broker

class broker.Broker(header_name='Accept')

Function dispatch based on MIME Accept-* headers.

Initialize a broker with some dispatched-to functions matched against MIME types:

>>> b = Broker()
>>> html_handler = b.add("text/html", lambda x: (1, x))
>>> xml_handler = b.add("application/xml", lambda x: (2, x))
>>> json_handler = b.add("application/json", lambda x: (3, x))

Select a backend function based on an Accept header:

>>> b.select("text/html") is html_handler
True
>>> b.select("text/html,application/json;q=0.1") is html_handler
True
>>> b.select("text/html;q=0.1,application/json") is json_handler
True

Call the backend functions directly:

>>> b("text/html", 'hello')
(1, 'hello')
>>> b("text/html,application/json;q=0.1", 'world')
(1, 'world')
>>> b("text/html;q=0.1,application/json", 'json_stuff')
(3, 'json_stuff')

add(mimetype, function, quality=1)

Register a function for a MIME type, optionally with a server quality.

Return the function directly. If quality is not provided, defaults to 1.

>>> b = Broker()
>>> _ = b.add('text/html', 'html_func')
>>> b.registry['text/html']
('html_func', 1)
>>> _ = b.add('application/json', 'json_func', quality=0.5)
>>> b.registry['application/json']
('json_func', 0.5)

register(mimetype, quality=1)

Build a decorator for registering a function for a MIME type.

>>> b = Broker()
>>> @b.register("text/html")
... def html_func(x):
...     return x + 1
>>> @b.register("application/json", quality=0.25)
... def json_func(x):
...     return x + 5
>>> b.registry['text/html']
(<function html_func at 0x...>, 1)
>>> b.registry['application/json']
(<function json_func at 0x...>, 0.25)

select(accept_header)

Get the best function for a given Accept header.

Raise NotAcceptable if no acceptable function is found.

>>> b = Broker()
>>> _ = b.add('text/html', 1)
>>> _ = b.add('application/json', 2)
>>> b.select('text/html')
1
>>> b.select('application/json')
2

server_types()

Return a list of (mimetype, quality) pairs, sorted by quality.

>>> b = Broker()
>>> b.add('application/json', None, quality=0.75)
>>> b.add('application/xml', None, quality=0.25)
>>> b.add('text/html', None, quality=1)
>>> b.server_types()
[('text/html', 1), ('application/json', 0.75), ('application/xml', 0.25)]