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. For more information on the accept-language header, see RFC 7231, section-5.3.5

Usage

Install

% pip install content-negotiation

Getting started

Content type

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

Content language

from content_negotiation import decide_content_language, NoAgreeableContentLanguageError

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

Development

Requirements

• pyenv (recommended)
• python3
• pipx (recommended)
• poetry # version v1.2.0 or higher
• nox

% pipx install poetry==1.2.0
% pipx install nox==2022.8.7
% pipx inject nox nox-poetry==1.0.1

Install developer tools

% git clone https://github.com/Informasjonsforvaltning/content-negotiation.git
% cd content-negotiation
% pyenv install 3.8.13
% pyenv install 3.9.13
% pyenv install 3.10.6
% pyenv local 3.8.13 3.9.13 3.10.6
% poetry install

Run all sessions

% nox

Run all tests with coverage reporting

% nox -rs tests

Debugging

You can enter into Pdb by passing --pdb to pytest:

% nox -rs tests -- --pdb  --log-cli-level=DEBUG

You can set breakpoints directly in code by using the function breakpoint().