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# server.py -- Implementation of the server side git protocols
# Copryight (C) 2008 John Carr <john.carr@unrouted.co.uk>
#
# 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; version 2
# or (at your option) any later version of the License.
#
# 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.
"""Git smart network protocol server implementation."""
import SocketServer
import tempfile
from dulwich.protocol import (
Protocol,
ProtocolFile,
TCP_GIT_PORT,
extract_capabilities,
)
from dulwich.repo import (
Repo,
)
from dulwich.pack import (
write_pack_data,
)
class Backend(object):
def get_refs(self):
"""
Get all the refs in the repository
:return: dict of name -> sha
"""
raise NotImplementedError
def apply_pack(self, refs, read):
""" Import a set of changes into a repository and update the refs
:param refs: list of tuple(name, sha)
:param read: callback to read from the incoming pack
"""
raise NotImplementedError
def fetch_objects(self, determine_wants, graph_walker, progress):
"""
Yield the objects required for a list of commits.
:param progress: is a callback to send progress messages to the client
"""
raise NotImplementedError
class GitBackend(Backend):
def __init__(self, gitdir=None):
self.gitdir = gitdir
if not self.gitdir:
self.gitdir = tempfile.mkdtemp()
Repo.create(self.gitdir)
self.repo = Repo(self.gitdir)
self.fetch_objects = self.repo.fetch_objects
self.get_refs = self.repo.get_refs
def apply_pack(self, refs, read):
fd, commit = self.repo.object_store.add_thin_pack()
fd.write(read())
fd.close()
commit()
for oldsha, sha, ref in refs:
if ref == "0" * 40:
self.repo.remove_ref(ref)
else:
self.repo.set_ref(ref, sha)
print "pack applied"
class Handler(object):
"""Smart protocol command handler base class."""
def __init__(self, backend, read, write):
self.backend = backend
self.proto = Protocol(read, write)
def capabilities(self):
return " ".join(self.default_capabilities())
class UploadPackHandler(Handler):
"""Protocol handler for uploading a pack to the server."""
def default_capabilities(self):
return ("multi_ack", "side-band-64k", "thin-pack", "ofs-delta")
def handle(self):
def determine_wants(heads):
keys = heads.keys()
if keys:
self.proto.write_pkt_line("%s %s\x00%s\n" % ( heads[keys[0]], keys[0], self.capabilities()))
for k in keys[1:]:
self.proto.write_pkt_line("%s %s\n" % (heads[k], k))
# i'm done..
self.proto.write("0000")
# Now client will either send "0000", meaning that it doesnt want to pull.
# or it will start sending want want want commands
want = self.proto.read_pkt_line()
if want == None:
return []
want, self.client_capabilities = extract_capabilities(want)
want_revs = []
while want and want[:4] == 'want':
want_revs.append(want[5:45])
want = self.proto.read_pkt_line()
return want_revs
progress = lambda x: self.proto.write_sideband(2, x)
write = lambda x: self.proto.write_sideband(1, x)
class ProtocolGraphWalker(object):
def __init__(self, proto):
self.proto = proto
self._last_sha = None
def ack(self, have_ref):
self.proto.write_pkt_line("ACK %s continue\n" % have_ref)
def next(self):
have = self.proto.read_pkt_line()
if have[:4] == 'have':
return have[5:45]
#if have[:4] == 'done':
# return None
if self._last_sha:
# Oddness: Git seems to resend the last ACK, without the "continue" statement
self.proto.write_pkt_line("ACK %s\n" % self._last_sha)
# The exchange finishes with a NAK
self.proto.write_pkt_line("NAK\n")
graph_walker = ProtocolGraphWalker(self.proto)
num_objects, objects_iter = self.backend.fetch_objects(determine_wants, graph_walker, progress)
# Do they want any objects?
if num_objects == 0:
return
progress("dul-daemon says what\n")
progress("counting objects: %d, done.\n" % num_objects)
write_pack_data(ProtocolFile(None, write), objects_iter, num_objects)
progress("how was that, then?\n")
# we are done
self.proto.write("0000")
class ReceivePackHandler(Handler):
"""Protocol handler for downloading a pack to the client."""
def default_capabilities(self):
return ("report-status", "delete-refs")
def handle(self):
refs = self.backend.get_refs().items()
if refs:
self.proto.write_pkt_line("%s %s\x00%s\n" % (refs[0][1], refs[0][0], self.capabilities()))
for i in range(1, len(refs)):
ref = refs[i]
self.proto.write_pkt_line("%s %s\n" % (ref[1], ref[0]))
else:
self.proto.write_pkt_line("0000000000000000000000000000000000000000 capabilities^{} %s" % self.capabilities())
self.proto.write("0000")
client_refs = []
ref = self.proto.read_pkt_line()
# if ref is none then client doesnt want to send us anything..
if ref is None:
return
ref, client_capabilities = extract_capabilities(ref)
# client will now send us a list of (oldsha, newsha, ref)
while ref:
client_refs.append(ref.split())
ref = self.proto.read_pkt_line()
# backend can now deal with this refs and read a pack using self.read
self.backend.apply_pack(client_refs, self.proto.read)
# when we have read all the pack from the client, it assumes
# everything worked OK.
# there is NO ack from the server before it reports victory.
class TCPGitRequestHandler(SocketServer.StreamRequestHandler):
def handle(self):
proto = Protocol(self.rfile.read, self.wfile.write)
command, args = proto.read_cmd()
# switch case to handle the specific git command
if command == 'git-upload-pack':
cls = UploadPackHandler
elif command == 'git-receive-pack':
cls = ReceivePackHandler
else:
return
h = cls(self.server.backend, self.rfile.read, self.wfile.write)
h.handle()
class TCPGitServer(SocketServer.TCPServer):
allow_reuse_address = True
serve = SocketServer.TCPServer.serve_forever
def __init__(self, backend, listen_addr, port=TCP_GIT_PORT):
self.backend = backend
SocketServer.TCPServer.__init__(self, (listen_addr, port), TCPGitRequestHandler)
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