Content negotiation

A small Python library supporting content-negotiation.

It is used to decide content type based on a list of media ranges in the accept header, as well as deciding content-language based on the accept-language header.

  • Media ranges/language ranges with a q-value of 0.0 will be ignored.

  • Q-values above 1.0 will be treated as 1.0. Q-values below 0.0 will be treated as 0.0.

  • When a media range is not specified, it will be treated as /.

  • When a language range is not specified, it will be treated as *.

  • When media ranges and language ranges are equal, the first one will be returned.

For more information on the accept header, see [RFC 7231, section-5.3.2](https://tools.ietf.org/html/rfc7231#section-5.3.2).

For more information on the accept-language header, see [RFC 7231, section-5.3.5](https://www.rfc-editor.org/rfc/rfc7231#section-5.3.5)

Installation

To install the content-negotiation package, run this command in your terminal:

$ pip install content-negotiation

Usage

This package can be used like this:

from content_negotiation import decide_content_type, NoAgreeableContentTypeError

accept_headers = ["application/json", "text/html", "text/plain, text/*;q=0.8"]
supported_content_types = ["text/turtle", "application/json"]

try:
   content_type = decide_content_type(accept_headers, supported_content_types)
except NoAgreeableContentTypeError:
   print("No agreeable content type found.")
   # Handle error, by returning e.g. 406 Not Acceptable

from content_negotiation import decide_language, NoAgreeableLanguageError

accept_language_headers = ["en-GB;q=0.8", "nb-NO;q=0.9"]
supported_languages = ["en-GB", "en", "nb-NO", "nb", "en-US"]

try:
   content_language = decide_decide_language(accept_language_headers, supported_languages)
except NoAgreeableLanguageError:
   print("No agreeable language found.")
   # Handle error, by returning e.g. 406 Not Acceptable