gargant.dispatch

Flexible dispatcher for WSGI application.

Basic usage

Writing dispaching tree, and register wsgi apps to case:

from wsgiref.simple_server import make_server
from gargant.dispatch import Node, path_matching, make_wsgi_app

from path.to.yours import wsgi_app


tree = Node((path_matching(['']),),
            case=wsgi_app,
            name='first')

app = make_wsgi_app(tree)

httpd = make_server('', 8000, app)
httpb.serve_forever()

Registered app (wsgi_app) will be called when the path is '/'.

Node

gargant.dispatch is not just for creating a WSGI application. It can handle environ and return a value as you like.

You can apply anything to case:

>>> tree = Node((path_matching(['']),),
...             case='dolls')
>>>
>>> node = tree({'PATH_INFO': '/'})
>>> node.case  # 'dolls'

Hierarchy

Node class can take argument 'children' like this:

>>> tree = Node((path_matching(['']),),
...             case='dolls',
...             children=(
...                 Node((path_matching['fifth']),
...                      case='shinku'),
...             ))
>>>
>>> node = tree({'PATH_INFO': '/fifth'})
>>> node.case  # 'shinku'

There is not any matched children, the parent will be matched:

>>> node = tree({'PATH_INFO': '/'})
>>> node.case  # 'dolls'

Matching

path_matching is just one of matching patterns, you can use method_matching too:

>>> tree = Node((path_matching(['']),
                 method_matching('get')),
...             case='dolls',
...             )
>>>
>>> node = tree({'PATH_INFO': '/',
...              'REQUEST_METHOD': 'GET'})
>>> node.case  # 'dolls'

method patterns returns callables taking environ and return some values. All values returned from matchings can be handles as True. The Node will be handles as 'matched'.

Returned values from matchings will be store in node.matched as list of these.

URL args

And using this behavior, path_matching can take args from URL:

>>> tree = Node((path_matching(['']),),
...             case='doll_list',
...             children=(
...                 Node((path_matching(['{doll}']),),
...                       case='doll_detail',
...                 ),
...             ))
>>>
>>> node = tree({'PATH_INFO': '/first'})
>>> node.case  # 'doll_detail'
>>> node.matched[0]['doll']  # 'first'

Adapters

Node can take keyword arg named adapter_factory. It takes node.matched and return some callables you like:

>>> tree = Node((path_matching(['']),),
...             case='dolls',
...             children=(
...                 Node((path_matching(['fifth']),),
...                       case='shinku',
...                       adapter_factory=lambda matched: lambda x: x + ' kawaii'
...                 ),
...             ),
...             adapter_factory=lambda matched: lambda x: x + ' is'
...             )
>>>
>>> node = tree({'PATH_INFO': '/fifth'})
>>> node.case  # 'shinku'
>>> doll = 'shinku'
>>> root_to_leaf = reversed(list(node))  # [dolls node, shinku node]
>>> for node in root_to_leaf:
...     doll = node.adapter(doll)
...
>>> doll  # 'shinku is kawaii'

In this case, these adapter_factory will return simple functions, but gargant.dispatch is assuming you make it to return Adapter classes.