~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2006, 2007 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

"""Basic server-side logic for dealing with requests.

**XXX**:

The class names are a little confusing: the protocol will instantiate a

SmartServerRequestHandler, whose dispatch_command method creates an instance of

a SmartServerRequest subclass.

The request_handlers registry tracks SmartServerRequest classes (rather than

SmartServerRequestHandler).

"""

import tempfile

from bzrlib import (

    bzrdir,

    errors,

    registry,

    revision,

    urlutils,

    )

from bzrlib.lazy_import import lazy_import

lazy_import(globals(), """

from bzrlib.bundle import serializer

""")

class SmartServerRequest(object):

    """Base class for request handlers.

    To define a new request, subclass this class and override the `do` method

    (and if appropriate, `do_body` as well).  Request implementors should take

    care to call `translate_client_path` and `transport_from_client_path` as

    appropriate when dealing with paths received from the client.

    """

    # XXX: rename this class to BaseSmartServerRequestHandler ?  A request

    # *handler* is a different concept to the request.

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

        """Constructor.

        :param backing_transport: the base transport to be used when performing

            this request.

        :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.  Clients will not be able to refer to paths above

            this root.  If root_client_path is None, then no translation will

            be performed on client paths.  Default is '/'.

        """

        self._backing_transport = backing_transport

        if root_client_path is not None:

            if not root_client_path.startswith('/'):

                root_client_path = '/' + root_client_path

            if not root_client_path.endswith('/'):

                root_client_path += '/'

        self._root_client_path = root_client_path

        self._body_chunks = []

    def _check_enabled(self):

        """Raises DisabledMethod if this method is disabled."""

        pass

    def do(self, *args):

        """Mandatory extension point for SmartServerRequest subclasses.

        Subclasses must implement this.

        This should return a SmartServerResponse if this command expects to

        receive no body.

        """

        raise NotImplementedError(self.do)

    def execute(self, *args):

        """Public entry point to execute this request.

        It will return a SmartServerResponse if the command does not expect a

        body.

        :param *args: the arguments of the request.

        """

        self._check_enabled()

        return self.do(*args)

    def do_body(self, body_bytes):

        """Called if the client sends a body with the request.

        The do() method is still called, and must have returned None.

        Must return a SmartServerResponse.

        """

        if body_bytes != '':

            raise errors.SmartProtocolError('Request does not expect a body')

    def do_chunk(self, chunk_bytes):

        """Called with each body chunk if the request has a streamed body.

        The do() method is still called, and must have returned None.

        """

        self._body_chunks.append(chunk_bytes)

    def do_end(self):

        """Called when the end of the request has been received."""

        body_bytes = ''.join(self._body_chunks)

        self._body_chunks = None

        return self.do_body(body_bytes)

    def translate_client_path(self, client_path):

        """Translate a path received from a network client into a local

        relpath.

        All paths received from the client *must* be translated.

        :param client_path: the path from the client.

        :returns: a relpath that may be used with self._backing_transport

            (unlike the untranslated client_path, which must not be used with

            the backing transport).

        """

        if self._root_client_path is None:

            # no translation necessary!

            return client_path

        if not client_path.startswith('/'):

            client_path = '/' + client_path

        if client_path.startswith(self._root_client_path):

            path = client_path[len(self._root_client_path):]

            relpath = urlutils.joinpath('/', path)

            if not relpath.startswith('/'):

                raise ValueError(relpath)

            return '.' + relpath

        else:

            raise errors.PathNotChild(client_path, self._root_client_path)

    def transport_from_client_path(self, client_path):

        """Get a backing transport corresponding to the location referred to by

        a network client.

        :seealso: translate_client_path

        :returns: a transport cloned from self._backing_transport

        """

        relpath = self.translate_client_path(client_path)

        return self._backing_transport.clone(relpath)

class SmartServerResponse(object):

    """A response to a client request.

    This base class should not be used. Instead use

    SuccessfulSmartServerResponse and FailedSmartServerResponse as appropriate.

    """

    def __init__(self, args, body=None, body_stream=None):

        """Constructor.

        :param args: tuple of response arguments.

        :param body: string of a response body.

        :param body_stream: iterable of bytestrings to be streamed to the

            client.

        """

        self.args = args

        if body is not None and body_stream is not None:

            raise errors.BzrError(

                "'body' and 'body_stream' are mutually exclusive.")

        self.body = body

        self.body_stream = body_stream

    def __eq__(self, other):

        if other is None:

            return False

        return (other.args == self.args and

                other.body == self.body and

                other.body_stream is self.body_stream)

    def __repr__(self):

        return "<%s args=%r body=%r>" % (self.__class__.__name__,

            self.args, self.body)

class FailedSmartServerResponse(SmartServerResponse):

    """A SmartServerResponse for a request which failed."""

    def is_successful(self):

        """FailedSmartServerResponse are not successful."""

        return False

class SuccessfulSmartServerResponse(SmartServerResponse):

    """A SmartServerResponse for a successfully completed request."""

    def is_successful(self):

        """SuccessfulSmartServerResponse are successful."""

        return True

class SmartServerRequestHandler(object):

    """Protocol logic for smart server.

    This doesn't handle serialization at all, it just processes requests and

    creates responses.

    """

    # IMPORTANT FOR IMPLEMENTORS: It is important that SmartServerRequestHandler

    # not contain encoding or decoding logic to allow the wire protocol to vary

    # from the object protocol: we will want to tweak the wire protocol separate

    # from the object model, and ideally we will be able to do that without

    # having a SmartServerRequestHandler subclass for each wire protocol, rather

    # just a Protocol subclass.

    # TODO: Better way of representing the body for commands that take it,

    # and allow it to be streamed into the server.

    def __init__(self, backing_transport, commands, root_client_path):

        """Constructor.

        :param backing_transport: a Transport to handle requests for.

        :param commands: a registry mapping command names to SmartServerRequest

            subclasses. e.g. bzrlib.transport.smart.vfs.vfs_commands.

        """

        self._backing_transport = backing_transport

        self._root_client_path = root_client_path

        self._commands = commands

        self.response = None

        self.finished_reading = False

        self._command = None

    def accept_body(self, bytes):

        """Accept body data."""

        self._run_handler_code(self._command.do_chunk, (bytes,), {})

    def end_of_body(self):

        """No more body data will be received."""

        self._run_handler_code(self._command.do_end, (), {})

        # cannot read after this.

        self.finished_reading = True

    def dispatch_command(self, cmd, args):

        """Deprecated compatibility method.""" # XXX XXX

        try:

            command = self._commands.get(cmd)

        except LookupError:

            raise errors.UnknownSmartMethod(cmd)

        self._command = command(self._backing_transport, self._root_client_path)

        self._run_handler_code(self._command.execute, args, {})

    def _run_handler_code(self, callable, args, kwargs):

        """Run some handler specific code 'callable'.

        If a result is returned, it is considered to be the commands response,

        and finished_reading is set true, and its assigned to self.response.

        Any exceptions caught are translated and a response object created

        from them.

        """

        result = self._call_converting_errors(callable, args, kwargs)

        if result is not None:

            self.response = result

            self.finished_reading = True

    def _call_converting_errors(self, callable, args, kwargs):

        """Call callable converting errors to Response objects."""

        # XXX: most of this error conversion is VFS-related, and thus ought to

        # be in SmartServerVFSRequestHandler somewhere.

        try:

            return callable(*args, **kwargs)

        except errors.NoSuchFile, e:

            return FailedSmartServerResponse(('NoSuchFile', e.path))

        except errors.FileExists, e:

            return FailedSmartServerResponse(('FileExists', e.path))

        except errors.DirectoryNotEmpty, e:

            return FailedSmartServerResponse(('DirectoryNotEmpty', e.path))

        except errors.ShortReadvError, e:

            return FailedSmartServerResponse(('ShortReadvError',

                e.path, str(e.offset), str(e.length), str(e.actual)))

        except errors.UnstackableRepositoryFormat, e:

            return FailedSmartServerResponse(('UnstackableRepositoryFormat',

                str(e.format), e.url))

        except errors.UnstackableBranchFormat, e:

            return FailedSmartServerResponse(('UnstackableBranchFormat',

                str(e.format), e.url))

        except errors.NotStacked, e:

            return FailedSmartServerResponse(('NotStacked',))

        except UnicodeError, e:

            # If it is a DecodeError, than most likely we are starting

            # with a plain string

            str_or_unicode = e.object

            if isinstance(str_or_unicode, unicode):

                # XXX: UTF-8 might have \x01 (our protocol v1 and v2 seperator

                # byte) in it, so this encoding could cause broken responses.

                # Newer clients use protocol v3, so will be fine.

                val = 'u:' + str_or_unicode.encode('utf-8')

            else:

                val = 's:' + str_or_unicode.encode('base64')

            # This handles UnicodeEncodeError or UnicodeDecodeError

            return FailedSmartServerResponse((e.__class__.__name__,

                    e.encoding, val, str(e.start), str(e.end), e.reason))

        except errors.TransportNotPossible, e:

            if e.msg == "readonly transport":

                return FailedSmartServerResponse(('ReadOnlyError', ))

            else:

                raise

        except errors.ReadError, e:

            # cannot read the file

            return FailedSmartServerResponse(('ReadError', e.path))

        except errors.PermissionDenied, e:

            return FailedSmartServerResponse(

                ('PermissionDenied', e.path, e.extra))

    def headers_received(self, headers):

        # Just a no-op at the moment.

        pass

    def args_received(self, args):

        cmd = args[0]

        args = args[1:]

        try:

            command = self._commands.get(cmd)

        except LookupError:

            raise errors.UnknownSmartMethod(cmd)

        self._command = command(self._backing_transport)

        self._run_handler_code(self._command.execute, args, {})

    def end_received(self):

        self._run_handler_code(self._command.do_end, (), {})

    def post_body_error_received(self, error_args):

        # Just a no-op at the moment.

        pass

class HelloRequest(SmartServerRequest):

    """Answer a version request with the highest protocol version this server

    supports.

    """

    def do(self):

        return SuccessfulSmartServerResponse(('ok', '2'))

class GetBundleRequest(SmartServerRequest):

    """Get a bundle of from the null revision to the specified revision."""

    def do(self, path, revision_id):

        # open transport relative to our base

        t = self.transport_from_client_path(path)

        control, extra_path = bzrdir.BzrDir.open_containing_from_transport(t)

        repo = control.open_repository()

        tmpf = tempfile.TemporaryFile()

        base_revision = revision.NULL_REVISION

        serializer.write_bundle(repo, revision_id, base_revision, tmpf)

        tmpf.seek(0)

        return SuccessfulSmartServerResponse((), tmpf.read())

class SmartServerIsReadonly(SmartServerRequest):

    # XXX: this request method belongs somewhere else.

    def do(self):

        if self._backing_transport.is_readonly():

            answer = 'yes'

        else:

            answer = 'no'

        return SuccessfulSmartServerResponse((answer,))

request_handlers = registry.Registry()

request_handlers.register_lazy(

    'append', 'bzrlib.smart.vfs', 'AppendRequest')

request_handlers.register_lazy(

    'Branch.get_config_file', 'bzrlib.smart.branch', 'SmartServerBranchGetConfigFile')

request_handlers.register_lazy(

    'Branch.get_stacked_on_url', 'bzrlib.smart.branch', 'SmartServerBranchRequestGetStackedOnURL')

request_handlers.register_lazy(

    'Branch.last_revision_info', 'bzrlib.smart.branch', 'SmartServerBranchRequestLastRevisionInfo')

request_handlers.register_lazy(

    'Branch.lock_write', 'bzrlib.smart.branch', 'SmartServerBranchRequestLockWrite')

request_handlers.register_lazy(

    'Branch.revision_history', 'bzrlib.smart.branch', 'SmartServerRequestRevisionHistory')

request_handlers.register_lazy(

    'Branch.set_last_revision', 'bzrlib.smart.branch', 'SmartServerBranchRequestSetLastRevision')

request_handlers.register_lazy(

    'Branch.set_last_revision_info', 'bzrlib.smart.branch',

    'SmartServerBranchRequestSetLastRevisionInfo')

request_handlers.register_lazy(

    'Branch.set_last_revision_ex', 'bzrlib.smart.branch',

    'SmartServerBranchRequestSetLastRevisionEx')

request_handlers.register_lazy(

    'Branch.unlock', 'bzrlib.smart.branch', 'SmartServerBranchRequestUnlock')

request_handlers.register_lazy(

    'BzrDir.create_branch', 'bzrlib.smart.bzrdir', 'SmartServerRequestCreateBranch')

request_handlers.register_lazy(

    'BzrDir.create_repository', 'bzrlib.smart.bzrdir', 'SmartServerRequestCreateRepository')

request_handlers.register_lazy(

    'BzrDir.find_repository', 'bzrlib.smart.bzrdir', 'SmartServerRequestFindRepositoryV1')

request_handlers.register_lazy(

    'BzrDir.find_repositoryV2', 'bzrlib.smart.bzrdir', 'SmartServerRequestFindRepositoryV2')

request_handlers.register_lazy(

    'BzrDirFormat.initialize', 'bzrlib.smart.bzrdir', 'SmartServerRequestInitializeBzrDir')

request_handlers.register_lazy(

    'BzrDir.open_branch', 'bzrlib.smart.bzrdir', 'SmartServerRequestOpenBranch')

request_handlers.register_lazy(

    'delete', 'bzrlib.smart.vfs', 'DeleteRequest')

request_handlers.register_lazy(

    'get', 'bzrlib.smart.vfs', 'GetRequest')

request_handlers.register_lazy(

    'get_bundle', 'bzrlib.smart.request', 'GetBundleRequest')

request_handlers.register_lazy(

    'has', 'bzrlib.smart.vfs', 'HasRequest')

request_handlers.register_lazy(

    'hello', 'bzrlib.smart.request', 'HelloRequest')

request_handlers.register_lazy(

    'iter_files_recursive', 'bzrlib.smart.vfs', 'IterFilesRecursiveRequest')

request_handlers.register_lazy(

    'list_dir', 'bzrlib.smart.vfs', 'ListDirRequest')

request_handlers.register_lazy(

    'mkdir', 'bzrlib.smart.vfs', 'MkdirRequest')

request_handlers.register_lazy(

    'move', 'bzrlib.smart.vfs', 'MoveRequest')

request_handlers.register_lazy(

    'put', 'bzrlib.smart.vfs', 'PutRequest')

request_handlers.register_lazy(

    'put_non_atomic', 'bzrlib.smart.vfs', 'PutNonAtomicRequest')

request_handlers.register_lazy(

    'readv', 'bzrlib.smart.vfs', 'ReadvRequest')

request_handlers.register_lazy(

    'rename', 'bzrlib.smart.vfs', 'RenameRequest')

request_handlers.register_lazy(

    'PackRepository.autopack', 'bzrlib.smart.packrepository',

    'SmartServerPackRepositoryAutopack')

request_handlers.register_lazy('Repository.gather_stats',

                               'bzrlib.smart.repository',

                               'SmartServerRepositoryGatherStats')

request_handlers.register_lazy('Repository.get_parent_map',

                               'bzrlib.smart.repository',

                               'SmartServerRepositoryGetParentMap')

request_handlers.register_lazy(

    'Repository.get_revision_graph', 'bzrlib.smart.repository', 'SmartServerRepositoryGetRevisionGraph')

request_handlers.register_lazy(

    'Repository.has_revision', 'bzrlib.smart.repository', 'SmartServerRequestHasRevision')

request_handlers.register_lazy(

    'Repository.insert_stream', 'bzrlib.smart.repository', 'SmartServerRepositoryInsertStream')

request_handlers.register_lazy(

    'Repository.is_shared', 'bzrlib.smart.repository', 'SmartServerRepositoryIsShared')

request_handlers.register_lazy(

    'Repository.lock_write', 'bzrlib.smart.repository', 'SmartServerRepositoryLockWrite')

request_handlers.register_lazy(

    'Repository.set_make_working_trees', 'bzrlib.smart.repository',

    'SmartServerRepositorySetMakeWorkingTrees')

request_handlers.register_lazy(

    'Repository.unlock', 'bzrlib.smart.repository', 'SmartServerRepositoryUnlock')

request_handlers.register_lazy(

    'Repository.tarball', 'bzrlib.smart.repository',

    'SmartServerRepositoryTarball')

request_handlers.register_lazy(

    'rmdir', 'bzrlib.smart.vfs', 'RmdirRequest')

request_handlers.register_lazy(

    'stat', 'bzrlib.smart.vfs', 'StatRequest')

request_handlers.register_lazy(

    'Transport.is_readonly', 'bzrlib.smart.request', 'SmartServerIsReadonly')

request_handlers.register_lazy(

    'BzrDir.open', 'bzrlib.smart.bzrdir', 'SmartServerRequestOpenBzrDir')