/desktop/core/ext-py/Paste-1.7.2/paste/recursive.py
Python | 401 lines | 391 code | 0 blank | 10 comment | 4 complexity | 88568cde6b7a39d615908554f95de865 MD5 | raw file
- # (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
- # Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
- """
- Middleware to make internal requests and forward requests internally.
- When applied, several keys are added to the environment that will allow
- you to trigger recursive redirects and forwards.
- paste.recursive.include:
- When you call
- ``environ['paste.recursive.include'](new_path_info)`` a response
- will be returned. The response has a ``body`` attribute, a
- ``status`` attribute, and a ``headers`` attribute.
- paste.recursive.script_name:
- The ``SCRIPT_NAME`` at the point that recursive lives. Only
- paths underneath this path can be redirected to.
- paste.recursive.old_path_info:
- A list of previous ``PATH_INFO`` values from previous redirects.
- Raise ``ForwardRequestException(new_path_info)`` to do a forward
- (aborting the current request).
- """
- from cStringIO import StringIO
- import warnings
- __all__ = ['RecursiveMiddleware']
- __pudge_all__ = ['RecursiveMiddleware', 'ForwardRequestException']
- class CheckForRecursionMiddleware(object):
- def __init__(self, app, env):
- self.app = app
- self.env = env
-
- def __call__(self, environ, start_response):
- path_info = environ.get('PATH_INFO','')
- if path_info in self.env.get(
- 'paste.recursive.old_path_info', []):
- raise AssertionError(
- "Forwarding loop detected; %r visited twice (internal "
- "redirect path: %s)"
- % (path_info, self.env['paste.recursive.old_path_info']))
- old_path_info = self.env.setdefault('paste.recursive.old_path_info', [])
- old_path_info.append(self.env.get('PATH_INFO', ''))
- return self.app(environ, start_response)
- class RecursiveMiddleware(object):
- """
- A WSGI middleware that allows for recursive and forwarded calls.
- All these calls go to the same 'application', but presumably that
- application acts differently with different URLs. The forwarded
- URLs must be relative to this container.
- Interface is entirely through the ``paste.recursive.forward`` and
- ``paste.recursive.include`` environmental keys.
- """
- def __init__(self, application, global_conf=None):
- self.application = application
- def __call__(self, environ, start_response):
- environ['paste.recursive.forward'] = Forwarder(
- self.application,
- environ,
- start_response)
- environ['paste.recursive.include'] = Includer(
- self.application,
- environ,
- start_response)
- environ['paste.recursive.include_app_iter'] = IncluderAppIter(
- self.application,
- environ,
- start_response)
- my_script_name = environ.get('SCRIPT_NAME', '')
- environ['paste.recursive.script_name'] = my_script_name
- try:
- return self.application(environ, start_response)
- except ForwardRequestException, e:
- middleware = CheckForRecursionMiddleware(
- e.factory(self), environ)
- return middleware(environ, start_response)
- class ForwardRequestException(Exception):
- """
- Used to signal that a request should be forwarded to a different location.
-
- ``url``
- The URL to forward to starting with a ``/`` and relative to
- ``RecursiveMiddleware``. URL fragments can also contain query strings
- so ``/error?code=404`` would be a valid URL fragment.
-
- ``environ``
- An altertative WSGI environment dictionary to use for the forwarded
- request. If specified is used *instead* of the ``url_fragment``
-
- ``factory``
- If specifed ``factory`` is used instead of ``url`` or ``environ``.
- ``factory`` is a callable that takes a WSGI application object
- as the first argument and returns an initialised WSGI middleware
- which can alter the forwarded response.
- Basic usage (must have ``RecursiveMiddleware`` present) :
-
- .. code-block:: python
-
- from paste.recursive import ForwardRequestException
- def app(environ, start_response):
- if environ['PATH_INFO'] == '/hello':
- start_response("200 OK", [('Content-type', 'text/plain')])
- return ['Hello World!']
- elif environ['PATH_INFO'] == '/error':
- start_response("404 Not Found", [('Content-type', 'text/plain')])
- return ['Page not found']
- else:
- raise ForwardRequestException('/error')
-
- from paste.recursive import RecursiveMiddleware
- app = RecursiveMiddleware(app)
-
- If you ran this application and visited ``/hello`` you would get a
- ``Hello World!`` message. If you ran the application and visited
- ``/not_found`` a ``ForwardRequestException`` would be raised and the caught
- by the ``RecursiveMiddleware``. The ``RecursiveMiddleware`` would then
- return the headers and response from the ``/error`` URL but would display
- a ``404 Not found`` status message.
-
- You could also specify an ``environ`` dictionary instead of a url. Using
- the same example as before:
-
- .. code-block:: python
-
- def app(environ, start_response):
- ... same as previous example ...
- else:
- new_environ = environ.copy()
- new_environ['PATH_INFO'] = '/error'
- raise ForwardRequestException(environ=new_environ)
-
- Finally, if you want complete control over every aspect of the forward you
- can specify a middleware factory. For example to keep the old status code
- but use the headers and resposne body from the forwarded response you might
- do this:
-
- .. code-block:: python
- from paste.recursive import ForwardRequestException
- from paste.recursive import RecursiveMiddleware
- from paste.errordocument import StatusKeeper
- def app(environ, start_response):
- if environ['PATH_INFO'] == '/hello':
- start_response("200 OK", [('Content-type', 'text/plain')])
- return ['Hello World!']
- elif environ['PATH_INFO'] == '/error':
- start_response("404 Not Found", [('Content-type', 'text/plain')])
- return ['Page not found']
- else:
- def factory(app):
- return StatusKeeper(app, status='404 Not Found', url='/error')
- raise ForwardRequestException(factory=factory)
- app = RecursiveMiddleware(app)
- """
- def __init__(
- self,
- url=None,
- environ={},
- factory=None,
- path_info=None):
- # Check no incompatible options have been chosen
- if factory and url:
- raise TypeError(
- 'You cannot specify factory and a url in '
- 'ForwardRequestException')
- elif factory and environ:
- raise TypeError(
- 'You cannot specify factory and environ in '
- 'ForwardRequestException')
- if url and environ:
- raise TypeError(
- 'You cannot specify environ and url in '
- 'ForwardRequestException')
- # set the path_info or warn about its use.
- if path_info:
- if not url:
- warnings.warn(
- "ForwardRequestException(path_info=...) has been deprecated; please "
- "use ForwardRequestException(url=...)",
- DeprecationWarning, 2)
- else:
- raise TypeError('You cannot use url and path_info in ForwardRequestException')
- self.path_info = path_info
-
- # If the url can be treated as a path_info do that
- if url and not '?' in str(url):
- self.path_info = url
-
- # Base middleware
- class ForwardRequestExceptionMiddleware(object):
- def __init__(self, app):
- self.app = app
-
- # Otherwise construct the appropriate middleware factory
- if hasattr(self, 'path_info'):
- p = self.path_info
- def factory_(app):
- class PathInfoForward(ForwardRequestExceptionMiddleware):
- def __call__(self, environ, start_response):
- environ['PATH_INFO'] = p
- return self.app(environ, start_response)
- return PathInfoForward(app)
- self.factory = factory_
- elif url:
- def factory_(app):
- class URLForward(ForwardRequestExceptionMiddleware):
- def __call__(self, environ, start_response):
- environ['PATH_INFO'] = url.split('?')[0]
- environ['QUERY_STRING'] = url.split('?')[1]
- return self.app(environ, start_response)
- return URLForward(app)
- self.factory = factory_
- elif environ:
- def factory_(app):
- class EnvironForward(ForwardRequestExceptionMiddleware):
- def __call__(self, environ_, start_response):
- return self.app(environ, start_response)
- return EnvironForward(app)
- self.factory = factory_
- else:
- self.factory = factory
- class Recursive(object):
- def __init__(self, application, environ, start_response):
- self.application = application
- self.original_environ = environ.copy()
- self.previous_environ = environ
- self.start_response = start_response
- def __call__(self, path, extra_environ=None):
- """
- `extra_environ` is an optional dictionary that is also added
- to the forwarded request. E.g., ``{'HTTP_HOST': 'new.host'}``
- could be used to forward to a different virtual host.
- """
- environ = self.original_environ.copy()
- if extra_environ:
- environ.update(extra_environ)
- environ['paste.recursive.previous_environ'] = self.previous_environ
- base_path = self.original_environ.get('SCRIPT_NAME')
- if path.startswith('/'):
- assert path.startswith(base_path), (
- "You can only forward requests to resources under the "
- "path %r (not %r)" % (base_path, path))
- path = path[len(base_path)+1:]
- assert not path.startswith('/')
- path_info = '/' + path
- environ['PATH_INFO'] = path_info
- environ['REQUEST_METHOD'] = 'GET'
- environ['CONTENT_LENGTH'] = '0'
- environ['CONTENT_TYPE'] = ''
- environ['wsgi.input'] = StringIO('')
- return self.activate(environ)
- def activate(self, environ):
- raise NotImplementedError
- def __repr__(self):
- return '<%s.%s from %s>' % (
- self.__class__.__module__,
- self.__class__.__name__,
- self.original_environ.get('SCRIPT_NAME') or '/')
- class Forwarder(Recursive):
- """
- The forwarder will try to restart the request, except with
- the new `path` (replacing ``PATH_INFO`` in the request).
- It must not be called after and headers have been returned.
- It returns an iterator that must be returned back up the call
- stack, so it must be used like:
-
- .. code-block:: python
- return environ['paste.recursive.forward'](path)
- Meaningful transformations cannot be done, since headers are
- sent directly to the server and cannot be inspected or
- rewritten.
- """
- def activate(self, environ):
- warnings.warn(
- "recursive.Forwarder has been deprecated; please use "
- "ForwardRequestException",
- DeprecationWarning, 2)
- return self.application(environ, self.start_response)
-
- class Includer(Recursive):
- """
- Starts another request with the given path and adding or
- overwriting any values in the `extra_environ` dictionary.
- Returns an IncludeResponse object.
- """
-
- def activate(self, environ):
- response = IncludedResponse()
- def start_response(status, headers, exc_info=None):
- if exc_info:
- raise exc_info[0], exc_info[1], exc_info[2]
- response.status = status
- response.headers = headers
- return response.write
- app_iter = self.application(environ, start_response)
- try:
- for s in app_iter:
- response.write(s)
- finally:
- if hasattr(app_iter, 'close'):
- app_iter.close()
- response.close()
- return response
- class IncludedResponse(object):
- def __init__(self):
- self.headers = None
- self.status = None
- self.output = StringIO()
- self.str = None
- def close(self):
- self.str = self.output.getvalue()
- self.output.close()
- self.output = None
- def write(self, s):
- assert self.output is not None, (
- "This response has already been closed and no further data "
- "can be written.")
- self.output.write(s)
- def __str__(self):
- return self.body
- def body__get(self):
- if self.str is None:
- return self.output.getvalue()
- else:
- return self.str
- body = property(body__get)
- class IncluderAppIter(Recursive):
- """
- Like Includer, but just stores the app_iter response
- (be sure to call close on the response!)
- """
- def activate(self, environ):
- response = IncludedAppIterResponse()
- def start_response(status, headers, exc_info=None):
- if exc_info:
- raise exc_info[0], exc_info[1], exc_info[2]
- response.status = status
- response.headers = headers
- return response.write
- app_iter = self.application(environ, start_response)
- response.app_iter = app_iter
- return response
- class IncludedAppIterResponse(object):
- def __init__(self):
- self.status = None
- self.headers = None
- self.accumulated = []
- self.app_iter = None
- self._closed = False
- def close(self):
- assert not self._closed, (
- "Tried to close twice")
- if hasattr(self.app_iter, 'close'):
- self.app_iter.close()
-
- def write(self, s):
- self.accumulated.append
- def make_recursive_middleware(app, global_conf):
- return RecursiveMiddleware(app)
- make_recursive_middleware.__doc__ = __doc__