~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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 cStringIO import StringIO

from bzrlib.transport import chroot, get_transport, smart

from bzrlib.urlutils import local_path_to_url

def make_app(root, prefix, path_var, readonly=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)

    app = SmartWSGIApp(base_transport)

    app = RelpathSetter(app, prefix, 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):

        """Constructor.

        :param backing_transport: a transport.  Requests will be processed

            relative to this transport.

        """

        # Use a ChrootTransportDecorator 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.backing_transport = chroot.ChrootTransportDecorator(

            'chroot+' + backing_transport.base, _decorated=backing_transport)

    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']

        transport = self.backing_transport.clone(relpath)

        out_buffer = StringIO()

        smart_protocol_request = self.make_request(transport, out_buffer.write)

        request_data_length = int(environ['CONTENT_LENGTH'])

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

        smart_protocol_request.accept_bytes(request_data_bytes)

        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):

        return smart.SmartServerRequestProtocolOne(transport, write_func)