there's no way to encode something given the field value ('' isn't a valid encoding).

timaschew · Accepted Answer · 2011-07-15 00:02:57Z

8

There is written everything in the Spec: 14.3 Accept-Encoding:

The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header field.

If an Accept-Encoding field is present in a request, and if the server cannot send a response which is acceptable according to the Accept-Encoding header, then the server SHOULD send an error response with the 406 (Not Acceptable) status code.

edit:

If the Accept-Encoding field-value is empty, then only the "identity" encoding is acceptable.

In this case, if "identity" is one of the available content-codings, then the server SHOULD use the "identity" content-coding, unless it has additional information that a different content-coding is meaningful to the client.

What is "identity"

identity
The default (identity) encoding; the use of no transformation whatsoever. This content-coding is used only in the Accept- Encoding header, and SHOULD NOT be used in the Content-Encoding header.

edited Jul 15, 2011 at 0:02

answered Jul 14, 2011 at 23:46

timaschew

16.7k6 gold badges65 silver badges79 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

beatgammit Over a year ago

I think you missed my point. If I have an Accept-Encoding field, but it is empty, is that treated like a * symbol or should I return a 406 error?

beatgammit Over a year ago

If I have an Accept-Encoding field, but it is empty. Is that not clear? I don't think the spec specifies...

timaschew Over a year ago

Sorry, you are right, its late... But there is written something about the "identity" encoding, I edit my answer

beatgammit Over a year ago

What is the "identity" encoding? Does this mean whatever the file was initially without any change whatsoever?

timaschew Over a year ago

I think its the server default value, which you can set in the config of the webserver (apache for example)

|

Collectives™ on Stack Overflow

HTTP Accept-Encoding and sending unencoded data

1 Answer 1

6 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Related