Unclear how to determine allowed methods per URL, so hard to make a 405

[cdent]

When a URL exists, but does not support a particular method (e.g. DELETE) the correct response is to return an HTTP 405 response code. Routes doesn't make this immediately easy. By default a mapping that does not match just returns None with no indication that it was because of a failed condition after an initial path match. So what I've had to come up with is something like the following test, which seems cumbersome. Is there a better way?

from routes import Mapper, middleware

def test_405():
    map = Mapper()
    map.connect(
        '/controller/{id}', action='get_handler',
        conditions=dict(method=['GET', 'HEAD']))
    map.connect('/controller/{id}', action='post_handler',
        conditions=dict(method=['POST']))
    map.connect('/controller/{id}', action='405_handler')

    environ = {
        'PATH_INFO': '/controller/cow',
        'REQUEST_METHOD': 'GET',
        'SERVER_NAME': 'example.com',
        'SERVER_PORT': '80',
        'wsgi.url_scheme': 'http',
    }

    result = map.match(environ=environ)
    assert result['action'] == 'get_handler'

    environ['REQUEST_METHOD'] = 'POST'
    result = map.match(environ=environ)
    assert result['action'] == 'post_handler'

    environ['REQUEST_METHOD'] = 'PUT'
    result = map.match(environ=environ)
    assert result['action'] == '405_handler'

    environ['PATH_INFO'] = '/missed/url'
    result = map.match(environ=environ)
    assert result is None

[cdent]

This leaves out the mechanism whereby the 405_handler would know which methods to put in the Allow header of the response it sends.

[bbangert]

That's correct, it does not. In theory it could though, if it recorded the fact that a route did match, but then the method did not. I'd be open to a PR adding such a capability.

[cdent]

For reference the way I've ended up doing things is in the make_map() method in this file.

That's suitably explicit for my situation for now, but I'll keep thinking about a more general solution.

[bbangert]

I think having a special match method, or toggle that returns detailed match info would make it possible to handle this case. ie, instead of None, it'd return a Match object with information on what routes matched, and what checks failed. This way you could examine the object and determine if it was just the method that failed to match and issue a 405.

[bbangert]

Closing due to inactivity.