~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006-2010 Canonical Ltd

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

"""WSGI application for bzr HTTP smart server.

For more information about WSGI, see PEP 333:

    http://www.python.org/dev/peps/pep-0333/

"""

from __future__ import absolute_import

from cStringIO import StringIO

from bzrlib.smart import medium

from bzrlib.transport import chroot, get_transport

from bzrlib.urlutils import local_path_to_url

def make_app(root, prefix, path_var='REQUEST_URI', readonly=True,

    load_plugins=True, enable_logging=True):

    """Convenience function to construct a WSGI bzr smart server.

    :param root: a local path that requests will be relative to.

    :param prefix: See RelpathSetter.

    :param path_var: See RelpathSetter.

    """

    local_url = local_path_to_url(root)

    if readonly:

        base_transport = get_transport('readonly+' + local_url)

    else:

        base_transport = get_transport(local_url)

    if load_plugins:

        from bzrlib.plugin import load_plugins

        load_plugins()

    if enable_logging:

        import bzrlib.trace

        bzrlib.trace.enable_default_logging()

    app = SmartWSGIApp(base_transport, prefix)

    app = RelpathSetter(app, '', path_var)

    return app

class RelpathSetter(object):

    """WSGI middleware to set 'bzrlib.relpath' in the environ.

    Different servers can invoke a SmartWSGIApp in different ways.  This

    middleware allows an adminstrator to configure how to the SmartWSGIApp will

    determine what path it should be serving for a given request for many common

    situations.

    For example, a request for "/some/prefix/repo/branch/.bzr/smart" received by

    a typical Apache and mod_fastcgi configuration will set `REQUEST_URI` to

    "/some/prefix/repo/branch/.bzr/smart".  A RelpathSetter with

    prefix="/some/prefix/" and path_var="REQUEST_URI" will set that request's

    'bzrlib.relpath' variable to "repo/branch".

    """

    def __init__(self, app, prefix='', path_var='REQUEST_URI'):

        """Constructor.

        :param app: WSGI app to wrap, e.g. a SmartWSGIApp instance.

        :param path_var: the variable in the WSGI environ to calculate the

            'bzrlib.relpath' variable from.

        :param prefix: a prefix to strip from the variable specified in

            path_var before setting 'bzrlib.relpath'.

        """

        self.app = app

        self.prefix = prefix

        self.path_var = path_var

    def __call__(self, environ, start_response):

        path = environ[self.path_var]

        suffix = '/.bzr/smart'

        if not (path.startswith(self.prefix) and path.endswith(suffix)):

            start_response('404 Not Found', [])

            return []

        environ['bzrlib.relpath'] = path[len(self.prefix):-len(suffix)]

        return self.app(environ, start_response)

class SmartWSGIApp(object):

    """A WSGI application for the bzr smart server."""

    def __init__(self, backing_transport, root_client_path='/'):

        """Constructor.

        :param backing_transport: a transport.  Requests will be processed

            relative to this transport.

        :param root_client_path: the client path that maps to the root of

            backing_transport.  This is used to interpret relpaths received from

            the client.

        """

        # Use a ChrootServer so that this web application won't

        # accidentally let people access locations they shouldn't.

        # e.g. consider a smart server request for "get /etc/passwd" or

        # something.

        self.chroot_server = chroot.ChrootServer(backing_transport)

        self.chroot_server.start_server()

        self.backing_transport = get_transport(self.chroot_server.get_url())

        self.root_client_path = root_client_path

        # While the chroot server can technically be torn down at this point,

        # as all it does is remove the scheme registration from transport's

        # protocol dictionary, we don't *just in case* there are parts of

        # bzrlib that will invoke 'get_transport' on urls rather than cloning

        # around the existing transport.

        #self.chroot_server.stop_server()

    def __call__(self, environ, start_response):

        """WSGI application callable."""

        if environ['REQUEST_METHOD'] != 'POST':

            start_response('405 Method not allowed', [('Allow', 'POST')])

            return []

        relpath = environ['bzrlib.relpath']

        if not relpath.startswith('/'):

            relpath = '/' + relpath

        if not relpath.endswith('/'):

            relpath += '/'

        # Compare the HTTP path (relpath) and root_client_path, and calculate

        # new relpath and root_client_path accordingly, to be used to build the

        # request.

        if relpath.startswith(self.root_client_path):

            # The relpath traverses all of the mandatory root client path.

            # Remove the root_client_path from the relpath, and set

            # adjusted_tcp to None to tell the request handler that no further

            # path translation is required.

            adjusted_rcp = None

            adjusted_relpath = relpath[len(self.root_client_path):]

        elif self.root_client_path.startswith(relpath):

            # The relpath traverses some of the mandatory root client path.

            # Subtract the relpath from the root_client_path, and set the

            # relpath to '.'.

            adjusted_rcp = '/' + self.root_client_path[len(relpath):]

            adjusted_relpath = '.'

        else:

            adjusted_rcp = self.root_client_path

            adjusted_relpath = relpath

        if adjusted_relpath.startswith('/'):

            adjusted_relpath = adjusted_relpath[1:]

        if adjusted_relpath.startswith('/'):

            raise AssertionError(adjusted_relpath)

        transport = self.backing_transport.clone(adjusted_relpath)

        out_buffer = StringIO()

        request_data_length = int(environ['CONTENT_LENGTH'])

        request_data_bytes = environ['wsgi.input'].read(request_data_length)

        smart_protocol_request = self.make_request(

            transport, out_buffer.write, request_data_bytes, adjusted_rcp)

        if smart_protocol_request.next_read_size() != 0:

            # The request appears to be incomplete, or perhaps it's just a

            # newer version we don't understand.  Regardless, all we can do

            # is return an error response in the format of our version of the

            # protocol.

            response_data = 'error\x01incomplete request\n'

        else:

            response_data = out_buffer.getvalue()

        headers = [('Content-type', 'application/octet-stream')]

        headers.append(("Content-Length", str(len(response_data))))

        start_response('200 OK', headers)

        return [response_data]

    def make_request(self, transport, write_func, request_bytes, rcp):

        protocol_factory, unused_bytes = medium._get_protocol_factory_for_bytes(

            request_bytes)

        server_protocol = protocol_factory(

            transport, write_func, rcp, self.backing_transport)

        server_protocol.accept_bytes(unused_bytes)

        return server_protocol