wireprotoserver: rename abstractserverproto and improve docstring
The docstring isn't completely accurate for the current state
of the world. But it does describe the direction future patches
will be taking things.
Differential Revision: https://phab.mercurial-scm.org/D2065
# Copyright 21 May 2005 - (c) 2005 Jake Edge <jake@edge2.net>
# Copyright 2005-2007 Matt Mackall <mpm@selenic.com>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
from __future__ import absolute_import
import abc
import cgi
import struct
import sys
from .i18n import _
from . import (
encoding,
error,
hook,
pycompat,
util,
wireproto,
)
stringio = util.stringio
urlerr = util.urlerr
urlreq = util.urlreq
HTTP_OK = 200
HGTYPE = 'application/mercurial-0.1'
HGTYPE2 = 'application/mercurial-0.2'
HGERRTYPE = 'application/hg-error'
# Names of the SSH protocol implementations.
SSHV1 = 'ssh-v1'
# This is advertised over the wire. Incremental the counter at the end
# to reflect BC breakages.
SSHV2 = 'exp-ssh-v2-0001'
class baseprotocolhandler(object):
"""Abstract base class for wire protocol handlers.
A wire protocol handler serves as an interface between protocol command
handlers and the wire protocol transport layer. Protocol handlers provide
methods to read command arguments, redirect stdio for the duration of
the request, handle response types, etc.
"""
__metaclass__ = abc.ABCMeta
@abc.abstractproperty
def name(self):
"""The name of the protocol implementation.
Used for uniquely identifying the transport type.
"""
@abc.abstractmethod
def getargs(self, args):
"""return the value for arguments in <args>
returns a list of values (same order as <args>)"""
@abc.abstractmethod
def getfile(self, fp):
"""write the whole content of a file into a file like object
The file is in the form::
(<chunk-size>\n<chunk>)+0\n
chunk size is the ascii version of the int.
"""
@abc.abstractmethod
def redirect(self):
"""may setup interception for stdout and stderr
See also the `restore` method."""
# If the `redirect` function does install interception, the `restore`
# function MUST be defined. If interception is not used, this function
# MUST NOT be defined.
#
# left commented here on purpose
#
#def restore(self):
# """reinstall previous stdout and stderr and return intercepted stdout
# """
# raise NotImplementedError()
def decodevaluefromheaders(req, headerprefix):
"""Decode a long value from multiple HTTP request headers.
Returns the value as a bytes, not a str.
"""
chunks = []
i = 1
prefix = headerprefix.upper().replace(r'-', r'_')
while True:
v = req.env.get(r'HTTP_%s_%d' % (prefix, i))
if v is None:
break
chunks.append(pycompat.bytesurl(v))
i += 1
return ''.join(chunks)
class webproto(baseprotocolhandler):
def __init__(self, req, ui):
self._req = req
self._ui = ui
@property
def name(self):
return 'http'
def getargs(self, args):
knownargs = self._args()
data = {}
keys = args.split()
for k in keys:
if k == '*':
star = {}
for key in knownargs.keys():
if key != 'cmd' and key not in keys:
star[key] = knownargs[key][0]
data['*'] = star
else:
data[k] = knownargs[k][0]
return [data[k] for k in keys]
def _args(self):
args = util.rapply(pycompat.bytesurl, self._req.form.copy())
postlen = int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))
if postlen:
args.update(cgi.parse_qs(
self._req.read(postlen), keep_blank_values=True))
return args
argvalue = decodevaluefromheaders(self._req, r'X-HgArg')
args.update(cgi.parse_qs(argvalue, keep_blank_values=True))
return args
def getfile(self, fp):
length = int(self._req.env[r'CONTENT_LENGTH'])
# If httppostargs is used, we need to read Content-Length
# minus the amount that was consumed by args.
length -= int(self._req.env.get(r'HTTP_X_HGARGS_POST', 0))
for s in util.filechunkiter(self._req, limit=length):
fp.write(s)
def redirect(self):
self._oldio = self._ui.fout, self._ui.ferr
self._ui.ferr = self._ui.fout = stringio()
def restore(self):
val = self._ui.fout.getvalue()
self._ui.ferr, self._ui.fout = self._oldio
return val
def _client(self):
return 'remote:%s:%s:%s' % (
self._req.env.get('wsgi.url_scheme') or 'http',
urlreq.quote(self._req.env.get('REMOTE_HOST', '')),
urlreq.quote(self._req.env.get('REMOTE_USER', '')))
def responsetype(self, prefer_uncompressed):
"""Determine the appropriate response type and compression settings.
Returns a tuple of (mediatype, compengine, engineopts).
"""
# Determine the response media type and compression engine based
# on the request parameters.
protocaps = decodevaluefromheaders(self._req, r'X-HgProto').split(' ')
if '0.2' in protocaps:
# All clients are expected to support uncompressed data.
if prefer_uncompressed:
return HGTYPE2, util._noopengine(), {}
# Default as defined by wire protocol spec.
compformats = ['zlib', 'none']
for cap in protocaps:
if cap.startswith('comp='):
compformats = cap[5:].split(',')
break
# Now find an agreed upon compression format.
for engine in wireproto.supportedcompengines(self._ui, self,
util.SERVERROLE):
if engine.wireprotosupport().name in compformats:
opts = {}
level = self._ui.configint('server',
'%slevel' % engine.name())
if level is not None:
opts['level'] = level
return HGTYPE2, engine, opts
# No mutually supported compression format. Fall back to the
# legacy protocol.
# Don't allow untrusted settings because disabling compression or
# setting a very high compression level could lead to flooding
# the server's network or CPU.
opts = {'level': self._ui.configint('server', 'zliblevel')}
return HGTYPE, util.compengines['zlib'], opts
def iscmd(cmd):
return cmd in wireproto.commands
def parsehttprequest(repo, req, query):
"""Parse the HTTP request for a wire protocol request.
If the current request appears to be a wire protocol request, this
function returns a dict with details about that request, including
an ``abstractprotocolserver`` instance suitable for handling the
request. Otherwise, ``None`` is returned.
``req`` is a ``wsgirequest`` instance.
"""
# HTTP version 1 wire protocol requests are denoted by a "cmd" query
# string parameter. If it isn't present, this isn't a wire protocol
# request.
if r'cmd' not in req.form:
return None
cmd = pycompat.sysbytes(req.form[r'cmd'][0])
# The "cmd" request parameter is used by both the wire protocol and hgweb.
# While not all wire protocol commands are available for all transports,
# if we see a "cmd" value that resembles a known wire protocol command, we
# route it to a protocol handler. This is better than routing possible
# wire protocol requests to hgweb because it prevents hgweb from using
# known wire protocol commands and it is less confusing for machine
# clients.
if cmd not in wireproto.commands:
return None
proto = webproto(req, repo.ui)
return {
'cmd': cmd,
'proto': proto,
'dispatch': lambda: _callhttp(repo, req, proto, cmd),
'handleerror': lambda ex: _handlehttperror(ex, req, cmd),
}
def _callhttp(repo, req, proto, cmd):
def genversion2(gen, engine, engineopts):
# application/mercurial-0.2 always sends a payload header
# identifying the compression engine.
name = engine.wireprotosupport().name
assert 0 < len(name) < 256
yield struct.pack('B', len(name))
yield name
for chunk in gen:
yield chunk
rsp = wireproto.dispatch(repo, proto, cmd)
if not wireproto.commands.commandavailable(cmd, proto):
req.respond(HTTP_OK, HGERRTYPE,
body=_('requested wire protocol command is not available '
'over HTTP'))
return []
if isinstance(rsp, bytes):
req.respond(HTTP_OK, HGTYPE, body=rsp)
return []
elif isinstance(rsp, wireproto.streamres_legacy):
gen = rsp.gen
req.respond(HTTP_OK, HGTYPE)
return gen
elif isinstance(rsp, wireproto.streamres):
gen = rsp.gen
# This code for compression should not be streamres specific. It
# is here because we only compress streamres at the moment.
mediatype, engine, engineopts = proto.responsetype(
rsp.prefer_uncompressed)
gen = engine.compressstream(gen, engineopts)
if mediatype == HGTYPE2:
gen = genversion2(gen, engine, engineopts)
req.respond(HTTP_OK, mediatype)
return gen
elif isinstance(rsp, wireproto.pushres):
val = proto.restore()
rsp = '%d\n%s' % (rsp.res, val)
req.respond(HTTP_OK, HGTYPE, body=rsp)
return []
elif isinstance(rsp, wireproto.pusherr):
# This is the httplib workaround documented in _handlehttperror().
req.drain()
proto.restore()
rsp = '0\n%s\n' % rsp.res
req.respond(HTTP_OK, HGTYPE, body=rsp)
return []
elif isinstance(rsp, wireproto.ooberror):
rsp = rsp.message
req.respond(HTTP_OK, HGERRTYPE, body=rsp)
return []
raise error.ProgrammingError('hgweb.protocol internal failure', rsp)
def _handlehttperror(e, req, cmd):
"""Called when an ErrorResponse is raised during HTTP request processing."""
# Clients using Python's httplib are stateful: the HTTP client
# won't process an HTTP response until all request data is
# sent to the server. The intent of this code is to ensure
# we always read HTTP request data from the client, thus
# ensuring httplib transitions to a state that allows it to read
# the HTTP response. In other words, it helps prevent deadlocks
# on clients using httplib.
if (req.env[r'REQUEST_METHOD'] == r'POST' and
# But not if Expect: 100-continue is being used.
(req.env.get('HTTP_EXPECT',
'').lower() != '100-continue') or
# Or the non-httplib HTTP library is being advertised by
# the client.
req.env.get('X-HgHttp2', '')):
req.drain()
else:
req.headers.append((r'Connection', r'Close'))
# TODO This response body assumes the failed command was
# "unbundle." That assumption is not always valid.
req.respond(e, HGTYPE, body='0\n%s\n' % e)
return ''
class sshserver(baseprotocolhandler):
def __init__(self, ui, repo):
self._ui = ui
self._repo = repo
self._fin = ui.fin
self._fout = ui.fout
hook.redirect(True)
ui.fout = repo.ui.fout = ui.ferr
# Prevent insertion/deletion of CRs
util.setbinary(self._fin)
util.setbinary(self._fout)
@property
def name(self):
return 'ssh'
def getargs(self, args):
data = {}
keys = args.split()
for n in xrange(len(keys)):
argline = self._fin.readline()[:-1]
arg, l = argline.split()
if arg not in keys:
raise error.Abort(_("unexpected parameter %r") % arg)
if arg == '*':
star = {}
for k in xrange(int(l)):
argline = self._fin.readline()[:-1]
arg, l = argline.split()
val = self._fin.read(int(l))
star[arg] = val
data['*'] = star
else:
val = self._fin.read(int(l))
data[arg] = val
return [data[k] for k in keys]
def getfile(self, fpout):
self._sendresponse('')
count = int(self._fin.readline())
while count:
fpout.write(self._fin.read(count))
count = int(self._fin.readline())
def redirect(self):
pass
def _sendresponse(self, v):
self._fout.write("%d\n" % len(v))
self._fout.write(v)
self._fout.flush()
def _sendstream(self, source):
write = self._fout.write
for chunk in source.gen:
write(chunk)
self._fout.flush()
def _sendpushresponse(self, rsp):
self._sendresponse('')
self._sendresponse(str(rsp.res))
def _sendpusherror(self, rsp):
self._sendresponse(rsp.res)
def _sendooberror(self, rsp):
self._ui.ferr.write('%s\n-\n' % rsp.message)
self._ui.ferr.flush()
self._fout.write('\n')
self._fout.flush()
def serve_forever(self):
while self.serve_one():
pass
sys.exit(0)
_handlers = {
str: _sendresponse,
wireproto.streamres: _sendstream,
wireproto.streamres_legacy: _sendstream,
wireproto.pushres: _sendpushresponse,
wireproto.pusherr: _sendpusherror,
wireproto.ooberror: _sendooberror,
}
def serve_one(self):
cmd = self._fin.readline()[:-1]
if cmd and wireproto.commands.commandavailable(cmd, self):
rsp = wireproto.dispatch(self._repo, self, cmd)
self._handlers[rsp.__class__](self, rsp)
elif cmd:
self._sendresponse("")
return cmd != ''
def _client(self):
client = encoding.environ.get('SSH_CLIENT', '').split(' ', 1)[0]
return 'remote:ssh:' + client