HTTP response generator

httpgen.wsgi

#!/usr/bin/env python
"""
This simple service is aimed at web application developers. It allows them to
specify in the URL the HTTP response they want to get, in order to test the
behaviour of client codes.

The PATH_INFO is the desired status code, optionnally followed by a custom
message, e.g.:

  /200
  /404%20This%20is%20not%20the%20page%20you%20are%20looking%20for

Additionnal QUERY_STRING parameters can be used to add custom HTTP headers,
for example:

  /303?location=http://example.org/
  /401?www-authenticate=basic+realm=toto/

Note that, unless they are explicitly provided, the following headers will be
set with default values:

  content-type: text/plain
  access-control-allow-origin: *
  location: /200  (only when the status code is 3xx)
  

"""
from urlparse import parse_qs
from httplib import responses

def application(environ, start_response):
    path_info = environ['PATH_INFO']

    if path_info in ('', '/'):
        start_response("200 Ok", [
            ("content-type", "text/plain"),
            ])
        return [__doc__]

    try:
        status_int = int(path_info[1:4])
        status_str = path_info[1:]
        body = 'This is {PATH_INFO}\n'.format(**environ)
    except ValueError:
        status_int = -1
    if not (100 <= status_int <= 599):
        status_str = "404 Not found"
        body = ('You should require a valid HTTP code, '
                'e.g. {SCRIPT_NAME}/200\n').format(**environ)
    elif len(status_str) == 3:
        status_str = "{} {}".format(status_str, responses[status_int])

    custom_headers = parse_qs(environ['QUERY_STRING'])
    headers = [
            (key, val)
            for key, vals in custom_headers.items()
            for val in vals
        ]
    if 'content-type' not in custom_headers:
        headers.append(('content-type', 'text/plain'))
    if 'access-control-allow-origin' not in custom_headers:
        headers.append(('access-control-allow-origin', '*'))
    if status_int % 100 == 3:
        if 'location' not in custom_headers:
            headers.append(('location', '{SCRIPT_NAME}/200'.format(**environ)))

    start_response(status_str, headers)
    return [body]

if __name__ == "__main__":
    from wsgiref.simple_server import make_server
    httpd = make_server("localhost", 12345, application)
    httpd.serve_forever()