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webapp2.py
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# -*- coding: utf-8 -*-
# Copyright 2011 webapp2 AUTHORS.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
webapp2
=======
Taking Google App Engine's webapp to the next level!
:copyright: 2011 webapp2 AUTHORS.
:license: Apache Software License, see LICENSE for details.
"""
import cgi
from collections import OrderedDict
import inspect
import logging
import os
import re
import sys
import threading
import traceback
from wsgiref import handlers
import six
from six.moves import cStringIO
from six.moves.urllib.parse import quote
from six.moves.urllib.parse import unquote
from six.moves.urllib.parse import urlencode
from six.moves.urllib.parse import urljoin
from six.moves.urllib.parse import urlunsplit
import webob
from webob import exc
_webapp = _webapp_util = _local = None
try: # pragma: no cover
# WebOb < 1.0 (App Engine Python 2.5).
from webob.statusreasons import status_reasons
from webob.headerdict import HeaderDict as BaseResponseHeaders
except ImportError: # pragma: no cover
# WebOb >= 1.0.
from webob.util import status_reasons
from webob.headers import ResponseHeaders as BaseResponseHeaders
try: # pragma no cover
import html
except ImportError:
html = cgi
# google.appengine.ext.webapp imports webapp2 in the
# App Engine Python 2.7 runtime.
if os.environ.get('APPENGINE_RUNTIME') != 'python27': # pragma: no cover
try:
from google.appengine.ext import webapp as _webapp
except ImportError: # pragma: no cover
# Running webapp2 outside of GAE.
pass
try: # pragma: no cover
# Thread-local variables container.
from webapp2_extras import local
_local = local.Local()
except ImportError: # pragma: no cover
logging.warning("webapp2_extras.local is not available "
"so webapp2 won't be thread-safe!")
__version_info__ = (3, 0, 0)
__version__ = '.'.join(str(n) for n in __version_info__)
#: Base HTTP exception, set here as public interface.
HTTPException = exc.HTTPException
#: Regex for route definitions.
_route_re = re.compile(r"""
\< # The exact character "<"
([a-zA-Z_]\w*)? # The optional variable name
(?:\:([^\>]*))? # The optional :regex part
\> # The exact character ">"
""", re.VERBOSE)
#: Regex extract charset from environ.
_charset_re = re.compile(r';\s*charset=([^;]*)', re.I)
#: To show exceptions in debug mode.
_debug_template = """<html>
<head>
<title>Internal Server Error</title>
<style>
body {
padding: 20px;
font-family: arial, sans-serif;
font-size: 14px;
}
pre {
background: #F2F2F2;
padding: 10px;
}
</style>
</head>
<body>
<h1>Internal Server Error</h1>
<p>The server has either erred or is incapable of performing
the requested operation.</p>
<pre>%s</pre>
</body>
</html>"""
# Set same default messages from webapp plus missing ones.
_webapp_status_reasons = {
203: 'Non-Authoritative Information',
302: 'Moved Temporarily',
306: 'Unused',
408: 'Request Time-out',
414: 'Request-URI Too Large',
504: 'Gateway Time-out',
505: 'HTTP Version not supported',
}
status_reasons.update(_webapp_status_reasons)
for code, message in six.iteritems(_webapp_status_reasons):
cls = exc.status_map.get(code)
if cls:
cls.title = message
class Request(webob.Request):
"""Abstraction for an HTTP request.
Most extra methods and attributes are ported from webapp. Check the
`WebOb`_ documentation for the ones not listed here.
"""
#: A reference to the active :class:`WSGIApplication` instance.
app = None
#: A reference to the active :class:`Response` instance.
response = None
#: A reference to the matched :class:`Route`.
route = None
#: The matched route positional arguments.
route_args = None
#: The matched route keyword arguments.
route_kwargs = None
#: A dictionary to register objects used during the request lifetime.
registry = None
# Attributes from webapp.
request_body_tempfile_limit = 0
#: Charset provided in requests @CONTENT_TYPE.
_request_charset = None
uri = property(lambda self: self.url)
query = property(lambda self: self.query_string)
def __init__(self, environ, *args, **kwargs):
"""Constructs a Request object from a WSGI environment.
:param environ:
A WSGI-compliant environment dictionary.
"""
if kwargs.get('charset') is None and not hasattr(webob, '__version__'):
# webob 0.9 didn't have a __version__ attribute and also defaulted
# to None rather than UTF-8 if no charset was provided. Providing a
# default charset is required for backwards compatibility.
match = _charset_re.search(environ.get('CONTENT_TYPE', ''))
if match:
self._request_charset = (
match.group(1).lower().strip().strip('"').strip())
kwargs['charset'] = 'utf-8'
super(Request, self).__init__(environ, *args, **kwargs)
self.registry = {}
def get(self, argument_name, default_value='', allow_multiple=False):
"""Returns the query or POST argument with the given name.
We parse the query string and POST payload lazily, so this will be a
slower operation on the first call.
:param argument_name:
The name of the query or POST argument.
:param default_value:
The value to return if the given argument is not present.
:param allow_multiple:
Return a list of values with the given name (deprecated).
:returns:
Return the value with the given name given in the request. If there
are multiple values, this will only return the first one. Use
`get_all()` to get multiple values.
"""
param_value = self.get_all(argument_name)
if len(param_value) > 0:
return param_value[0]
else:
return default_value
def __getitem__(self, argument_name):
"""Provides dict-like access to attributes.
:param argument_name:
The name of the query or POST argument.
:returns:
Return the value with the given name given in the request. If there
are multiple values, this will only return the first one. Use
`get_all()` to get multiple values.
"""
return self.get(argument_name)
def get_all(self, argument_name, default_value=None):
"""Returns a list of query or POST arguments with the given name.
We parse the query string and POST payload lazily, so this will be a
slower operation on the first call.
:param argument_name:
The name of the query or POST argument.
:param default_value:
The value to return if the given argument is not present,
None may not be used as a default, if it is then an empty
list will be returned instead.
:returns:
A (possibly empty) list of values.
"""
if self.charset and not six.PY3:
argument_name = argument_name.encode(self.charset)
if default_value is None:
default_value = []
param_value = self.params.getall(argument_name)
if param_value is None or len(param_value) == 0:
return default_value
for i in six.moves.range(len(param_value)):
if isinstance(param_value[i], cgi.FieldStorage):
param_value[i] = param_value[i].value
return param_value
def arguments(self):
"""Returns a list of the arguments provided in the query and/or POST.
The return value is an ordered list of strings.
"""
return list(OrderedDict.fromkeys(self.params.keys()))
def get_range(self, name, min_value=None, max_value=None, default=0):
"""Parses the given int argument, limiting it to the given range.
:param name:
The name of the argument.
:param min_value:
The minimum int value of the argument (if any).
:param max_value:
The maximum int value of the argument (if any).
:param default:
The default value of the argument if it is not given.
:returns:
An int within the given range for the argument.
"""
value = self.get(name, default)
if value is None:
return value
try:
value = int(value)
except ValueError:
value = default
if value is not None:
if max_value is not None:
value = min(value, max_value)
if min_value is not None:
value = max(value, min_value)
return value
@classmethod
def blank(cls, path, environ=None, base_url=None,
headers=None, **kwargs): # pragma: no cover
"""Adds parameters compatible with WebOb > 1.2: POST and **kwargs."""
try:
request = super(Request, cls).blank(
path,
environ=environ,
base_url=base_url,
headers=headers,
**kwargs
)
if cls._request_charset and not cls._request_charset == 'utf-8':
return request.decode(cls._request_charset)
return request
except TypeError:
if not kwargs:
raise
data = kwargs.pop('POST', None)
if data is not None:
environ = environ or {}
environ['REQUEST_METHOD'] = 'POST'
if hasattr(data, 'items'):
data = list(data.items())
if not isinstance(data, str):
data = urlencode(data)
environ['wsgi.input'] = cStringIO(data)
environ['webob.is_body_seekable'] = True
environ['CONTENT_LENGTH'] = str(len(data))
environ['CONTENT_TYPE'] = 'application/x-www-form-urlencoded'
base = super(Request, cls).blank(path, environ=environ,
base_url=base_url, headers=headers)
if kwargs:
obj = cls(base.environ, **kwargs)
obj.headers.update(base.headers)
return obj
else:
return base
class ResponseHeaders(BaseResponseHeaders):
"""Implements methods from ``wsgiref.headers.Headers``, used by webapp."""
get_all = BaseResponseHeaders.getall
def add_header(self, _name, _value, **_params):
"""Extended header setting.
_name is the header field to add. keyword arguments can be used to set
additional parameters for the header field, with underscores converted
to dashes. Normally the parameter will be added as key="value" unless
value is None, in which case only the key will be added.
Example::
h.add_header('content-disposition', 'attachment',
filename='bud.gif')
Note that unlike the corresponding 'email.message' method, this does
*not* handle '(charset, language, value)' tuples: all values must be
strings or None.
"""
parts = []
if _value is not None:
parts.append(_value)
for k, v in _params.items():
k = k.replace('_', '-')
if v is not None and len(v) > 0:
v = v.replace('\\', '\\\\').replace('"', r'\"')
parts.append('%s="%s"' % (k, v))
else:
parts.append(k)
self.add(_name, '; '.join(parts))
def __str__(self):
"""Returns the formatted headers ready for HTTP transmission."""
return '\r\n'.join(['%s: %s' % v for v in self.items()] + ['', ''])
class Response(webob.Response):
"""Abstraction for an HTTP response.
Most extra methods and attributes are ported from webapp. Check the
`WebOb`_ documentation for the ones not listed here.
Differences from webapp.Response:
- ``out`` is not a ``StringIO.StringIO`` instance. Instead it is the
response itself, as it has the method ``write()``.
- As in WebOb, ``status`` is the code plus message, e.g., '200 OK', while
in webapp it is the integer code. The status code as an integer is
available in ``status_int``, and the status message is available in
``status_message``.
- ``response.headers`` raises an exception when a key that doesn't exist
is accessed or deleted, differently from ``wsgiref.headers.Headers``.
"""
#: Default charset as in webapp.
default_charset = 'utf-8'
def __init__(self, *args, **kwargs):
"""Constructs a response with the default settings."""
super(Response, self).__init__(*args, **kwargs)
self.headers['Cache-Control'] = 'no-cache'
@property
def out(self):
"""A reference to the Response instance itself, for compatibility with
webapp only: webapp uses `Response.out.write()`, so we point `out` to
`self` and it will use `Response.write()`.
"""
return self
def write(self, text):
"""Appends a text to the response body."""
# webapp uses StringIO as Response.out, so we need to convert anything
# that is not str or unicode to string to keep same behavior.
if six.PY3 and isinstance(text, bytes):
text = text.decode(self.default_charset)
if not isinstance(text, six.string_types):
text = six.text_type(text)
if isinstance(text, six.text_type) and not self.charset:
self.charset = self.default_charset
super(Response, self).write(text)
def _set_status(self, value):
"""The status string, including code and message."""
message = None
# Accept long because urlfetch in App Engine returns codes as longs.
if isinstance(value, six.integer_types):
code = int(value)
else:
if isinstance(value, six.text_type):
# Status messages have to be ASCII safe, so this is OK.
value = str(value)
if not isinstance(value, str):
raise TypeError(
'You must set status to a string or integer (not %s)'
% type(value))
parts = value.split(' ', 1)
code = int(parts[0])
if len(parts) == 2:
message = parts[1]
message = message or Response.http_status_message(code)
self._status = '%d %s' % (code, message)
def _get_status(self):
return self._status
status = property(_get_status, _set_status, doc=_set_status.__doc__)
def set_status(self, code, message=None):
"""Sets the HTTP status code of this response.
:param code:
The HTTP status string to use
:param message:
A status string. If none is given, uses the default from the
HTTP/1.1 specification.
"""
if message:
self.status = '%d %s' % (code, message)
else:
self.status = code
def _get_status_message(self):
"""The response status message, as a string."""
return self.status.split(' ', 1)[1]
def _set_status_message(self, message):
self.status = '%d %s' % (self.status_int, message)
status_message = property(_get_status_message, _set_status_message,
doc=_get_status_message.__doc__)
def _get_headers(self):
"""The headers as a dictionary-like object."""
if self._headers is None:
self._headers = ResponseHeaders.view_list(self.headerlist)
return self._headers
def _set_headers(self, value):
if hasattr(value, 'items'):
value = list(value.items())
elif not isinstance(value, list):
raise TypeError('Response headers must be a list or dictionary.')
self.headerlist = value
self._headers = None
headers = property(_get_headers, _set_headers, doc=_get_headers.__doc__)
def has_error(self):
"""Indicates whether the response was an error response."""
return self.status_int >= 400
def clear(self):
"""Clears all data written to the output stream so that it is empty."""
self.body = b''
def wsgi_write(self, start_response):
"""Writes this response using the given WSGI function.
This is only here for compatibility with ``webapp.WSGIApplication``.
:param start_response:
The WSGI-compatible start_response function.
"""
if (self.headers.get('Cache-Control') == 'no-cache' and
not self.headers.get('Expires')):
self.headers['Expires'] = 'Fri, 01 Jan 1990 00:00:00 GMT'
self.headers['Content-Length'] = str(len(self.body))
write = start_response(self.status, self.headerlist)
write(self.body)
@staticmethod
def http_status_message(code):
"""Returns the default HTTP status message for the given code.
:param code:
The HTTP code for which we want a message.
"""
message = status_reasons.get(code)
if not message:
raise KeyError('Invalid HTTP status code: %d' % code)
return message
class RequestHandler(object):
"""Base HTTP request handler.
Implements most of ``webapp.RequestHandler`` interface.
"""
#: A :class:`Request` instance.
request = None
#: A :class:`Response` instance.
response = None
#: A :class:`WSGIApplication` instance.
app = None
def __init__(self, request=None, response=None):
"""Initializes this request handler with the given WSGI application,
Request and Response.
When instantiated by ``webapp.WSGIApplication``, request and response
are not set on instantiation. Instead, initialize() is called right
after the handler is created to set them.
Also in webapp dispatching is done by the WSGI app, while webapp2
does it here to allow more flexibility in extended classes: handlers
can wrap :meth:`dispatch` to check for conditions before executing the
requested method and/or post-process the response.
.. note::
Parameters are optional only to support webapp's constructor which
doesn't take any arguments. Consider them as required.
:param request:
A :class:`Request` instance.
:param response:
A :class:`Response` instance.
"""
self.initialize(request, response)
def initialize(self, request, response):
"""Initializes this request handler with the given WSGI application,
Request and Response.
:param request:
A :class:`Request` instance.
:param response:
A :class:`Response` instance.
"""
self.request = request
self.response = response
self.app = WSGIApplication.active_instance
def dispatch(self):
"""Dispatches the request.
This will first check if there's a handler_method defined in the
matched route, and if not it'll use the method correspondent to the
request method (``get()``, ``post()`` etc).
"""
request = self.request
method_name = request.route.handler_method
if not method_name:
method_name = _normalize_handler_method(request.method)
method = getattr(self, method_name, None)
if method is None:
# 405 Method Not Allowed.
# The response MUST include an Allow header containing a
# list of valid methods for the requested resource.
# http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.6
valid = ', '.join(_get_handler_methods(self))
self.abort(405, headers=[('Allow', valid)])
# The handler only receives *args if no named variables are set.
args, kwargs = request.route_args, request.route_kwargs
if kwargs:
args = ()
try:
return method(*args, **kwargs)
except Exception as e:
return self.handle_exception(e, self.app.debug)
def error(self, code):
"""Clears the response and sets the given HTTP status code.
This doesn't stop code execution; for this, use :meth:`abort`.
:param code:
HTTP status error code (e.g., 501).
"""
self.response.status = code
self.response.clear()
def abort(self, code, *args, **kwargs):
"""Raises an :class:`HTTPException`.
This stops code execution, leaving the HTTP exception to be handled
by an exception handler.
:param code:
HTTP status code (e.g., 404).
:param args:
Positional arguments to be passed to the exception class.
:param kwargs:
Keyword arguments to be passed to the exception class.
"""
abort(code, *args, **kwargs)
def redirect(self, uri, permanent=False, abort=False, code=None,
body=None):
"""Issues an HTTP redirect to the given relative URI.
The arguments are described in :func:`redirect`.
"""
return redirect(uri, permanent=permanent, abort=abort, code=code,
body=body, request=self.request,
response=self.response)
def redirect_to(self, _name, _permanent=False, _abort=False, _code=None,
_body=None, *args, **kwargs):
"""Convenience method mixing :meth:`redirect` and :meth:`uri_for`.
The arguments are described in :func:`redirect` and :func:`uri_for`.
"""
uri = self.uri_for(_name, *args, **kwargs)
return self.redirect(uri, permanent=_permanent, abort=_abort,
code=_code, body=_body)
def uri_for(self, _name, *args, **kwargs):
"""Returns a URI for a named :class:`Route`.
.. seealso:: :meth:`Router.build`.
"""
return self.app.router.build(self.request, _name, args, kwargs)
# Alias.
url_for = uri_for
def handle_exception(self, exception, debug):
"""Called if this handler throws an exception during execution.
The default behavior is to re-raise the exception to be handled by
:meth:`WSGIApplication.handle_exception`.
:param exception:
The exception that was thrown.
:param debug_mode:
True if the web application is running in debug mode.
"""
raise
class RedirectHandler(RequestHandler):
"""Redirects to the given URI for all GET requests.
This is intended to be used when defining URI routes. You must provide at
least the keyword argument *url* in the route default values. Example::
def get_redirect_url(handler, *args, **kwargs):
return handler.uri_for('new-route-name')
app = WSGIApplication([
Route('/old-url', RedirectHandler, defaults={'_uri': '/new-url'}),
Route('/other-old-url', RedirectHandler, defaults={
'_uri': get_redirect_url}),
])
Based on idea from `Tornado`_.
"""
def get(self, *args, **kwargs):
"""Performs a redirect.
Two keyword arguments can be passed through the URI route:
- **_uri**: A URI string or a callable that returns a URI. The callable
is called passing ``(handler, *args, **kwargs)`` as arguments.
- **_code**: The redirect status code. Default is 301 (permanent
redirect).
"""
uri = kwargs.pop('_uri', '/')
permanent = kwargs.pop('_permanent', True)
code = kwargs.pop('_code', None)
func = getattr(uri, '__call__', None)
if func:
uri = func(self, *args, **kwargs)
self.redirect(uri, permanent=permanent, code=code)
class cached_property(object):
"""A decorator that converts a function into a lazy property.
The function wrapped is called the first time to retrieve the result
and then that calculated result is used the next time you access
the value::
class Foo(object):
@cached_property
def foo(self):
# calculate something important here
return 42
The class has to have a `__dict__` in order for this property to
work.
.. note:: Implementation detail: this property is implemented as non-data
descriptor. non-data descriptors are only invoked if there is
no entry with the same name in the instance's __dict__.
this allows us to completely get rid of the access function call
overhead. If one choses to invoke __get__ by hand the property
will still work as expected because the lookup logic is replicated
in __get__ for manual invocation.
This class was ported from `Werkzeug`_ and `Flask`_.
"""
_default_value = object()
def __init__(self, func, name=None, doc=None):
self.__name__ = name or func.__name__
self.__module__ = func.__module__
self.__doc__ = doc or func.__doc__
self.func = func
self.lock = threading.RLock()
def __get__(self, obj, type=None):
if obj is None:
return self
with self.lock:
value = obj.__dict__.get(self.__name__, self._default_value)
if value is self._default_value:
value = self.func(obj)
obj.__dict__[self.__name__] = value
return value
class BaseRoute(object):
"""Interface for URI routes."""
#: The regex template.
template = None
#: Route name, used to build URIs.
name = None
#: True if this route is only used for URI generation and never matches.
build_only = False
#: The handler or string in dotted notation to be lazily imported.
handler = None
#: The custom handler method, if handler is a class.
handler_method = None
#: The handler, imported and ready for dispatching.
handler_adapter = None
def __init__(self, template, handler=None, name=None, build_only=False):
"""Initializes this route.
:param template:
A regex to be matched.
:param handler:
A callable or string in dotted notation to be lazily imported,
e.g., ``'my.module.MyHandler'`` or ``'my.module.my_function'``.
:param name:
The name of this route, used to build URIs based on it.
:param build_only:
If True, this route never matches and is used only to build URIs.
"""
if build_only and name is None:
raise ValueError(
"Route %r is build_only but doesn't have a name." % self)
self.template = template
self.handler = handler
self.name = name
self.build_only = build_only
def match(self, request):
"""Matches all routes against a request object.
The first one that matches is returned.
:param request:
A :class:`Request` instance.
:returns:
A tuple ``(route, args, kwargs)`` if a route matched, or None.
"""
raise NotImplementedError()
def build(self, request, args, kwargs):
"""Returns a URI for this route.
:param request:
The current :class:`Request` object.
:param args:
Tuple of positional arguments to build the URI.
:param kwargs:
Dictionary of keyword arguments to build the URI.
:returns:
An absolute or relative URI.
"""
raise NotImplementedError()
def get_routes(self):
"""Generator to get all routes from a route.
:yields:
This route or all nested routes that it contains.
"""
yield self
def get_match_routes(self):
"""Generator to get all routes that can be matched from a route.
Match routes must implement :meth:`match`.
:yields:
This route or all nested routes that can be matched.
"""
if not self.build_only:
yield self
def get_build_routes(self):
"""Generator to get all routes that can be built from a route.
Build routes must implement :meth:`build`.
:yields:
A tuple ``(name, route)`` for all nested routes that can be built.
"""
if self.name is not None:
yield self.name, self
class SimpleRoute(BaseRoute):
"""A route that is compatible with webapp's routing mechanism.
URI building is not implemented as webapp has rudimentar support for it,
and this is the most unknown webapp feature anyway.
"""
@cached_property
def regex(self):
"""Lazy regex compiler."""
if not self.template.startswith('^'):
self.template = '^' + self.template
if not self.template.endswith('$'):
self.template += '$'
return re.compile(self.template)
def match(self, request):
"""Matches this route against the current request.
.. seealso:: :meth:`BaseRoute.match`.
"""
match = self.regex.match(unquote(request.path))
if match:
return self, match.groups(), {}
def __repr__(self):
return '<SimpleRoute(%r, %r)>' % (self.template, self.handler)
class Route(BaseRoute):
"""A route definition that maps a URI path to a handler.
The initial concept was based on `Another Do-It-Yourself Framework`_, by
Ian Bicking.
"""
#: Default parameters values.
defaults = None
#: Sequence of allowed HTTP methods. If not set, all methods are allowed.
methods = None
#: Sequence of allowed URI schemes. If not set, all schemes are allowed.
schemes = None
# Lazy properties extracted from the route template.
regex = None
reverse_template = None
variables = None
args_count = 0
kwargs_count = 0
def __init__(self, template, handler=None, name=None, defaults=None,
build_only=False, handler_method=None, methods=None,
schemes=None):
"""Initializes this route.
:param template:
A route template to match against the request path. A template
can have variables enclosed by ``<>`` that define a name, a
regular expression or both. Examples:
================= ==================================
Format Example
================= ==================================
``<name>`` ``'/blog/<year>/<month>'``
``<:regex>`` ``'/blog/<:\d{4}>/<:\d{2}>'``
``<name:regex>`` ``'/blog/<year:\d{4}>/<month:\d{2}>'``
================= ==================================
The same template can mix parts with name, regular expression or
both.
If the name is set, the value of the matched regular expression
is passed as keyword argument to the handler. Otherwise it is
passed as positional argument.
If only the name is set, it will match anything except a slash.
So these routes are equivalent::
Route('/<user_id>/settings', handler=SettingsHandler,
name='user-settings')
Route('/<user_id:[^/]+>/settings', handler=SettingsHandler,
name='user-settings')
.. note::
The handler only receives ``*args`` if no named variables are
set. Otherwise, the handler only receives ``**kwargs``. This
allows you to set regular expressions that are not captured:
just mix named and unnamed variables and the handler will
only receive the named ones.
:param handler:
A callable or string in dotted notation to be lazily imported,
e.g., ``'my.module.MyHandler'`` or ``'my.module.my_function'``.
It is possible to define a method if the callable is a class,
separating it by a colon: ``'my.module.MyHandler:my_method'``.
This is a shortcut and has the same effect as defining the
`handler_method` parameter.
:param name:
The name of this route, used to build URIs based on it.
:param defaults:
Default or extra keywords to be returned by this route. Values
also present in the route variables are used to build the URI
when they are missing.
:param build_only:
If True, this route never matches and is used only to build URIs.
:param handler_method:
The name of a custom handler method to be called, in case `handler`
is a class. If not defined, the default behavior is to call the
handler method correspondent to the HTTP request method in lower
case (e.g., `get()`, `post()` etc).
:param methods:
A sequence of HTTP methods. If set, the route will only match if
the request method is allowed.
:param schemes:
A sequence of URI schemes, e.g., ``['http']`` or ``['https']``.
If set, the route will only match requests with these schemes.
"""
super(Route, self).__init__(template, handler=handler, name=name,
build_only=build_only)
self.defaults = defaults or {}
self.methods = methods
self.schemes = schemes
if isinstance(handler, six.string_types) and ':' in handler:
if handler_method:
raise ValueError(
"If handler_method is defined in a Route, handler "
"can't have a colon (got %r)." % handler)