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# Copyright (C) 2006-2010 Canonical Ltd
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# This program is free software; you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation; either version 2 of the License, or
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# (at your option) any later version.
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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"""WSGI application for bzr HTTP smart server.
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For more information about WSGI, see PEP 333:
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http://www.python.org/dev/peps/pep-0333/
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from __future__ import absolute_import
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from ...sixish import (
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from ...smart import medium
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from ...transport import chroot, get_transport
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from ...urlutils import local_path_to_url
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def make_app(root, prefix, path_var='REQUEST_URI', readonly=True,
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load_plugins=True, enable_logging=True):
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"""Convenience function to construct a WSGI bzr smart server.
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:param root: a local path that requests will be relative to.
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:param prefix: See RelpathSetter.
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:param path_var: See RelpathSetter.
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local_url = local_path_to_url(root)
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base_transport = get_transport('readonly+' + local_url)
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base_transport = get_transport(local_url)
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from ...plugin import load_plugins
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breezy.trace.enable_default_logging()
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app = SmartWSGIApp(base_transport, prefix)
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app = RelpathSetter(app, '', path_var)
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class RelpathSetter(object):
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"""WSGI middleware to set 'breezy.relpath' in the environ.
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Different servers can invoke a SmartWSGIApp in different ways. This
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middleware allows an adminstrator to configure how to the SmartWSGIApp will
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determine what path it should be serving for a given request for many common
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For example, a request for "/some/prefix/repo/branch/.bzr/smart" received by
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a typical Apache and mod_fastcgi configuration will set `REQUEST_URI` to
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"/some/prefix/repo/branch/.bzr/smart". A RelpathSetter with
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prefix="/some/prefix/" and path_var="REQUEST_URI" will set that request's
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'breezy.relpath' variable to "repo/branch".
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def __init__(self, app, prefix='', path_var='REQUEST_URI'):
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:param app: WSGI app to wrap, e.g. a SmartWSGIApp instance.
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:param path_var: the variable in the WSGI environ to calculate the
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'breezy.relpath' variable from.
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:param prefix: a prefix to strip from the variable specified in
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path_var before setting 'breezy.relpath'.
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self.path_var = path_var
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def __call__(self, environ, start_response):
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path = environ[self.path_var]
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suffix = '/.bzr/smart'
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if not (path.startswith(self.prefix) and path.endswith(suffix)):
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start_response('404 Not Found', [])
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environ['breezy.relpath'] = path[len(self.prefix):-len(suffix)]
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return self.app(environ, start_response)
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class SmartWSGIApp(object):
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"""A WSGI application for the bzr smart server."""
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def __init__(self, backing_transport, root_client_path='/'):
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:param backing_transport: a transport. Requests will be processed
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relative to this transport.
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:param root_client_path: the client path that maps to the root of
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backing_transport. This is used to interpret relpaths received from
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# Use a ChrootServer so that this web application won't
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# accidentally let people access locations they shouldn't.
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# e.g. consider a smart server request for "get /etc/passwd" or
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self.chroot_server = chroot.ChrootServer(backing_transport)
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self.chroot_server.start_server()
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self.backing_transport = get_transport(self.chroot_server.get_url())
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self.root_client_path = root_client_path
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# While the chroot server can technically be torn down at this point,
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# as all it does is remove the scheme registration from transport's
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# protocol dictionary, we don't *just in case* there are parts of
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# breezy that will invoke 'get_transport' on urls rather than cloning
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# around the existing transport.
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#self.chroot_server.stop_server()
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def __call__(self, environ, start_response):
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"""WSGI application callable."""
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if environ['REQUEST_METHOD'] != 'POST':
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start_response('405 Method not allowed', [('Allow', 'POST')])
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relpath = environ['breezy.relpath']
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if not relpath.startswith('/'):
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relpath = '/' + relpath
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if not relpath.endswith('/'):
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# Compare the HTTP path (relpath) and root_client_path, and calculate
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# new relpath and root_client_path accordingly, to be used to build the
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if relpath.startswith(self.root_client_path):
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# The relpath traverses all of the mandatory root client path.
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# Remove the root_client_path from the relpath, and set
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# adjusted_tcp to None to tell the request handler that no further
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# path translation is required.
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adjusted_relpath = relpath[len(self.root_client_path):]
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elif self.root_client_path.startswith(relpath):
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# The relpath traverses some of the mandatory root client path.
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# Subtract the relpath from the root_client_path, and set the
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adjusted_rcp = '/' + self.root_client_path[len(relpath):]
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adjusted_relpath = '.'
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adjusted_rcp = self.root_client_path
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adjusted_relpath = relpath
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if adjusted_relpath.startswith('/'):
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adjusted_relpath = adjusted_relpath[1:]
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if adjusted_relpath.startswith('/'):
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raise AssertionError(adjusted_relpath)
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transport = self.backing_transport.clone(adjusted_relpath)
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out_buffer = BytesIO()
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request_data_length = int(environ['CONTENT_LENGTH'])
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request_data_bytes = environ['wsgi.input'].read(request_data_length)
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smart_protocol_request = self.make_request(
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transport, out_buffer.write, request_data_bytes, adjusted_rcp)
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if smart_protocol_request.next_read_size() != 0:
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# The request appears to be incomplete, or perhaps it's just a
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# newer version we don't understand. Regardless, all we can do
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# is return an error response in the format of our version of the
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response_data = 'error\x01incomplete request\n'
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response_data = out_buffer.getvalue()
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headers = [('Content-type', 'application/octet-stream')]
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headers.append(("Content-Length", str(len(response_data))))
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start_response('200 OK', headers)
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return [response_data]
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def make_request(self, transport, write_func, request_bytes, rcp):
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protocol_factory, unused_bytes = medium._get_protocol_factory_for_bytes(
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server_protocol = protocol_factory(
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transport, write_func, rcp, self.backing_transport)
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server_protocol.accept_bytes(unused_bytes)
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return server_protocol