How do I make a trailing slash optional with webapp2?

Question

I\'m using the new webapp2 (now the default webapp in 1.6), and I haven\'t been able to figure out how to make the trailing slash optional in code like this:

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Answer 1

I was looking for a way to make the trailling slash on the root of a PathPrefixRoute block optional.

If you have, say:

from webapp2_extras.routes import RedirectRoute, PathPrefixRoute

from webapp2 import Route

app = webapp2.WSGIApplication([
  PathPrefixRoute('admin', [
      RedirectRoute('/', handler='DashboardHandler', name='admin-dashboard', strict_slash=True),
      RedirectRoute('/sample-page/', handler='SamplePageHandler', name='sample-page', strict_slash=True),
  ]),
])

You will be able to access /admin/, but not /admin.

Since I couldn't find any better solution, I've added a redirect_to_name to an extra route, like:

from webapp2_extras.routes import RedirectRoute, PathPrefixRoute

from webapp2 import Route

app = webapp2.WSGIApplication([
  Route('admin', handler='DashboardHandler', name='admin-dashboard'),
  PathPrefixRoute('admin', [
      RedirectRoute('/', redirect_to_name='admin-dashboard'),
      RedirectRoute('/sample-page/', handler='SamplePageHandler', name='sample-page', strict_slash=True),
  ]),
])

I'm interested in better solutions to this problem.

Should I go for Stun's solution and simply not use RedirectRoute?

Answer 2

I came up with a sort of hacky way. I define the following class:

class UrlConf(object):

    def __init__(self, *args, **kwargs):
        self.confs = []
        for arg in args:
            if isinstance(arg, webapp2.Route):
                slash_route = webapp2.Route(arg.template + '/', arg.handler)
                self.confs += [arg, slash_route]

    def __iter__(self):
        for route in self.confs:
            yield route

Then I set up my routes like the following:

MIRROR_URLS = list(UrlConf(
    Route('/path/to/stuff', handler=StuffHandler, name='stuff.page'),
    Route('/path/to/more/stuff', handler= MoreStuffHandler, name='more.stuff.page')
))

If you do choose to go this route, you can obviously improve upon it to be more flexible with other types of BaseRoute objects.

Answer 3

webapp2.Route template is not a regular expressions and your value is being escaped with re.escape. You can use old style rules which provides regular expression templates:

 webapp2.SimpleRoute('^/feed/?$', handler = feed)

Answer 4

To avoid creating duplicate URL:s to the same page, you should use a RedirectRoute with strict_slash set to True to automatically redirect /feed/ to /feed, like this:

from webapp2_extras.routes import RedirectRoute

route = RedirectRoute('/feed', handler=feed, strict_slash=True)

Read more at http://webapp2.readthedocs.io/en/latest/api/webapp2_extras/routes.html

Answer 5

If you don't want to use redirects (and you probably don't), you can override Route.match():

from webapp2 import Route, _get_route_variables
import urllib
from webob import exc


class SloppyRoute(Route):
    """
    A route with optional trailing slash.
    """
    def __init__(self, *args, **kwargs):
        super(SloppyRoute, self).__init__(*args, **kwargs)

    def match(self, request):
        path = urllib.unquote(request.path)
        match = self.regex.match(path)
        try:
            if not match and not path.endswith('/'):
                match = self.regex.match(path + '/')
        except:
            pass
        if not match or self.schemes and request.scheme not in self.schemes:
            return None

        if self.methods and request.method not in self.methods:
            # This will be caught by the router, so routes with different
            # methods can be tried.
            raise exc.HTTPMethodNotAllowed()

        args, kwargs = _get_route_variables(match, self.defaults.copy())
        return self, args, kwargs

Answer 6

I am not familiar with webapp2, but if the first parameter is a regular expression, try:

/feed(/)?