~bzr-pqm/bzr/bzr.dev

# Copyright (C) 2005 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

"""Implementation of Transport over http.

"""

from bzrlib.transport import Transport, register_transport

from bzrlib.errors import (TransportNotPossible, NoSuchFile, 

                           NonRelativePath, TransportError)

import os, errno

from cStringIO import StringIO

import urllib2

import urlparse

from bzrlib.errors import BzrError, BzrCheckError

from bzrlib.branch import Branch

from bzrlib.trace import mutter

def get_url(url):

    import urllib2

    mutter("get_url %s" % url)

    url_f = urllib2.urlopen(url)

    return url_f

class HttpTransportError(TransportError):

    pass

class HttpTransport(Transport):

    """This is the transport agent for http:// access.

    TODO: Implement pipelined versions of all of the *_multi() functions.

    """

    def __init__(self, base):

        """Set the base path where files will be stored."""

        assert base.startswith('http://') or base.startswith('https://')

        super(HttpTransport, self).__init__(base)

        # In the future we might actually connect to the remote host

        # rather than using get_url

        # self._connection = None

        (self._proto, self._host,

            self._path, self._parameters,

            self._query, self._fragment) = urlparse.urlparse(self.base)

    def should_cache(self):

        """Return True if the data pulled across should be cached locally.

        """

        return True

    def clone(self, offset=None):

        """Return a new HttpTransport with root at self.base + offset

        For now HttpTransport does not actually connect, so just return

        a new HttpTransport object.

        """

        if offset is None:

            return HttpTransport(self.base)

        else:

            return HttpTransport(self.abspath(offset))

    def abspath(self, relpath):

        """Return the full url to the given relative path.

        This can be supplied with a string or a list

        """

        assert isinstance(relpath, basestring)

        if isinstance(relpath, basestring):

            relpath_parts = relpath.split('/')

        else:

            # TODO: Don't call this with an array - no magic interfaces

            relpath_parts = relpath[:]

        if len(relpath_parts) > 1:

            if relpath_parts[0] == '':

                raise ValueError("path %r within branch %r seems to be absolute"

                                 % (relpath, self._path))

            if relpath_parts[-1] == '':

                raise ValueError("path %r within branch %r seems to be a directory"

                                 % (relpath, self._path))

        basepath = self._path.split('/')

        if len(basepath) > 0 and basepath[-1] == '':

            basepath = basepath[:-1]

        for p in relpath_parts:

            if p == '..':

                if len(basepath) == 0:

                    # In most filesystems, a request for the parent

                    # of root, just returns root.

                    continue

                basepath.pop()

            elif p == '.' or p == '':

                continue # No-op

            else:

                basepath.append(p)

        # Possibly, we could use urlparse.urljoin() here, but

        # I'm concerned about when it chooses to strip the last

        # portion of the path, and when it doesn't.

        path = '/'.join(basepath)

        return urlparse.urlunparse((self._proto,

                self._host, path, '', '', ''))

    def has(self, relpath):

        """Does the target location exist?

        TODO: HttpTransport.has() should use a HEAD request,

        not a full GET request.

        TODO: This should be changed so that we don't use

        urllib2 and get an exception, the code path would be

        cleaner if we just do an http HEAD request, and parse

        the return code.

        """

        try:

            f = get_url(self.abspath(relpath))

            # Without the read and then close()

            # we tend to have busy sockets.

            f.read()

            f.close()

            return True

        except urllib2.URLError, e:

            if e.code == 404:

                return False

            raise

        except IOError, e:

            if e.errno == errno.ENOENT:

                return False

            raise HttpTransportError(orig_error=e)

    def get(self, relpath, decode=False):

        """Get the file at the given relative path.

        :param relpath: The relative path to the file

        """

        try:

            return get_url(self.abspath(relpath))

        except urllib2.URLError, e:

            if getattr(e, 'code', None) == 404:

                raise NoSuchFile(msg = "Error retrieving %s: %s" 

                                 % (self.abspath(relpath), str(e)),

                                 orig_error=e)

            raise

        except (BzrError, IOError), e:

            raise NoSuchFile(msg = "Error retrieving %s: %s" 

                             % (self.abspath(relpath), str(e)),

                             orig_error=e)

    def put(self, relpath, f):

        """Copy the file-like or string object into the location.

        :param relpath: Location to put the contents, relative to base.

        :param f:       File-like or string object.

        """

        raise TransportNotPossible('http PUT not supported')

    def mkdir(self, relpath):

        """Create a directory at the given path."""

        raise TransportNotPossible('http does not support mkdir()')

    def append(self, relpath, f):

        """Append the text in the file-like object into the final

        location.

        """

        raise TransportNotPossible('http does not support append()')

    def copy(self, rel_from, rel_to):

        """Copy the item at rel_from to the location at rel_to"""

        raise TransportNotPossible('http does not support copy()')

    def copy_to(self, relpaths, other, pb=None):

        """Copy a set of entries from self into another Transport.

        :param relpaths: A list/generator of entries to be copied.

        TODO: if other is LocalTransport, is it possible to

              do better than put(get())?

        """

        # At this point HttpTransport might be able to check and see if

        # the remote location is the same, and rather than download, and

        # then upload, it could just issue a remote copy_this command.

        if isinstance(other, HttpTransport):

            raise TransportNotPossible('http cannot be the target of copy_to()')

        else:

            return super(HttpTransport, self).copy_to(relpaths, other, pb=pb)

    def move(self, rel_from, rel_to):

        """Move the item at rel_from to the location at rel_to"""

        raise TransportNotPossible('http does not support move()')

    def delete(self, relpath):

        """Delete the item at relpath"""

        raise TransportNotPossible('http does not support delete()')

    def listable(self):

        """See Transport.listable."""

        return False

    def stat(self, relpath):

        """Return the stat information for a file.

        """

        raise TransportNotPossible('http does not support stat()')

    def lock_read(self, relpath):

        """Lock the given file for shared (read) access.

        :return: A lock object, which should be passed to Transport.unlock()

        """

        # The old RemoteBranch ignore lock for reading, so we will

        # continue that tradition and return a bogus lock object.

        class BogusLock(object):

            def __init__(self, path):

                self.path = path

            def unlock(self):

                pass

        return BogusLock(relpath)

    def lock_write(self, relpath):

        """Lock the given file for exclusive (write) access.

        WARNING: many transports do not support this, so trying avoid using it

        :return: A lock object, which should be passed to Transport.unlock()

        """

        raise TransportNotPossible('http does not support lock_write()')