Reverting a URL in Flask to the endpoint + arguments

Question

What would be the appropriate way of resolving a URL within Flask to retrieve a reference to the endpoint as well as a dictionary of all the arguments?

To provide an example, given this route, I'd like to resolve '/user/nick' to profile,{'username': 'nick'}:

@app.route('/user/<username>')
def profile(username): pass

From my research so far, all routes in Flask are stored under app.url_map. The map is an instance of werkzeug.routing.Map and it has a method match() that would in principle do what I am looking for. However, that method is internal to the class.

Answer 1

This is what I hacked for this purpose looking at url_for() and reversing it:

from flask.globals import _app_ctx_stack, _request_ctx_stack
from werkzeug.urls import url_parse

def route_from(url, method = None):
    appctx = _app_ctx_stack.top
    reqctx = _request_ctx_stack.top
    if appctx is None:
        raise RuntimeError('Attempted to match a URL without the '
                           'application context being pushed. This has to be '
                           'executed when application context is available.')

    if reqctx is not None:
        url_adapter = reqctx.url_adapter
    else:
        url_adapter = appctx.url_adapter
        if url_adapter is None:
            raise RuntimeError('Application was not able to create a URL '
                               'adapter for request independent URL matching. '
                               'You might be able to fix this by setting '
                               'the SERVER_NAME config variable.')
    parsed_url = url_parse(url)
    if parsed_url.netloc is not "" and parsed_url.netloc != url_adapter.server_name:
        raise NotFound()
    return url_adapter.match(parsed_url.path, method)

The return value of this method is a tuple, with the first element being the endpoint name and the second a dictionary with the arguments.

I haven't tested it extensively, but it worked for me in all cases.

Answer 2

I know I am coming in late with an answer, but I ran into the same problem and found a simpler way to get it: request.view_args. For example:

In my views:

@app.route('/user/<username>')
def profile(username): 
    return render_template("profile.html")

In profile.html: {{request.view_args}}

When visiting the url http://localhost:4999/user/sam, I get: {'username': u'sam'}.

You can also get the name of the function that got your view with request.endpoint.