Routes TODO¶
Updated 2009-09-07
Planned changes¶
Refactoring¶
Backport the Route
and Mapper
refactorings from Routes-experimental
(formerly called Routes 2). Make the objects more introspection-friendly.
Add a generation dict for named routes; this will help both efficiency and
introspection.
Generating the current URL with a modified query string¶
When url.current()
generates the current URL, it omits the existing query
string. Any keyword args passed override path variables or set new query
parameters. Extracting the existing query string from the request is tedious,
especially if you want to modify some parameters.
A new method url.current_with_query()
will generate the current URL with
its query string. Any keyword args add or override query parameters. An
argument with a value None
deletes that parameter if it exists, so that it
will not be in the generated URL. There will be no way to change path
variables in the URL.
Positional arguments will be appended to the URL path using urljoin.
Options for generating a fully-qualified URL will be retained. The option
_fragment
specifies a URL fragment (“#fragment”).
Failure routes¶
A method fail
for causing 4xx and 5xx errors. This is akin to
.redirect
for 3xx errors.
A convenience method gone
may also be added for 410 errors. This indicates
that the URL has been deleted and should be removed from bookmarks and
search engines. These will be called “gone routes”.
Chaining to WSGI applications¶
A connect argument wsgi_app
for chaining to another WSGI application.
This would allow a Pylons app to chain to other applications directly in the
route map rather than having to create dummy controllers for them.
Users would have to put “{path_info:.*}” at the end of the path to indicate which part of the URL should be passed to the application. This raises multiple issues:
- Users would prefer to specify a URL prefix rather than a URL with a path_info variable. But this is incompatible with Routes matching. One could create a special kind of route with a different method, such as
map.chain
, but that would raise as many issues as it solves, such as the need to duplicate all the route options in the second method.- What about the sub-application’s home page? I.e., PATH_INFO=/ . This can be handled by changing an empty path_info variable to “/”, but what if the route does not want a path_info variable in the path?
New route creation method¶
Add a new mapper method add
with a stricter syntax for creating routes.
(The existing connect
method will remain at least in all 1.x versions.)
map.add(name, path, variables=None, match=True, requirements=None,
if_match=None, if_function=None, if_subdomain=None, if_method=None,
generate_filter=None)
The first argument, name
is required. It should be a string name, or
None
for unnamed routes.
(This syntax is also allowed by connect
for forward compatibility.)
This eliminates the “moving argument” situation where the path
argument
changes position depending on whether a name is specified. This will make it
easier to read a list of route definitions aligned vertically, encourage named
routes, and make unnamed routes obvious.
The second argument, path
, is unchanged.
The third argument, variables
, is for extra variables. These will be
passed as a dict rather than as keyword args. This will make a clear
distinction between variables and route options, and allow options to have more
intuitive names without risk of collision, and without leading underscores.
New applications can use either the {}
or dict()
syntax; old
applications can simply put dict()
around existing keyword args. If no
extra variables are required you can pass an empty dict, None
, or omit the
argument.
The fourth argument, match
, is true if the route is for both matching and
generation, or false for generation only. The default is true. Whea
converting from connect
, change _static=True
to match=False
.
The remaining options should be set only via keyword arguments because their positions might change.
The requirements
option is unchanged.
if_function
corresponds to the function
condition in connect
. The
value is unchanged.
if_subdomain
corresponds to the subdomain
condition in connect
.
The value is unchanged.
if_method
corresponds to the method
condition in connect
. The
value is unchanged.
generate_filter
corresponds to the filter
argument to connect
.
The value is unchanged.
One problem is that users might expect this syntax in the redirect
method
(and fail
when it’s added), but redirect
can’t be changed due to
backward compatibility. Although some of these options may not make sense for
redirect and failure routes anyway. fail
is not so much an issue because
it doesn’t exist yet, so it doesn’t matter if it’s added with the new syntax.
Resource routes¶
Add a second kind of resource route with the traditional add-modify-delete
paradigm using only GET and POST, where each GET URL displays a form and the
same POST URL processes it. This is non-RESTful but useful in interactive
applications that don’t really need the other methods, and avoids doubling up
dissimilar behavior onto the same URL. The method should also have add=True,
edit=True, delete=True
arguments to disable services which will not be
implemented (e.g., resources that can’t be deleted, or are added outside the
web interface). This would be under a different method, hopefully called
something better than .resource2
.
Slimmed-down package¶
Make a slimmed-down version of Routes without deprecated features. This can be kept as a separate branch or repository, and uploaded to PyPI under Routes with a different filename; e.g., Routes-NC.
Under consideration¶
Route group¶
When adding a group of routes such as a resource, keep the group identity for
introspection. Currently the routes are added individually and lose their
groupness. This could be done with a RouteGroup
collection in the matchlist
which delegates to its sub-routes. This would not apply to named generation,
which needs a single dict of route names.
Required variables¶
A mapper constructor arg listing the variables all
routes must have in their path or extra variables. Defining a route without
these variables would raise an error. Intended for “controller” and “action”
variables in frameworks like Pylons. However, there are cases where
normally-required variables would be omitted, such as chaining to another WSGI
application (in which case “controller” would be necessary but not “action”).
Of course, the route can always define action=None
.