Skip to content

Instantly share code, notes, and snippets.

@xiangzhuyuan

xiangzhuyuan/routing

Created October 14, 2012 14:18
Show Gist options
  • Save xiangzhuyuan/3888709 to your computer and use it in GitHub Desktop.
Save xiangzhuyuan/3888709 to your computer and use it in GitHub Desktop.
Download ZIP
Werkaeug routing
Raw
routing
# -*- coding: utf-8 -*-
"""
werkzeug.routing
~~~~~~~~~~~~~~~~
When it comes to combining multiple controller or view functions (however
you want to call them) you need a dispatcher. A simple way would be
applying regular expression tests on the ``PATH_INFO`` and calling
registered callback functions that return the value then.
This module implements a much more powerful system than simple regular
expression matching because it can also convert values in the URLs and
build URLs.
Here a simple example that creates an URL map for an application with
two subdomains (www and kb) and some URL rules:
>>> m = Map([
... # Static URLs
... Rule('/', endpoint='static/index'),
... Rule('/about', endpoint='static/about'),
... Rule('/help', endpoint='static/help'),
... # Knowledge Base
... Subdomain('kb', [
... Rule('/', endpoint='kb/index'),
... Rule('/browse/', endpoint='kb/browse'),
... Rule('/browse/<int:id>/', endpoint='kb/browse'),
... Rule('/browse/<int:id>/<int:page>', endpoint='kb/browse')
... ])
... ], default_subdomain='www')
If the application doesn't use subdomains it's perfectly fine to not set
the default subdomain and not use the `Subdomain` rule factory. The endpoint
in the rules can be anything, for example import paths or unique
identifiers. The WSGI application can use those endpoints to get the
handler for that URL. It doesn't have to be a string at all but it's
recommended.
Now it's possible to create a URL adapter for one of the subdomains and
build URLs:
>>> c = m.bind('example.com')
>>> c.build("kb/browse", dict(id=42))
'http://kb.example.com/browse/42/'
>>> c.build("kb/browse", dict())
'http://kb.example.com/browse/'
>>> c.build("kb/browse", dict(id=42, page=3))
'http://kb.example.com/browse/42/3'
>>> c.build("static/about")
'/about'
>>> c.build("static/index", force_external=True)
'http://www.example.com/'
>>> c = m.bind('example.com', subdomain='kb')
>>> c.build("static/about")
'http://www.example.com/about'
The first argument to bind is the server name *without* the subdomain.
Per default it will assume that the script is mounted on the root, but
often that's not the case so you can provide the real mount point as
second argument:
>>> c = m.bind('example.com', '/applications/example')
The third argument can be the subdomain, if not given the default
subdomain is used. For more details about binding have a look at the
documentation of the `MapAdapter`.
And here is how you can match URLs:
>>> c = m.bind('example.com')
>>> c.match("/")
('static/index', {})
>>> c.match("/about")
('static/about', {})
>>> c = m.bind('example.com', '/', 'kb')
>>> c.match("/")
('kb/index', {})
>>> c.match("/browse/42/23")
('kb/browse', {'id': 42, 'page': 23})
If matching fails you get a `NotFound` exception, if the rule thinks
it's a good idea to redirect (for example because the URL was defined
to have a slash at the end but the request was missing that slash) it
will raise a `RequestRedirect` exception. Both are subclasses of the
`HTTPException` so you can use those errors as responses in the
application.
If matching succeeded but the URL rule was incompatible to the given
method (for example there were only rules for `GET` and `HEAD` and
routing system tried to match a `POST` request) a `MethodNotAllowed`
method is raised.
:copyright: (c) 2010 by the Werkzeug Team, see AUTHORS for more details.
Thomas Johansson.
:license: BSD, see LICENSE for more details.
"""
import re
from pprint import pformat
from urlparse import urljoin
from itertools import izip
from werkzeug.urls import url_encode, url_quote
from werkzeug.utils import redirect, format_string
from werkzeug.exceptions import HTTPException, NotFound, MethodNotAllowed
from werkzeug._internal import _get_environ
_rule_re = re.compile(r'''
(?P<static>[^<]*) # static rule data
<
(?:
(?P<converter>[a-zA-Z_][a-zA-Z0-9_]*) # converter name
(?:\((?P<args>.*?)\))? # converter arguments
\: # variable delimiter
)?
(?P<variable>[a-zA-Z][a-zA-Z0-9_]*) # variable name
>
''', re.VERBOSE)
_simple_rule_re = re.compile(r'<([^>]+)>')
def parse_rule(rule):
"""Parse a rule and return it as generator. Each iteration yields tuples
in the form ``(converter, arguments, variable)``. If the converter is
`None` it's a static url part, otherwise it's a dynamic one.
:internal:
"""
pos = 0
end = len(rule)
do_match = _rule_re.match
used_names = set()
while pos < end:
m = do_match(rule, pos)
if m is None:
break
data = m.groupdict()
if data['static']:
yield None, None, data['static']
variable = data['variable']
converter = data['converter'] or 'default'
if variable in used_names:
raise ValueError('variable name %r used twice.' % variable)
used_names.add(variable)
yield converter, data['args'] or None, variable
pos = m.end()
if pos < end:
remaining = rule[pos:]
if '>' in remaining or '<' in remaining:
raise ValueError('malformed url rule: %r' % rule)
yield None, None, remaining
def get_converter(map, name, args):
"""Create a new converter for the given arguments or raise
exception if the converter does not exist.
:internal:
"""
if not name in map.converters:
raise LookupError('the converter %r does not exist' % name)
if args:
storage = type('_Storage', (), {'__getitem__': lambda s, x: x})()
args, kwargs = eval(u'(lambda *a, **kw: (a, kw))(%s)' % args, {}, storage)
else:
args = ()
kwargs = {}
return map.converters[name](map, *args, **kwargs)
class RoutingException(Exception):
"""Special exceptions that require the application to redirect, notifying
about missing urls, etc.
:internal:
"""
class RequestRedirect(HTTPException, RoutingException):
"""Raise if the map requests a redirect. This is for example the case if
`strict_slashes` are activated and an url that requires a trailing slash.
The attribute `new_url` contains the absolute destination url.
"""
code = 301
def __init__(self, new_url):
RoutingException.__init__(self, new_url)
self.new_url = new_url
def get_response(self, environ):
return redirect(self.new_url, 301)
class RequestSlash(RoutingException):
"""Internal exception."""
class BuildError(RoutingException, LookupError):
"""Raised if the build system cannot find a URL for an endpoint with the
values provided.
"""
def __init__(self, endpoint, values, method):
LookupError.__init__(self, endpoint, values, method)
self.endpoint = endpoint
self.values = values
self.method = method
class ValidationError(ValueError):
"""Validation error. If a rule converter raises this exception the rule
does not match the current URL and the next URL is tried.
"""
class RuleFactory(object):
"""As soon as you have more complex URL setups it's a good idea to use rule
factories to avoid repetitive tasks. Some of them are builtin, others can
be added by subclassing `RuleFactory` and overriding `get_rules`.
"""
def get_rules(self, map):
"""Subclasses of `RuleFactory` have to override this method and return
an iterable of rules."""
raise NotImplementedError()
class Subdomain(RuleFactory):
"""All URLs provided by this factory have the subdomain set to a
specific domain. For example if you want to use the subdomain for
the current language this can be a good setup::
url_map = Map([
Rule('/', endpoint='#select_language'),
Subdomain('<string(length=2):lang_code>', [
Rule('/', endpoint='index'),
Rule('/about', endpoint='about'),
Rule('/help', endpoint='help')
])
])
All the rules except for the ``'#select_language'`` endpoint will now
listen on a two letter long subdomain that holds the language code
for the current request.
"""
def __init__(self, subdomain, rules):
self.subdomain = subdomain
self.rules = rules
def get_rules(self, map):
for rulefactory in self.rules:
for rule in rulefactory.get_rules(map):
rule = rule.empty()
rule.subdomain = self.subdomain
yield rule
class Submount(RuleFactory):
"""Like `Subdomain` but prefixes the URL rule with a given string::
url_map = Map([
Rule('/', endpoint='index'),
Submount('/blog', [
Rule('/', endpoint='blog/index'),
Rule('/entry/<entry_slug>', endpoint='blog/show')
])
])
Now the rule ``'blog/show'`` matches ``/blog/entry/<entry_slug>``.
"""
def __init__(self, path, rules):
self.path = path.rstrip('/')
self.rules = rules
def get_rules(self, map):
for rulefactory in self.rules:
for rule in rulefactory.get_rules(map):
rule = rule.empty()
rule.rule = self.path + rule.rule
yield rule
class EndpointPrefix(RuleFactory):
"""Prefixes all endpoints (which must be strings for this factory) with
another string. This can be useful for sub applications::
url_map = Map([
Rule('/', endpoint='index'),
EndpointPrefix('blog/', [Submount('/blog', [
Rule('/', endpoint='index'),
Rule('/entry/<entry_slug>', endpoint='show')
])])
])
"""
def __init__(self, prefix, rules):
self.prefix = prefix
self.rules = rules
def get_rules(self, map):
for rulefactory in self.rules:
for rule in rulefactory.get_rules(map):
rule = rule.empty()
rule.endpoint = self.prefix + rule.endpoint
yield rule
class RuleTemplate(object):
"""Returns copies of the rules wrapped and expands string templates in
the endpoint, rule, defaults or subdomain sections.
Here a small example for such a rule template::
from werkzeug.routing import Map, Rule, RuleTemplate
resource = RuleTemplate([
Rule('/$name/', endpoint='$name.list'),
Rule('/$name/<int:id>', endpoint='$name.show')
])
url_map = Map([resource(name='user'), resource(name='page')])
When a rule template is called the keyword arguments are used to
replace the placeholders in all the string parameters.
"""
def __init__(self, rules):
self.rules = list(rules)
def __call__(self, *args, **kwargs):
return RuleTemplateFactory(self.rules, dict(*args, **kwargs))
class RuleTemplateFactory(RuleFactory):
"""A factory that fills in template variables into rules. Used by
`RuleTemplate` internally.
:internal:
"""
def __init__(self, rules, context):
self.rules = rules
self.context = context
def get_rules(self, map):
for rulefactory in self.rules:
for rule in rulefactory.get_rules(map):
new_defaults = subdomain = None
if rule.defaults is not None:
new_defaults = {}
for key, value in rule.defaults.iteritems():
if isinstance(value, basestring):
value = format_string(value, self.context)
new_defaults[key] = value
if rule.subdomain is not None:
subdomain = format_string(rule.subdomain, self.context)
new_endpoint = rule.endpoint
if isinstance(new_endpoint, basestring):
new_endpoint = format_string(new_endpoint, self.context)
yield Rule(
format_string(rule.rule, self.context),
new_defaults,
subdomain,
rule.methods,
rule.build_only,
new_endpoint,
rule.strict_slashes
)
class Rule(RuleFactory):
"""A Rule represents one URL pattern. There are some options for `Rule`
that change the way it behaves and are passed to the `Rule` constructor.
Note that besides the rule-string all arguments *must* be keyword arguments
in order to not break the application on Werkzeug upgrades.
`string`
Rule strings basically are just normal URL paths with placeholders in
the format ``<converter(arguments):name>`` where the converter and the
arguments are optional. If no converter is defined the `default`
converter is used which means `string` in the normal configuration.
URL rules that end with a slash are branch URLs, others are leaves.
If you have `strict_slashes` enabled (which is the default), all
branch URLs that are matched without a trailing slash will trigger a
redirect to the same URL with the missing slash appended.
The converters are defined on the `Map`.
`endpoint`
The endpoint for this rule. This can be anything. A reference to a
function, a string, a number etc. The preferred way is using a string
because the endpoint is used for URL generation.
`defaults`
An optional dict with defaults for other rules with the same endpoint.
This is a bit tricky but useful if you want to have unique URLs::
url_map = Map([
Rule('/all/', defaults={'page': 1}, endpoint='all_entries'),
Rule('/all/page/<int:page>', endpoint='all_entries')
])
If a user now visits ``http://example.com/all/page/1`` he will be
redirected to ``http://example.com/all/``. If `redirect_defaults` is
disabled on the `Map` instance this will only affect the URL
generation.
`subdomain`
The subdomain rule string for this rule. If not specified the rule
only matches for the `default_subdomain` of the map. If the map is
not bound to a subdomain this feature is disabled.
Can be useful if you want to have user profiles on different subdomains
and all subdomains are forwarded to your application::
url_map = Map([
Rule('/', subdomain='<username>', endpoint='user/homepage'),
Rule('/stats', subdomain='<username>', endpoint='user/stats')
])
`methods`
A sequence of http methods this rule applies to. If not specified, all
methods are allowed. For example this can be useful if you want different
endpoints for `POST` and `GET`. If methods are defined and the path
matches but the method matched against is not in this list or in the
list of another rule for that path the error raised is of the type
`MethodNotAllowed` rather than `NotFound`. If `GET` is present in the
list of methods and `HEAD` is not, `HEAD` is added automatically.
.. versionchanged:: 0.6.1
`HEAD` is now automatically added to the methods if `GET` is
present. The reason for this is that existing code often did not
work properly in servers not rewriting `HEAD` to `GET`
automatically and it was not documented how `HEAD` should be
treated. This was considered a bug in Werkzeug because of that.
`strict_slashes`
Override the `Map` setting for `strict_slashes` only for this rule. If
not specified the `Map` setting is used.
`build_only`
Set this to True and the rule will never match but will create a URL
that can be build. This is useful if you have resources on a subdomain
or folder that are not handled by the WSGI application (like static data)
`redirect_to`
If given this must be either a string or callable. In case of a
callable it's called with the url adapter that triggered the match and
the values of the URL as keyword arguments and has to return the target
for the redirect, otherwise it has to be a string with placeholders in
rule syntax::
def foo_with_slug(adapter, id):
# ask the database for the slug for the old id. this of
# course has nothing to do with werkzeug.
return 'foo/' + Foo.get_slug_for_id(id)
url_map = Map([
Rule('/foo/<slug>', endpoint='foo'),
Rule('/some/old/url/<slug>', redirect_to='foo/<slug>'),
Rule('/other/old/url/<int:id>', redirect_to=foo_with_slug)
])
When the rule is matched the routing system will raise a
`RequestRedirect` exception with the target for the redirect.
Keep in mind that the URL will be joined against the URL root of the
script so don't use a leading slash on the target URL unless you
really mean root of that domain.
"""
def __init__(self, string, defaults=None, subdomain=None, methods=None,
build_only=False, endpoint=None, strict_slashes=None,
redirect_to=None):
if not string.startswith('/'):
raise ValueError('urls must start with a leading slash')
self.rule = string
self.is_leaf = not string.endswith('/')
self.map = None
self.strict_slashes = strict_slashes
self.subdomain = subdomain
self.defaults = defaults
self.build_only = build_only
if methods is None:
self.methods = None
else:
self.methods = set([x.upper() for x in methods])
if 'HEAD' not in self.methods and 'GET' in self.methods:
self.methods.add('HEAD')
self.endpoint = endpoint
self.greediness = 0
self.redirect_to = redirect_to
if defaults is not None:
self.arguments = set(map(str, defaults))
else:
self.arguments = set()
self._trace = self._converters = self._regex = self._weights = None
def empty(self):
"""Return an unbound copy of this rule. This can be useful if you
want to reuse an already bound URL for another map."""
defaults = None
if self.defaults is not None:
defaults = dict(self.defaults)
return Rule(self.rule, defaults, self.subdomain, self.methods,
self.build_only, self.endpoint, self.strict_slashes,
self.redirect_to)
def get_rules(self, map):
yield self
def refresh(self):
"""Rebinds and refreshes the URL. Call this if you modified the
rule in place.
:internal:
"""
self.bind(self.map, rebind=True)
def bind(self, map, rebind=False):
"""Bind the url to a map and create a regular expression based on
the information from the rule itself and the defaults from the map.
:internal:
"""
if self.map is not None and not rebind:
raise RuntimeError('url rule %r already bound to map %r' %
(self, self.map))
self.map = map
if self.strict_slashes is None:
self.strict_slashes = map.strict_slashes
if self.subdomain is None:
self.subdomain = map.default_subdomain
rule = self.subdomain + '|' + (self.is_leaf and self.rule
or self.rule.rstrip('/'))
self._trace = []
self._converters = {}
self._weights = []
regex_parts = []
for converter, arguments, variable in parse_rule(rule):
if converter is None:
regex_parts.append(re.escape(variable))
self._trace.append((False, variable))
self._weights.append(len(variable))
else:
convobj = get_converter(map, converter, arguments)
regex_parts.append('(?P<%s>%s)' % (variable, convobj.regex))
self._converters[variable] = convobj
self._trace.append((True, variable))
self._weights.append(convobj.weight)
self.arguments.add(str(variable))
if convobj.is_greedy:
self.greediness += 1
if not self.is_leaf:
self._trace.append((False, '/'))
if not self.build_only:
regex = r'^%s%s$' % (
u''.join(regex_parts),
(not self.is_leaf or not self.strict_slashes) and \
'(?<!/)(?P<__suffix__>/?)' or ''
)
self._regex = re.compile(regex, re.UNICODE)
def match(self, path):
"""Check if the rule matches a given path. Path is a string in the
form ``"subdomain|/path(method)"`` and is assembled by the map.
If the rule matches a dict with the converted values is returned,
otherwise the return value is `None`.
:internal:
"""
if not self.build_only:
m = self._regex.search(path)
if m is not None:
groups = m.groupdict()
# we have a folder like part of the url without a trailing
# slash and strict slashes enabled. raise an exception that
# tells the map to redirect to the same url but with a
# trailing slash
if self.strict_slashes and not self.is_leaf and \
not groups.pop('__suffix__'):
raise RequestSlash()
# if we are not in strict slashes mode we have to remove
# a __suffix__
elif not self.strict_slashes:
del groups['__suffix__']
result = {}
for name, value in groups.iteritems():
try:
value = self._converters[name].to_python(value)
except ValidationError:
return
result[str(name)] = value
if self.defaults is not None:
result.update(self.defaults)
return result
def build(self, values, append_unknown=True):
"""Assembles the relative url for that rule and the subdomain.
If building doesn't work for some reasons `None` is returned.
:internal:
"""
tmp = []
add = tmp.append
processed = set(self.arguments)
for is_dynamic, data in self._trace:
if is_dynamic:
try:
add(self._converters[data].to_url(values[data]))
except ValidationError:
return
processed.add(data)
else:
add(data)
subdomain, url = (u''.join(tmp)).split('|', 1)
if append_unknown:
query_vars = MultiDict(values)
for key in processed:
if key in query_vars:
del query_vars[key]
if query_vars:
url += '?' + url_encode(query_vars, self.map.charset,
sort=self.map.sort_parameters,
key=self.map.sort_key)
return subdomain, url
def provides_defaults_for(self, rule):
"""Check if this rule has defaults for a given rule.
:internal:
"""
return not self.build_only and self.defaults is not None and \
self.endpoint == rule.endpoint and self != rule and \
self.arguments == rule.arguments
def suitable_for(self, values, method=None):
"""Check if the dict of values has enough data for url generation.
:internal:
"""
if method is not None:
if self.methods is not None and method not in self.methods:
return False
valueset = set(values)
for key in self.arguments - set(self.defaults or ()):
if key not in values:
return False
if self.arguments.issubset(valueset):
if self.defaults is None:
return True
for key, value in self.defaults.iteritems():
if value != values[key]:
return False
return True
def match_compare(self, other):
"""Compare this object with another one for matching.
:internal:
"""
for sw, ow in izip(self._weights, other._weights):
if sw > ow:
return -1
elif sw < ow:
return 1
if len(self._weights) > len(other._weights):
return -1
if len(self._weights) < len(other._weights):
return 1
if not other.arguments and self.arguments:
return 1
elif other.arguments and not self.arguments:
return -1
elif other.defaults is None and self.defaults is not None:
return 1
elif other.defaults is not None and self.defaults is None:
return -1
elif self.greediness > other.greediness:
return -1
elif self.greediness < other.greediness:
return 1
elif len(self.arguments) > len(other.arguments):
return 1
elif len(self.arguments) < len(other.arguments):
return -1
return 1
def build_compare(self, other):
"""Compare this object with another one for building.
:internal:
"""
if not other.arguments and self.arguments:
return -1
elif other.arguments and not self.arguments:
return 1
elif other.defaults is None and self.defaults is not None:
return -1
elif other.defaults is not None and self.defaults is None:
return 1
elif self.provides_defaults_for(other):
return -1
elif other.provides_defaults_for(self):
return 1
elif self.greediness > other.greediness:
return -1
elif self.greediness < other.greediness:
return 1
elif len(self.arguments) > len(other.arguments):
return -1
elif len(self.arguments) < len(other.arguments):
return 1
return -1
def __eq__(self, other):
return self.__class__ is other.__class__ and \
self._trace == other._trace
def __ne__(self, other):
return not self.__eq__(other)
def __unicode__(self):
return self.rule
def __str__(self):
charset = self.map is not None and self.map.charset or 'utf-8'
return unicode(self).encode(charset)
def __repr__(self):
if self.map is None:
return '<%s (unbound)>' % self.__class__.__name__
charset = self.map is not None and self.map.charset or 'utf-8'
tmp = []
for is_dynamic, data in self._trace:
if is_dynamic:
tmp.append('<%s>' % data)
else:
tmp.append(data)
return '<%s %r%s -> %s>' % (
self.__class__.__name__,
(u''.join(tmp).encode(charset)).lstrip('|'),
self.methods is not None and ' (%s)' % \
', '.join(self.methods) or '',
self.endpoint
)
class BaseConverter(object):
"""Base class for all converters."""
regex = '[^/]+'
is_greedy = False
weight = 100
def __init__(self, map):
self.map = map
def to_python(self, value):
return value
def to_url(self, value):
return url_quote(value, self.map.charset)
class UnicodeConverter(BaseConverter):
"""This converter is the default converter and accepts any string but
only one path segment. Thus the string can not include a slash.
This is the default validator.
Example::
Rule('/pages/<page>'),
Rule('/<string(length=2):lang_code>')
:param map: the :class:`Map`.
:param minlength: the minimum length of the string. Must be greater
or equal 1.
:param maxlength: the maximum length of the string.
:param length: the exact length of the string.
"""
def __init__(self, map, minlength=1, maxlength=None, length=None):
BaseConverter.__init__(self, map)
if length is not None:
length = '{%d}' % int(length)
else:
if maxlength is None:
maxlength = ''
else:
maxlength = int(maxlength)
length = '{%s,%s}' % (
int(minlength),
maxlength
)
self.regex = '[^/]' + length
class AnyConverter(BaseConverter):
"""Matches one of the items provided. Items can either be Python
identifiers or unicode strings::
Rule('/<any(about, help, imprint, u"class"):page_name>')
:param map: the :class:`Map`.
:param items: this function accepts the possible items as positional
arguments.
"""
def __init__(self, map, *items):
BaseConverter.__init__(self, map)
self.regex = '(?:%s)' % '|'.join([re.escape(x) for x in items])
class PathConverter(BaseConverter):
"""Like the default :class:`UnicodeConverter`, but it also matches
slashes. This is useful for wikis and similar applications::
Rule('/<path:wikipage>')
Rule('/<path:wikipage>/edit')
:param map: the :class:`Map`.
"""
regex = '[^/].*?'
is_greedy = True
weight = 50
class NumberConverter(BaseConverter):
"""Baseclass for `IntegerConverter` and `FloatConverter`.
:internal:
"""
def __init__(self, map, fixed_digits=0, min=None, max=None):
BaseConverter.__init__(self, map)
self.fixed_digits = fixed_digits
self.min = min
self.max = max
def to_python(self, value):
if (self.fixed_digits and len(value) != self.fixed_digits):
raise ValidationError()
value = self.num_convert(value)
if (self.min is not None and value < self.min) or \
(self.max is not None and value > self.max):
raise ValidationError()
return value
def to_url(self, value):
value = self.num_convert(value)
if self.fixed_digits:
value = ('%%0%sd' % self.fixed_digits) % value
return str(value)
class IntegerConverter(NumberConverter):
"""This converter only accepts integer values::
Rule('/page/<int:page>')
This converter does not support negative values.
:param map: the :class:`Map`.
:param fixed_digits: the number of fixed digits in the URL. If you set
this to ``4`` for example, the application will
only match if the url looks like ``/0001/``. The
default is variable length.
:param min: the minimal value.
:param max: the maximal value.
"""
regex = r'\d+'
num_convert = int
class FloatConverter(NumberConverter):
"""This converter only accepts floating point values::
Rule('/probability/<float:probability>')
This converter does not support negative values.
:param map: the :class:`Map`.
:param min: the minimal value.
:param max: the maximal value.
"""
regex = r'\d+\.\d+'
num_convert = float
def __init__(self, map, min=None, max=None):
NumberConverter.__init__(self, map, 0, min, max)
class Map(object):
"""The map class stores all the URL rules and some configuration
parameters. Some of the configuration values are only stored on the
`Map` instance since those affect all rules, others are just defaults
and can be overridden for each rule. Note that you have to specify all
arguments besides the `rules` as keyword arguments!
:param rules: sequence of url rules for this map.
:param default_subdomain: The default subdomain for rules without a
subdomain defined.
:param charset: charset of the url. defaults to ``"utf-8"``
:param strict_slashes: Take care of trailing slashes.
:param redirect_defaults: This will redirect to the default rule if it
wasn't visited that way. This helps creating
unique URLs.
:param converters: A dict of converters that adds additional converters
to the list of converters. If you redefine one
converter this will override the original one.
:param sort_parameters: If set to `True` the url parameters are sorted.
See `url_encode` for more details.
:param sort_key: The sort key function for `url_encode`.
.. versionadded:: 0.5
`sort_parameters` and `sort_key` was added.
"""
#: .. versionadded:: 0.6
#: a dict of default converters to be used.
default_converters = None
def __init__(self, rules=None, default_subdomain='', charset='utf-8',
strict_slashes=True, redirect_defaults=True,
converters=None, sort_parameters=False, sort_key=None):
self._rules = []
self._rules_by_endpoint = {}
self._remap = True
self.default_subdomain = default_subdomain
self.charset = charset
self.strict_slashes = strict_slashes
self.redirect_defaults = redirect_defaults
self.converters = self.default_converters.copy()
if converters:
self.converters.update(converters)
self.sort_parameters = sort_parameters
self.sort_key = sort_key
for rulefactory in rules or ():
self.add(rulefactory)
def is_endpoint_expecting(self, endpoint, *arguments):
"""Iterate over all rules and check if the endpoint expects
the arguments provided. This is for example useful if you have
some URLs that expect a language code and others that do not and
you want to wrap the builder a bit so that the current language
code is automatically added if not provided but endpoints expect
it.
:param endpoint: the endpoint to check.
:param arguments: this function accepts one or more arguments
as positional arguments. Each one of them is
checked.
"""
self.update()
arguments = set(arguments)
for rule in self._rules_by_endpoint[endpoint]:
if arguments.issubset(rule.arguments):
return True
return False
def iter_rules(self, endpoint=None):
"""Iterate over all rules or the rules of an endpoint.
:param endpoint: if provided only the rules for that endpoint
are returned.
:return: an iterator
"""
if endpoint is not None:
return iter(self._rules_by_endpoint[endpoint])
return iter(self._rules)
def add(self, rulefactory):
"""Add a new rule or factory to the map and bind it. Requires that the
rule is not bound to another map.
:param rulefactory: a :class:`Rule` or :class:`RuleFactory`
"""
for rule in rulefactory.get_rules(self):
rule.bind(self)
self._rules.append(rule)
self._rules_by_endpoint.setdefault(rule.endpoint, []).append(rule)
self._remap = True
def bind(self, server_name, script_name=None, subdomain=None,
url_scheme='http', default_method='GET', path_info=None):
"""Return a new :class:`MapAdapter` with the details specified to the
call. Note that `script_name` will default to ``'/'`` if not further
specified or `None`. The `server_name` at least is a requirement
because the HTTP RFC requires absolute URLs for redirects and so all
redirect exceptions raised by Werkzeug will contain the full canonical
URL.
If no path_info is passed to :meth:`match` it will use the default path
info passed to bind. While this doesn't really make sense for
manual bind calls, it's useful if you bind a map to a WSGI
environment which already contains the path info.
`subdomain` will default to the `default_subdomain` for this map if
no defined. If there is no `default_subdomain` you cannot use the
subdomain feature.
"""
if subdomain is None:
subdomain = self.default_subdomain
if script_name is None:
script_name = '/'
return MapAdapter(self, server_name, script_name, subdomain,
url_scheme, path_info, default_method)
def bind_to_environ(self, environ, server_name=None, subdomain=None):
"""Like :meth:`bind` but you can pass it an WSGI environment and it
will fetch the information from that dictionary. Note that because of
limitations in the protocol there is no way to get the current
subdomain and real `server_name` from the environment. If you don't
provide it, Werkzeug will use `SERVER_NAME` and `SERVER_PORT` (or
`HTTP_HOST` if provided) as used `server_name` with disabled subdomain
feature.
If `subdomain` is `None` but an environment and a server name is
provided it will calculate the current subdomain automatically.
Example: `server_name` is ``'example.com'`` and the `SERVER_NAME`
in the wsgi `environ` is ``'staging.dev.example.com'`` the calculated
subdomain will be ``'staging.dev'``.
If the object passed as environ has an environ attribute, the value of
this attribute is used instead. This allows you to pass request
objects. Additionally `PATH_INFO` added as a default of the
:class:`MapAdapter` so that you don't have to pass the path info to
the match method.
.. versionchanged:: 0.5
previously this method accepted a bogus `calculate_subdomain`
parameter that did not have any effect. It was removed because
of that.
:param environ: a WSGI environment.
:param server_name: an optional server name hint (see above).
:param subdomain: optionally the current subdomain (see above).
"""
environ = _get_environ(environ)
if server_name is None:
if 'HTTP_HOST' in environ:
server_name = environ['HTTP_HOST']
else:
server_name = environ['SERVER_NAME']
if (environ['wsgi.url_scheme'], environ['SERVER_PORT']) not \
in (('https', '443'), ('http', '80')):
server_name += ':' + environ['SERVER_PORT']
elif subdomain is None:
wsgi_server_name = environ.get('HTTP_HOST', environ['SERVER_NAME'])
cur_server_name = wsgi_server_name.split(':', 1)[0].split('.')
real_server_name = server_name.split(':', 1)[0].split('.')
offset = -len(real_server_name)
if cur_server_name[offset:] != real_server_name:
raise ValueError('the server name provided (%r) does not '
'match the server name from the WSGI '
'environment (%r)' %
(server_name, wsgi_server_name))
subdomain = '.'.join(filter(None, cur_server_name[:offset]))
return Map.bind(self, server_name, environ.get('SCRIPT_NAME'),
subdomain, environ['wsgi.url_scheme'],
environ['REQUEST_METHOD'], environ.get('PATH_INFO'))
def update(self):
"""Called before matching and building to keep the compiled rules
in the correct order after things changed.
"""
if self._remap:
self._rules.sort(lambda a, b: a.match_compare(b))
for rules in self._rules_by_endpoint.itervalues():
rules.sort(lambda a, b: a.build_compare(b))
self._remap = False
def __repr__(self):
rules = self.iter_rules()
return '%s([%s])' % (self.__class__.__name__, pformat(list(rules)))
class MapAdapter(object):
"""Returned by :meth:`Map.bind` or :meth:`Map.bind_to_environ` and does
the URL matching and building based on runtime information.
"""
def __init__(self, map, server_name, script_name, subdomain,
url_scheme, path_info, default_method):
self.map = map
self.server_name = server_name
if not script_name.endswith('/'):
script_name += '/'
self.script_name = script_name
self.subdomain = subdomain
self.url_scheme = url_scheme
self.path_info = path_info or u''
self.default_method = default_method
def dispatch(self, view_func, path_info=None, method=None,
catch_http_exceptions=False):
"""Does the complete dispatching process. `view_func` is called with
the endpoint and a dict with the values for the view. It should
look up the view function, call it, and return a response object
or WSGI application. http exceptions are not caught by default
so that applications can display nicer error messages by just
catching them by hand. If you want to stick with the default
error messages you can pass it ``catch_http_exceptions=True`` and
it will catch the http exceptions.
Here a small example for the dispatch usage::
from werkzeug import Request, Response, responder
from werkzeug.routing import Map, Rule
def on_index(request):
return Response('Hello from the index')
url_map = Map([Rule('/', endpoint='index')])
views = {'index': on_index}
@responder
def application(environ, start_response):
request = Request(environ)
urls = url_map.bind_to_environ(environ)
return urls.dispatch(lambda e, v: views[e](request, **v),
catch_http_exceptions=True)
Keep in mind that this method might return exception objects, too, so
use :class:`Response.force_type` to get a response object.
:param view_func: a function that is called with the endpoint as
first argument and the value dict as second. Has
to dispatch to the actual view function with this
information. (see above)
:param path_info: the path info to use for matching. Overrides the
path info specified on binding.
:param method: the HTTP method used for matching. Overrides the
method specified on binding.
:param catch_http_exceptions: set to `True` to catch any of the
werkzeug :class:`HTTPException`\s.
"""
try:
try:
endpoint, args = self.match(path_info, method)
except RequestRedirect, e:
return e
return view_func(endpoint, args)
except HTTPException, e:
if catch_http_exceptions:
return e
raise
def match(self, path_info=None, method=None, return_rule=False):
"""The usage is simple: you just pass the match method the current
path info as well as the method (which defaults to `GET`). The
following things can then happen:
- you receive a `NotFound` exception that indicates that no URL is
matching. A `NotFound` exception is also a WSGI application you
can call to get a default page not found page (happens to be the
same object as `werkzeug.exceptions.NotFound`)
- you receive a `MethodNotAllowed` exception that indicates that there
is a match for this URL but not for the current request method.
This is useful for RESTful applications.
- you receive a `RequestRedirect` exception with a `new_url`
attribute. This exception is used to notify you about a request
Werkzeug requests from your WSGI application. This is for example the
case if you request ``/foo`` although the correct URL is ``/foo/``
You can use the `RequestRedirect` instance as response-like object
similar to all other subclasses of `HTTPException`.
- you get a tuple in the form ``(endpoint, arguments)`` if there is
a match (unless `return_rule` is True, in which case you get a tuple
in the form ``(rule, arguments)``)
If the path info is not passed to the match method the default path
info of the map is used (defaults to the root URL if not defined
explicitly).
All of the exceptions raised are subclasses of `HTTPException` so they
can be used as WSGI responses. The will all render generic error or
redirect pages.
Here is a small example for matching:
>>> m = Map([
... Rule('/', endpoint='index'),
... Rule('/downloads/', endpoint='downloads/index'),
... Rule('/downloads/<int:id>', endpoint='downloads/show')
... ])
>>> urls = m.bind("example.com", "/")
>>> urls.match("/", "GET")
('index', {})
>>> urls.match("/downloads/42")
('downloads/show', {'id': 42})
And here is what happens on redirect and missing URLs:
>>> urls.match("/downloads")
Traceback (most recent call last):
...
RequestRedirect: http://example.com/downloads/
>>> urls.match("/missing")
Traceback (most recent call last):
...
NotFound: 404 Not Found
:param path_info: the path info to use for matching. Overrides the
path info specified on binding.
:param method: the HTTP method used for matching. Overrides the
method specified on binding.
:param return_rule: return the rule that matched instead of just the
endpoint (defaults to `False`).
.. versionadded:: 0.6
`return_rule` was added.
"""
self.map.update()
if path_info is None:
path_info = self.path_info
if not isinstance(path_info, unicode):
path_info = path_info.decode(self.map.charset, 'ignore')
method = (method or self.default_method).upper()
path = u'%s|/%s' % (self.subdomain, path_info.lstrip('/'))
have_match_for = set()
for rule in self.map._rules:
try:
rv = rule.match(path)
except RequestSlash:
raise RequestRedirect(str('%s://%s%s%s/%s/' % (
self.url_scheme,
self.subdomain and self.subdomain + '.' or '',
self.server_name,
self.script_name[:-1],
url_quote(path_info.lstrip('/'), self.map.charset)
)))
if rv is None:
continue
if rule.methods is not None and method not in rule.methods:
have_match_for.update(rule.methods)
continue
if self.map.redirect_defaults:
for r in self.map._rules_by_endpoint[rule.endpoint]:
if r.provides_defaults_for(rule) and \
r.suitable_for(rv, method):
rv.update(r.defaults)
subdomain, path = r.build(rv)
raise RequestRedirect(str('%s://%s%s%s/%s' % (
self.url_scheme,
subdomain and subdomain + '.' or '',
self.server_name,
self.script_name[:-1],
url_quote(path.lstrip('/'), self.map.charset)
)))
if rule.redirect_to is not None:
if isinstance(rule.redirect_to, basestring):
def _handle_match(match):
value = rv[match.group(1)]
return rule._converters[match.group(1)].to_url(value)
redirect_url = _simple_rule_re.sub(_handle_match,
rule.redirect_to)
else:
redirect_url = rule.redirect_to(self, **rv)
raise RequestRedirect(str(urljoin('%s://%s%s%s' % (
self.url_scheme,
self.subdomain and self.subdomain + '.' or '',
self.server_name,
self.script_name
), redirect_url)))
if return_rule:
return rule, rv
else:
return rule.endpoint, rv
if have_match_for:
raise MethodNotAllowed(valid_methods=list(have_match_for))
raise NotFound()
def test(self, path_info=None, method=None):
"""Test if a rule would match. Works like `match` but returns `True`
if the URL matches, or `False` if it does not exist.
:param path_info: the path info to use for matching. Overrides the
path info specified on binding.
:param method: the HTTP method used for matching. Overrides the
method specified on binding.
"""
try:
self.match(path_info, method)
except RequestRedirect:
pass
except NotFound:
return False
return True
def _partial_build(self, endpoint, values, method, append_unknown):
"""Helper for :meth:`build`. Returns subdomain and path for the
rule that accepts this endpoint, values and method.
:internal:
"""
# in case the method is none, try with the default method first
if method is None:
rv = self._partial_build(endpoint, values, self.default_method,
append_unknown)
if rv is not None:
return rv
# default method did not match or a specific method is passed,
# check all and go with first result.
for rule in self.map._rules_by_endpoint.get(endpoint, ()):
if rule.suitable_for(values, method):
rv = rule.build(values, append_unknown)
if rv is not None:
return rv
def build(self, endpoint, values=None, method=None, force_external=False,
append_unknown=True):
"""Building URLs works pretty much the other way round. Instead of
`match` you call `build` and pass it the endpoint and a dict of
arguments for the placeholders.
The `build` function also accepts an argument called `force_external`
which, if you set it to `True` will force external URLs. Per default
external URLs (include the server name) will only be used if the
target URL is on a different subdomain.
>>> m = Map([
... Rule('/', endpoint='index'),
... Rule('/downloads/', endpoint='downloads/index'),
... Rule('/downloads/<int:id>', endpoint='downloads/show')
... ])
>>> urls = m.bind("example.com", "/")
>>> urls.build("index", {})
'/'
>>> urls.build("downloads/show", {'id': 42})
'/downloads/42'
>>> urls.build("downloads/show", {'id': 42}, force_external=True)
'http://example.com/downloads/42'
Because URLs cannot contain non ASCII data you will always get
bytestrings back. Non ASCII characters are urlencoded with the
charset defined on the map instance.
Additional values are converted to unicode and appended to the URL as
URL querystring parameters:
>>> urls.build("index", {'q': 'My Searchstring'})
'/?q=My+Searchstring'
If a rule does not exist when building a `BuildError` exception is
raised.
The build method accepts an argument called `method` which allows you
to specify the method you want to have an URL built for if you have
different methods for the same endpoint specified.
.. versionadded:: 0.6
the `append_unknown` parameter was added.
:param endpoint: the endpoint of the URL to build.
:param values: the values for the URL to build. Unhandled values are
appended to the URL as query parameters.
:param method: the HTTP method for the rule if there are different
URLs for different methods on the same endpoint.
:param force_external: enforce full canonical external URLs.
:param append_unknown: unknown parameters are appended to the generated
URL as query string argument. Disable this
if you want the builder to ignore those.
"""
self.map.update()
if values:
if isinstance(values, MultiDict):
values = dict((k, v) for k, v in values.iteritems(multi=True)
if v is not None)
else:
values = dict((k, v) for k, v in values.iteritems()
if v is not None)
else:
values = {}
rv = self._partial_build(endpoint, values, method, append_unknown)
if rv is None:
raise BuildError(endpoint, values, method)
subdomain, path = rv
if not force_external and subdomain == self.subdomain:
return str(urljoin(self.script_name, path.lstrip('/')))
return str('%s://%s%s%s/%s' % (
self.url_scheme,
subdomain and subdomain + '.' or '',
self.server_name,
self.script_name[:-1],
path.lstrip('/')
))
#: the default converter mapping for the map.
DEFAULT_CONVERTERS = {
'default': UnicodeConverter,
'string': UnicodeConverter,
'any': AnyConverter,
'path': PathConverter,
'int': IntegerConverter,
'float': FloatConverter
}
from werkzeug.datastructures import ImmutableDict, MultiDict
Map.default_converters = ImmutableDict(DEFAULT_CONVERTERS)
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment