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http-headerscontent-typehttp-accept-language

will Accept Http Headers digest any other formats other than the one specified?

Per my understanding:

the Accept header is used by HTTP clients to tell the server what content types they'll accept. The server will then send back a response, which will include a Content-Type header telling the client what the content type of the returned content actually is.

With this understanding, I tried the following:

curl -X GET -H "Accept: application/xml" http://www.google.com -v

* About to connect() to www.google.com port 80 (#0)
*   Trying 173.194.33.81...
* connected
* Connected to www.google.com (173.194.33.81) port 80 (#0)
> GET / HTTP/1.1
> User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8y zlib/1.2.5
> Host: www.google.com
> Accept: application/xml
> 
< HTTP/1.1 200 OK
< Date: Tue, 02 Sep 2014 17:58:05 GMT
< Expires: -1
< Cache-Control: private, max-age=0
< Content-Type: text/html; charset=ISO-8859-1
< Set-Cookie: PREF=ID=5c30672b67a74789:FF=0:TM=1409680685:LM=1409680685:S=PsGclk3vR4HWjann; expires=Thu, 01-Sep-2016 17:58:05 GMT; path=/; domain=.google.com
< Set-Cookie: NID=67=rPuxpwUu5UNuapzCdbD5iwVyjjC9TzP_Ado29h3ucjEq4A_2qkSM4nQM3RO02rfyuHmrh-hvmwmgFCmOvISttFfHv06f8ay4_6Gl4pXRjqxihNhJSGbvujjDRzaSibfy; expires=Wed, 04-Mar-2015 17:58:05 GMT; path=/; domain=.google.com; HttpOnly
< P3P: CP="This is not a P3P policy! See http://www.google.com/support/accounts/bin/answer.py?hl=en&answer=151657 for more info."
< Server: gws
< X-XSS-Protection: 1; mode=block
< X-Frame-Options: SAMEORIGIN
< Alternate-Protocol: 80:quic
< Transfer-Encoding: chunked
< 
<!doctype html><html itemscope="" itemtype="http://schema.org/WebPage" lang="en"><

As you can notice in the response, I am sent Content-Type: text/html; charset=ISO-8859-1 which is not what I asked for?

why does a different representation (HTML in this case) is sent, although I asked for xml?

Thanks

Solution

  • From RFC 2616:

    If an Accept header field is present, and if the server cannot send a response which is acceptable according to the combined Accept field value, then the server SHOULD send a 406 (not acceptable) response.

    Here, "should" means that Google aren't actually obliged to throw a 406 error. But since you're receiving an HTML response, it has effectively the same meaning.