pyramid: Inverse to add_notfound_view(append_slash=True)

Question

In Pyramid, add_notfound_view(append_slash=True) will cause a request which does not match any view, but which would match a view if a trailing slash existed on the end, to be redirected to the matching view.

Does an inverse to this exist? That is: If I have a route configured as

config.add_route('list_reports', '/reports')

and a user requests /reports/, is there a simple way to cause them to be redirected appropriately?

Answer 1

The non-global solution

Add a second route for each view that you want redirected.

config = Configurator()
def add_auto_route(name, pattern, **kw):
    config.add_route(name, pattern, **kw)
    if not pattern.endswith('/'):
        config.add_route(name + '-auto', pattern + '/')
        def redirector(request):
            return HTTPMovedPermanently(request.route_url(name))
        config.add_view(redirector, route_name=name + '-auto')

add_auto_route('list_reports', '/reports')

Globally redirect all routes (never support slash-appended routes)

Simply rewrite the URLs. This can be done via pyramid_rewrite, or externally by your web server.

config = Configurator()
config.include('pyramid_rewrite')
config.add_rewrite_rule(r'/(?P<path>.*)/', r'/%(path)s')

Attempt to redirect if a route is not found

Rip the AppendSlashNotFoundFactory out of pyramid's source and invert it. Sorry, not doing that one for you here, but just as easy.

Answer 2

Michael's stuff is correct. Here's some code for the last case he didn't put code in for:

from pyramid.httpexceptions import default_exceptionresponse_view, HTTPFound
from pyramid.interfaces import IRoutesMapper

class RemoveSlashNotFoundViewFactory(object):
    def __init__(self, notfound_view=None):
        if notfound_view is None:
            notfound_view = default_exceptionresponse_view
        self.notfound_view = notfound_view

    def __call__(self, context, request):
        if not isinstance(context, Exception):
            # backwards compat for an append_notslash_view registered via
            # config.set_notfound_view instead of as a proper exception view
            context = getattr(request, 'exception', None) or context
        path = request.path
        registry = request.registry
        mapper = registry.queryUtility(IRoutesMapper)
        if mapper is not None and path.endswith('/'):
            noslash_path = path.rstrip('/')
            for route in mapper.get_routes():
                if route.match(noslash_path) is not None:
                    qs = request.query_string
                    if qs:
                        noslash_path += '?' + qs
                    return HTTPFound(location=noslash_path)
        return self.notfound_view(context, request)

Then in your main configuration:

config.add_notfound_view(RemoveSlashNotFoundViewFactory())