Merge flask framework and other stuff from master

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diff --git a/python/werkzeug/routing.py b/python/werkzeug/routing.py
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+# -*- 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`
+    exception is raised.
+
+
+    :copyright: 2007 Pallets
+    :license: BSD-3-Clause
+"""
+import ast
+import difflib
+import posixpath
+import re
+import uuid
+from pprint import pformat
+from threading import Lock
+
+from ._compat import implements_to_string
+from ._compat import iteritems
+from ._compat import itervalues
+from ._compat import native_string_result
+from ._compat import string_types
+from ._compat import text_type
+from ._compat import to_bytes
+from ._compat import to_unicode
+from ._compat import wsgi_decoding_dance
+from ._internal import _encode_idna
+from ._internal import _get_environ
+from .datastructures import ImmutableDict
+from .datastructures import MultiDict
+from .exceptions import BadHost
+from .exceptions import HTTPException
+from .exceptions import MethodNotAllowed
+from .exceptions import NotFound
+from .urls import _fast_url_quote
+from .urls import url_encode
+from .urls import url_join
+from .urls import url_quote
+from .utils import cached_property
+from .utils import format_string
+from .utils import redirect
+from .wsgi import get_host
+
+_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"<([^>]+)>")
+_converter_args_re = re.compile(
+    r"""
+    ((?P<name>\w+)\s*=\s*)?
+    (?P<value>
+        True|False|
+        \d+.\d+|
+        \d+.|
+        \d+|
+        [\w\d_.]+|
+        [urUR]?(?P<stringval>"[^"]*?"|'[^']*')
+    )\s*,
+    """,
+    re.VERBOSE | re.UNICODE,
+)
+
+
+_PYTHON_CONSTANTS = {"None": None, "True": True, "False": False}
+
+
+def _pythonize(value):
+    if value in _PYTHON_CONSTANTS:
+        return _PYTHON_CONSTANTS[value]
+    for convert in int, float:
+        try:
+            return convert(value)
+        except ValueError:
+            pass
+    if value[:1] == value[-1:] and value[0] in "\"'":
+        value = value[1:-1]
+    return text_type(value)
+
+
+def parse_converter_args(argstr):
+    argstr += ","
+    args = []
+    kwargs = {}
+
+    for item in _converter_args_re.finditer(argstr):
+        value = item.group("stringval")
+        if value is None:
+            value = item.group("value")
+        value = _pythonize(value)
+        if not item.group("name"):
+            args.append(value)
+        else:
+            name = item.group("name")
+            kwargs[name] = value
+
+    return tuple(args), kwargs
+
+
+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
+
+
+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 = 308
+
+    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, self.code)
+
+
+class RequestSlash(RoutingException):
+    """Internal exception."""
+
+
+class RequestAliasRedirect(RoutingException):  # noqa: B903
+    """This rule is an alias and wants to redirect to the canonical URL."""
+
+    def __init__(self, matched_values):
+        self.matched_values = matched_values
+
+
+@implements_to_string
+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, adapter=None):
+        LookupError.__init__(self, endpoint, values, method)
+        self.endpoint = endpoint
+        self.values = values
+        self.method = method
+        self.adapter = adapter
+
+    @cached_property
+    def suggested(self):
+        return self.closest_rule(self.adapter)
+
+    def closest_rule(self, adapter):
+        def _score_rule(rule):
+            return sum(
+                [
+                    0.98
+                    * difflib.SequenceMatcher(
+                        None, rule.endpoint, self.endpoint
+                    ).ratio(),
+                    0.01 * bool(set(self.values or ()).issubset(rule.arguments)),
+                    0.01 * bool(rule.methods and self.method in rule.methods),
+                ]
+            )
+
+        if adapter and adapter.map._rules:
+            return max(adapter.map._rules, key=_score_rule)
+
+    def __str__(self):
+        message = []
+        message.append("Could not build url for endpoint %r" % self.endpoint)
+        if self.method:
+            message.append(" (%r)" % self.method)
+        if self.values:
+            message.append(" with values %r" % sorted(self.values.keys()))
+        message.append(".")
+        if self.suggested:
+            if self.endpoint == self.suggested.endpoint:
+                if self.method and self.method not in self.suggested.methods:
+                    message.append(
+                        " Did you mean to use methods %r?"
+                        % sorted(self.suggested.methods)
+                    )
+                missing_values = self.suggested.arguments.union(
+                    set(self.suggested.defaults or ())
+                ) - set(self.values.keys())
+                if missing_values:
+                    message.append(
+                        " Did you forget to specify values %r?" % sorted(missing_values)
+                    )
+            else:
+                message.append(" Did you mean %r instead?" % self.suggested.endpoint)
+        return u"".join(message)
+
+
+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:
+                    new_defaults = {}
+                    for key, value in iteritems(rule.defaults):
+                        if isinstance(value, string_types):
+                            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, string_types):
+                    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,
+                )
+
+
+def _prefix_names(src):
+    """ast parse and prefix names with `.` to avoid collision with user vars"""
+    tree = ast.parse(src).body[0]
+    if isinstance(tree, ast.Expr):
+        tree = tree.value
+    for node in ast.walk(tree):
+        if isinstance(node, ast.Name):
+            node.id = "." + node.id
+    return tree
+
+
+_CALL_CONVERTER_CODE_FMT = "self._converters[{elem!r}].to_url()"
+_IF_KWARGS_URL_ENCODE_CODE = """\
+if kwargs:
+    q = '?'
+    params = self._encode_query_vars(kwargs)
+else:
+    q = params = ''
+"""
+_IF_KWARGS_URL_ENCODE_AST = _prefix_names(_IF_KWARGS_URL_ENCODE_CODE)
+_URL_ENCODE_AST_NAMES = (_prefix_names("q"), _prefix_names("params"))
+
+
+@implements_to_string
+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.
+
+    `alias`
+        If enabled this rule serves as an alias for another rule with the same
+        endpoint and arguments.
+
+    `host`
+        If provided and the URL map has host matching enabled this can be
+        used to provide a match rule for the whole host.  This also means
+        that the subdomain feature is disabled.
+
+    .. versionadded:: 0.7
+       The `alias` and `host` parameters were added.
+    """
+
+    def __init__(
+        self,
+        string,
+        defaults=None,
+        subdomain=None,
+        methods=None,
+        build_only=False,
+        endpoint=None,
+        strict_slashes=None,
+        redirect_to=None,
+        alias=False,
+        host=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.host = host
+        self.defaults = defaults
+        self.build_only = build_only
+        self.alias = alias
+        if methods is None:
+            self.methods = None
+        else:
+            if isinstance(methods, str):
+                raise TypeError("param `methods` should be `Iterable[str]`, not `str`")
+            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.redirect_to = redirect_to
+
+        if defaults:
+            self.arguments = set(map(str, defaults))
+        else:
+            self.arguments = set()
+        self._trace = self._converters = self._regex = self._argument_weights = None
+
+    def empty(self):
+        """
+        Return an unbound copy of this rule.
+
+        This can be useful if want to reuse an already bound URL for another
+        map.  See ``get_empty_kwargs`` to override what keyword arguments are
+        provided to the new copy.
+        """
+        return type(self)(self.rule, **self.get_empty_kwargs())
+
+    def get_empty_kwargs(self):
+        """
+        Provides kwargs for instantiating empty copy with empty()
+
+        Use this method to provide custom keyword arguments to the subclass of
+        ``Rule`` when calling ``some_rule.empty()``.  Helpful when the subclass
+        has custom keyword arguments that are needed at instantiation.
+
+        Must return a ``dict`` that will be provided as kwargs to the new
+        instance of ``Rule``, following the initial ``self.rule`` value which
+        is always provided as the first, required positional argument.
+        """
+        defaults = None
+        if self.defaults:
+            defaults = dict(self.defaults)
+        return dict(
+            defaults=defaults,
+            subdomain=self.subdomain,
+            methods=self.methods,
+            build_only=self.build_only,
+            endpoint=self.endpoint,
+            strict_slashes=self.strict_slashes,
+            redirect_to=self.redirect_to,
+            alias=self.alias,
+            host=self.host,
+        )
+
+    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
+        self.compile()
+
+    def get_converter(self, variable_name, converter_name, args, kwargs):
+        """Looks up the converter for the given parameter.
+
+        .. versionadded:: 0.9
+        """
+        if converter_name not in self.map.converters:
+            raise LookupError("the converter %r does not exist" % converter_name)
+        return self.map.converters[converter_name](self.map, *args, **kwargs)
+
+    def _encode_query_vars(self, query_vars):
+        return url_encode(
+            query_vars,
+            charset=self.map.charset,
+            sort=self.map.sort_parameters,
+            key=self.map.sort_key,
+        )
+
+    def compile(self):
+        """Compiles the regular expression and stores it."""
+        assert self.map is not None, "rule not bound"
+
+        if self.map.host_matching:
+            domain_rule = self.host or ""
+        else:
+            domain_rule = self.subdomain or ""
+
+        self._trace = []
+        self._converters = {}
+        self._static_weights = []
+        self._argument_weights = []
+        regex_parts = []
+
+        def _build_regex(rule):
+            index = 0
+            for converter, arguments, variable in parse_rule(rule):
+                if converter is None:
+                    regex_parts.append(re.escape(variable))
+                    self._trace.append((False, variable))
+                    for part in variable.split("/"):
+                        if part:
+                            self._static_weights.append((index, -len(part)))
+                else:
+                    if arguments:
+                        c_args, c_kwargs = parse_converter_args(arguments)
+                    else:
+                        c_args = ()
+                        c_kwargs = {}
+                    convobj = self.get_converter(variable, converter, c_args, c_kwargs)
+                    regex_parts.append("(?P<%s>%s)" % (variable, convobj.regex))
+                    self._converters[variable] = convobj
+                    self._trace.append((True, variable))
+                    self._argument_weights.append(convobj.weight)
+                    self.arguments.add(str(variable))
+                index = index + 1
+
+        _build_regex(domain_rule)
+        regex_parts.append("\\|")
+        self._trace.append((False, "|"))
+        _build_regex(self.rule if self.is_leaf else self.rule.rstrip("/"))
+        if not self.is_leaf:
+            self._trace.append((False, "/"))
+
+        self._build = self._compile_builder(False).__get__(self, None)
+        self._build_unknown = self._compile_builder(True).__get__(self, None)
+
+        if self.build_only:
+            return
+        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, method=None):
+        """Check if the rule matches a given path. Path is a string in the
+        form ``"subdomain|/path"`` and is assembled by the map.  If
+        the map is doing host matching the subdomain part will be the host
+        instead.
+
+        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__")
+                    and (
+                        method is None or self.methods is None or method in self.methods
+                    )
+                ):
+                    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 iteritems(groups):
+                    try:
+                        value = self._converters[name].to_python(value)
+                    except ValidationError:
+                        return
+                    result[str(name)] = value
+                if self.defaults:
+                    result.update(self.defaults)
+
+                if self.alias and self.map.redirect_defaults:
+                    raise RequestAliasRedirect(result)
+
+                return result
+
+    @staticmethod
+    def _get_func_code(code, name):
+        globs, locs = {}, {}
+        exec(code, globs, locs)
+        return locs[name]
+
+    def _compile_builder(self, append_unknown=True):
+        defaults = self.defaults or {}
+        dom_ops = []
+        url_ops = []
+
+        opl = dom_ops
+        for is_dynamic, data in self._trace:
+            if data == "|" and opl is dom_ops:
+                opl = url_ops
+                continue
+            # this seems like a silly case to ever come up but:
+            # if a default is given for a value that appears in the rule,
+            # resolve it to a constant ahead of time
+            if is_dynamic and data in defaults:
+                data = self._converters[data].to_url(defaults[data])
+                opl.append((False, data))
+            elif not is_dynamic:
+                opl.append(
+                    (False, url_quote(to_bytes(data, self.map.charset), safe="/:|+"))
+                )
+            else:
+                opl.append((True, data))
+
+        def _convert(elem):
+            ret = _prefix_names(_CALL_CONVERTER_CODE_FMT.format(elem=elem))
+            ret.args = [ast.Name(str(elem), ast.Load())]  # str for py2
+            return ret
+
+        def _parts(ops):
+            parts = [
+                _convert(elem) if is_dynamic else ast.Str(s=elem)
+                for is_dynamic, elem in ops
+            ]
+            parts = parts or [ast.Str("")]
+            # constant fold
+            ret = [parts[0]]
+            for p in parts[1:]:
+                if isinstance(p, ast.Str) and isinstance(ret[-1], ast.Str):
+                    ret[-1] = ast.Str(ret[-1].s + p.s)
+                else:
+                    ret.append(p)
+            return ret
+
+        dom_parts = _parts(dom_ops)
+        url_parts = _parts(url_ops)
+        if not append_unknown:
+            body = []
+        else:
+            body = [_IF_KWARGS_URL_ENCODE_AST]
+            url_parts.extend(_URL_ENCODE_AST_NAMES)
+
+        def _join(parts):
+            if len(parts) == 1:  # shortcut
+                return parts[0]
+            elif hasattr(ast, "JoinedStr"):  # py36+
+                return ast.JoinedStr(parts)
+            else:
+                call = _prefix_names('"".join()')
+                call.args = [ast.Tuple(parts, ast.Load())]
+                return call
+
+        body.append(
+            ast.Return(ast.Tuple([_join(dom_parts), _join(url_parts)], ast.Load()))
+        )
+
+        # str is necessary for python2
+        pargs = [
+            str(elem)
+            for is_dynamic, elem in dom_ops + url_ops
+            if is_dynamic and elem not in defaults
+        ]
+        kargs = [str(k) for k in defaults]
+
+        func_ast = _prefix_names("def _(): pass")
+        func_ast.name = "<builder:{!r}>".format(self.rule)
+        if hasattr(ast, "arg"):  # py3
+            func_ast.args.args.append(ast.arg(".self", None))
+            for arg in pargs + kargs:
+                func_ast.args.args.append(ast.arg(arg, None))
+            func_ast.args.kwarg = ast.arg(".kwargs", None)
+        else:
+            func_ast.args.args.append(ast.Name(".self", ast.Load()))
+            for arg in pargs + kargs:
+                func_ast.args.args.append(ast.Name(arg, ast.Load()))
+            func_ast.args.kwarg = ".kwargs"
+        for _ in kargs:
+            func_ast.args.defaults.append(ast.Str(""))
+        func_ast.body = body
+
+        module = ast.fix_missing_locations(ast.Module([func_ast]))
+        code = compile(module, "<werkzeug routing>", "exec")
+        return self._get_func_code(code, func_ast.name)
+
+    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:
+        """
+        try:
+            if append_unknown:
+                return self._build_unknown(**values)
+            else:
+                return self._build(**values)
+        except ValidationError:
+            return None
+
+    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
+            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 a method was given explicitly and that method is not supported
+        # by this rule, this rule is not suitable.
+        if (
+            method is not None
+            and self.methods is not None
+            and method not in self.methods
+        ):
+            return False
+
+        defaults = self.defaults or ()
+
+        # all arguments required must be either in the defaults dict or
+        # the value dictionary otherwise it's not suitable
+        for key in self.arguments:
+            if key not in defaults and key not in values:
+                return False
+
+        # in case defaults are given we ensure that either the value was
+        # skipped or the value is the same as the default value.
+        if defaults:
+            for key, value in iteritems(defaults):
+                if key in values and value != values[key]:
+                    return False
+
+        return True
+
+    def match_compare_key(self):
+        """The match compare key for sorting.
+
+        Current implementation:
+
+        1.  rules without any arguments come first for performance
+            reasons only as we expect them to match faster and some
+            common ones usually don't have any arguments (index pages etc.)
+        2.  rules with more static parts come first so the second argument
+            is the negative length of the number of the static weights.
+        3.  we order by static weights, which is a combination of index
+            and length
+        4.  The more complex rules come first so the next argument is the
+            negative length of the number of argument weights.
+        5.  lastly we order by the actual argument weights.
+
+        :internal:
+        """
+        return (
+            bool(self.arguments),
+            -len(self._static_weights),
+            self._static_weights,
+            -len(self._argument_weights),
+            self._argument_weights,
+        )
+
+    def build_compare_key(self):
+        """The build compare key for sorting.
+
+        :internal:
+        """
+        return 1 if self.alias else 0, -len(self.arguments), -len(self.defaults or ())
+
+    def __eq__(self, other):
+        return self.__class__ is other.__class__ and self._trace == other._trace
+
+    __hash__ = None
+
+    def __ne__(self, other):
+        return not self.__eq__(other)
+
+    def __str__(self):
+        return self.rule
+
+    @native_string_result
+    def __repr__(self):
+        if self.map is None:
+            return u"<%s (unbound)>" % self.__class__.__name__
+        tmp = []
+        for is_dynamic, data in self._trace:
+            if is_dynamic:
+                tmp.append(u"<%s>" % data)
+            else:
+                tmp.append(data)
+        return u"<%s %s%s -> %s>" % (
+            self.__class__.__name__,
+            repr((u"".join(tmp)).lstrip(u"|")).lstrip(u"u"),
+            self.methods is not None and u" (%s)" % u", ".join(self.methods) or u"",
+            self.endpoint,
+        )
+
+
+class BaseConverter(object):
+    """Base class for all converters."""
+
+    regex = "[^/]+"
+    weight = 100
+
+    def __init__(self, map):
+        self.map = map
+
+    def to_python(self, value):
+        return value
+
+    def to_url(self, value):
+        if isinstance(value, (bytes, bytearray)):
+            return _fast_url_quote(value)
+        return _fast_url_quote(text_type(value).encode(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 strings::
+
+        Rule('/<any(about, help, imprint, class, "foo,bar"):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 = "[^/].*?"
+    weight = 200
+
+
+class NumberConverter(BaseConverter):
+    """Baseclass for `IntegerConverter` and `FloatConverter`.
+
+    :internal:
+    """
+
+    weight = 50
+
+    def __init__(self, map, fixed_digits=0, min=None, max=None, signed=False):
+        if signed:
+            self.regex = self.signed_regex
+        BaseConverter.__init__(self, map)
+        self.fixed_digits = fixed_digits
+        self.min = min
+        self.max = max
+        self.signed = signed
+
+    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)
+
+    @property
+    def signed_regex(self):
+        return r"-?" + self.regex
+
+
+class IntegerConverter(NumberConverter):
+    """This converter only accepts integer values::
+
+        Rule("/page/<int:page>")
+
+    By default it only accepts unsigned, positive values. The ``signed``
+    parameter will enable signed, negative values. ::
+
+        Rule("/page/<int(signed=True):page>")
+
+    :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 rule will only match if the
+        URL looks like ``/0001/``. The default is variable length.
+    :param min: The minimal value.
+    :param max: The maximal value.
+    :param signed: Allow signed (negative) values.
+
+    .. versionadded:: 0.15
+        The ``signed`` parameter.
+    """
+
+    regex = r"\d+"
+    num_convert = int
+
+
+class FloatConverter(NumberConverter):
+    """This converter only accepts floating point values::
+
+        Rule("/probability/<float:probability>")
+
+    By default it only accepts unsigned, positive values. The ``signed``
+    parameter will enable signed, negative values. ::
+
+        Rule("/offset/<float(signed=True):offset>")
+
+    :param map: The :class:`Map`.
+    :param min: The minimal value.
+    :param max: The maximal value.
+    :param signed: Allow signed (negative) values.
+
+    .. versionadded:: 0.15
+        The ``signed`` parameter.
+    """
+
+    regex = r"\d+\.\d+"
+    num_convert = float
+
+    def __init__(self, map, min=None, max=None, signed=False):
+        NumberConverter.__init__(self, map, min=min, max=max, signed=signed)
+
+
+class UUIDConverter(BaseConverter):
+    """This converter only accepts UUID strings::
+
+        Rule('/object/<uuid:identifier>')
+
+    .. versionadded:: 0.10
+
+    :param map: the :class:`Map`.
+    """
+
+    regex = (
+        r"[A-Fa-f0-9]{8}-[A-Fa-f0-9]{4}-"
+        r"[A-Fa-f0-9]{4}-[A-Fa-f0-9]{4}-[A-Fa-f0-9]{12}"
+    )
+
+    def to_python(self, value):
+        return uuid.UUID(value)
+
+    def to_url(self, value):
+        return str(value)
+
+
+#: the default converter mapping for the map.
+DEFAULT_CONVERTERS = {
+    "default": UnicodeConverter,
+    "string": UnicodeConverter,
+    "any": AnyConverter,
+    "path": PathConverter,
+    "int": IntegerConverter,
+    "float": FloatConverter,
+    "uuid": UUIDConverter,
+}
+
+
+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`.
+    :param encoding_errors: the error method to use for decoding
+    :param host_matching: if set to `True` it enables the host matching
+                          feature and disables the subdomain one.  If
+                          enabled the `host` parameter to rules is used
+                          instead of the `subdomain` one.
+
+    .. versionadded:: 0.5
+        `sort_parameters` and `sort_key` was added.
+
+    .. versionadded:: 0.7
+        `encoding_errors` and `host_matching` was added.
+    """
+
+    #: A dict of default converters to be used.
+    default_converters = ImmutableDict(DEFAULT_CONVERTERS)
+
+    def __init__(
+        self,
+        rules=None,
+        default_subdomain="",
+        charset="utf-8",
+        strict_slashes=True,
+        redirect_defaults=True,
+        converters=None,
+        sort_parameters=False,
+        sort_key=None,
+        encoding_errors="replace",
+        host_matching=False,
+    ):
+        self._rules = []
+        self._rules_by_endpoint = {}
+        self._remap = True
+        self._remap_lock = Lock()
+
+        self.default_subdomain = default_subdomain
+        self.charset = charset
+        self.encoding_errors = encoding_errors
+        self.strict_slashes = strict_slashes
+        self.redirect_defaults = redirect_defaults
+        self.host_matching = host_matching
+
+        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
+        """
+        self.update()
+        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,
+        query_args=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.
+
+        .. versionadded:: 0.7
+           `query_args` added
+
+        .. versionadded:: 0.8
+           `query_args` can now also be a string.
+
+        .. versionchanged:: 0.15
+            ``path_info`` defaults to ``'/'`` if ``None``.
+        """
+        server_name = server_name.lower()
+        if self.host_matching:
+            if subdomain is not None:
+                raise RuntimeError("host matching enabled and a subdomain was provided")
+        elif subdomain is None:
+            subdomain = self.default_subdomain
+        if script_name is None:
+            script_name = "/"
+        if path_info is None:
+            path_info = "/"
+        try:
+            server_name = _encode_idna(server_name)
+        except UnicodeError:
+            raise BadHost()
+        return MapAdapter(
+            self,
+            server_name,
+            script_name,
+            subdomain,
+            url_scheme,
+            path_info,
+            default_method,
+            query_args,
+        )
+
+    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.
+
+        .. versionchanged:: 0.8
+           This will no longer raise a ValueError when an unexpected server
+           name was passed.
+
+        :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)
+
+        wsgi_server_name = get_host(environ).lower()
+
+        if server_name is None:
+            server_name = wsgi_server_name
+        else:
+            server_name = server_name.lower()
+
+        if subdomain is None and not self.host_matching:
+            cur_server_name = wsgi_server_name.split(".")
+            real_server_name = server_name.split(".")
+            offset = -len(real_server_name)
+            if cur_server_name[offset:] != real_server_name:
+                # This can happen even with valid configs if the server was
+                # accesssed directly by IP address under some situations.
+                # Instead of raising an exception like in Werkzeug 0.7 or
+                # earlier we go by an invalid subdomain which will result
+                # in a 404 error on matching.
+                subdomain = "<invalid>"
+            else:
+                subdomain = ".".join(filter(None, cur_server_name[:offset]))
+
+        def _get_wsgi_string(name):
+            val = environ.get(name)
+            if val is not None:
+                return wsgi_decoding_dance(val, self.charset)
+
+        script_name = _get_wsgi_string("SCRIPT_NAME")
+        path_info = _get_wsgi_string("PATH_INFO")
+        query_args = _get_wsgi_string("QUERY_STRING")
+        return Map.bind(
+            self,
+            server_name,
+            script_name,
+            subdomain,
+            environ["wsgi.url_scheme"],
+            environ["REQUEST_METHOD"],
+            path_info,
+            query_args=query_args,
+        )
+
+    def update(self):
+        """Called before matching and building to keep the compiled rules
+        in the correct order after things changed.
+        """
+        if not self._remap:
+            return
+
+        with self._remap_lock:
+            if not self._remap:
+                return
+
+            self._rules.sort(key=lambda x: x.match_compare_key())
+            for rules in itervalues(self._rules_by_endpoint):
+                rules.sort(key=lambda x: x.build_compare_key())
+            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,
+        query_args=None,
+    ):
+        self.map = map
+        self.server_name = to_unicode(server_name)
+        script_name = to_unicode(script_name)
+        if not script_name.endswith(u"/"):
+            script_name += u"/"
+        self.script_name = script_name
+        self.subdomain = to_unicode(subdomain)
+        self.url_scheme = to_unicode(url_scheme)
+        self.path_info = to_unicode(path_info)
+        self.default_method = to_unicode(default_method)
+        self.query_args = query_args
+
+    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.wrappers import Request, Response
+            from werkzeug.wsgi import 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 as e:
+                return e
+            return view_func(endpoint, args)
+        except HTTPException as e:
+            if catch_http_exceptions:
+                return e
+            raise
+
+    def match(self, path_info=None, method=None, return_rule=False, query_args=None):
+        """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. They 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`).
+        :param query_args: optional query arguments that are used for
+                           automatic redirects as string or dictionary.  It's
+                           currently not possible to use the query arguments
+                           for URL matching.
+
+        .. versionadded:: 0.6
+           `return_rule` was added.
+
+        .. versionadded:: 0.7
+           `query_args` was added.
+
+        .. versionchanged:: 0.8
+           `query_args` can now also be a string.
+        """
+        self.map.update()
+        if path_info is None:
+            path_info = self.path_info
+        else:
+            path_info = to_unicode(path_info, self.map.charset)
+        if query_args is None:
+            query_args = self.query_args
+        method = (method or self.default_method).upper()
+
+        path = u"%s|%s" % (
+            self.map.host_matching and self.server_name or self.subdomain,
+            path_info and "/%s" % path_info.lstrip("/"),
+        )
+
+        have_match_for = set()
+        for rule in self.map._rules:
+            try:
+                rv = rule.match(path, method)
+            except RequestSlash:
+                raise RequestRedirect(
+                    self.make_redirect_url(
+                        url_quote(path_info, self.map.charset, safe="/:|+") + "/",
+                        query_args,
+                    )
+                )
+            except RequestAliasRedirect as e:
+                raise RequestRedirect(
+                    self.make_alias_redirect_url(
+                        path, rule.endpoint, e.matched_values, method, query_args
+                    )
+                )
+            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:
+                redirect_url = self.get_default_redirect(rule, method, rv, query_args)
+                if redirect_url is not None:
+                    raise RequestRedirect(redirect_url)
+
+            if rule.redirect_to is not None:
+                if isinstance(rule.redirect_to, string_types):
+
+                    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(
+                        url_join(
+                            "%s://%s%s%s"
+                            % (
+                                self.url_scheme or "http",
+                                self.subdomain + "." if self.subdomain else "",
+                                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 HTTPException:
+            return False
+        return True
+
+    def allowed_methods(self, path_info=None):
+        """Returns the valid methods that match for a given path.
+
+        .. versionadded:: 0.7
+        """
+        try:
+            self.match(path_info, method="--")
+        except MethodNotAllowed as e:
+            return e.valid_methods
+        except HTTPException:
+            pass
+        return []
+
+    def get_host(self, domain_part):
+        """Figures out the full host name for the given domain part.  The
+        domain part is a subdomain in case host matching is disabled or
+        a full host name.
+        """
+        if self.map.host_matching:
+            if domain_part is None:
+                return self.server_name
+            return to_unicode(domain_part, "ascii")
+        subdomain = domain_part
+        if subdomain is None:
+            subdomain = self.subdomain
+        else:
+            subdomain = to_unicode(subdomain, "ascii")
+        return (subdomain + u"." if subdomain else u"") + self.server_name
+
+    def get_default_redirect(self, rule, method, values, query_args):
+        """A helper that returns the URL to redirect to if it finds one.
+        This is used for default redirecting only.
+
+        :internal:
+        """
+        assert self.map.redirect_defaults
+        for r in self.map._rules_by_endpoint[rule.endpoint]:
+            # every rule that comes after this one, including ourself
+            # has a lower priority for the defaults.  We order the ones
+            # with the highest priority up for building.
+            if r is rule:
+                break
+            if r.provides_defaults_for(rule) and r.suitable_for(values, method):
+                values.update(r.defaults)
+                domain_part, path = r.build(values)
+                return self.make_redirect_url(path, query_args, domain_part=domain_part)
+
+    def encode_query_args(self, query_args):
+        if not isinstance(query_args, string_types):
+            query_args = url_encode(query_args, self.map.charset)
+        return query_args
+
+    def make_redirect_url(self, path_info, query_args=None, domain_part=None):
+        """Creates a redirect URL.
+
+        :internal:
+        """
+        suffix = ""
+        if query_args:
+            suffix = "?" + self.encode_query_args(query_args)
+        return str(
+            "%s://%s/%s%s"
+            % (
+                self.url_scheme or "http",
+                self.get_host(domain_part),
+                posixpath.join(
+                    self.script_name[:-1].lstrip("/"), path_info.lstrip("/")
+                ),
+                suffix,
+            )
+        )
+
+    def make_alias_redirect_url(self, path, endpoint, values, method, query_args):
+        """Internally called to make an alias redirect URL."""
+        url = self.build(
+            endpoint, values, method, append_unknown=False, force_external=True
+        )
+        if query_args:
+            url += "?" + self.encode_query_args(query_args)
+        assert url != path, "detected invalid alias setting. No canonical URL found"
+        return url
+
+    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'
+
+        When processing those additional values, lists are furthermore
+        interpreted as multiple values (as per
+        :py:class:`werkzeug.datastructures.MultiDict`):
+
+        >>> urls.build("index", {'q': ['a', 'b', 'c']})
+        '/?q=a&q=b&q=c'
+
+        Passing a ``MultiDict`` will also add multiple values:
+
+        >>> urls.build("index", MultiDict((('p', 'z'), ('q', 'a'), ('q', 'b'))))
+        '/?p=z&q=a&q=b'
+
+        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. If the URL
+                               scheme is not provided, this will generate
+                               a protocol-relative URL.
+        :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):
+                temp_values = {}
+                # iteritems(dict, values) is like `values.lists()`
+                # without the call or `list()` coercion overhead.
+                for key, value in iteritems(dict, values):
+                    if not value:
+                        continue
+                    if len(value) == 1:  # flatten single item lists
+                        value = value[0]
+                        if value is None:  # drop None
+                            continue
+                    temp_values[key] = value
+                values = temp_values
+            else:
+                # drop None
+                values = dict(i for i in iteritems(values) if i[1] is not None)
+        else:
+            values = {}
+
+        rv = self._partial_build(endpoint, values, method, append_unknown)
+        if rv is None:
+            raise BuildError(endpoint, values, method, self)
+        domain_part, path = rv
+
+        host = self.get_host(domain_part)
+
+        # shortcut this.
+        if not force_external and (
+            (self.map.host_matching and host == self.server_name)
+            or (not self.map.host_matching and domain_part == self.subdomain)
+        ):
+            return "%s/%s" % (self.script_name.rstrip("/"), path.lstrip("/"))
+        return str(
+            "%s//%s%s/%s"
+            % (
+                self.url_scheme + ":" if self.url_scheme else "",
+                host,
+                self.script_name[:-1],
+                path.lstrip("/"),
+            )
+        )