httppeer: move error handling and response wrapping into sendrequest

This is common for all HTTP requests. It should be part of
sendrequest().

Differential Revision: https://phab.mercurial-scm.org/D3235

mercurial/httppeer.py

@@ -1,633 +1,635 b''
 # httppeer.py - HTTP repository proxy classes for mercurial
 #
 # Copyright 2005, 2006 Matt Mackall <[e-mail]>
 # Copyright 2006 Vadim Gelfer <[e-mail]>
 #
 # 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 errno
 import io
 import os
 import socket
 import struct
 import tempfile
 
 from .i18n import _
 from .thirdparty import (
     cbor,
 )
 from . import (
     bundle2,
     error,
     httpconnection,
     pycompat,
     statichttprepo,
     url as urlmod,
     util,
     wireproto,
     wireprotoframing,
     wireprotov2server,
 )
 
 httplib = util.httplib
 urlerr = util.urlerr
 urlreq = util.urlreq
 
 def encodevalueinheaders(value, header, limit):
     """Encode a string value into multiple HTTP headers.
 
     ``value`` will be encoded into 1 or more HTTP headers with the names
     ``header-<N>`` where ``<N>`` is an integer starting at 1. Each header
     name + value will be at most ``limit`` bytes long.
 
     Returns an iterable of 2-tuples consisting of header names and
     values as native strings.
     """
     # HTTP Headers are ASCII. Python 3 requires them to be unicodes,
     # not bytes. This function always takes bytes in as arguments.
     fmt = pycompat.strurl(header) + r'-%s'
     # Note: it is *NOT* a bug that the last bit here is a bytestring
     # and not a unicode: we're just getting the encoded length anyway,
     # and using an r-string to make it portable between Python 2 and 3
     # doesn't work because then the \r is a literal backslash-r
     # instead of a carriage return.
     valuelen = limit - len(fmt % r'000') - len(': \r\n')
     result = []
 
     n = 0
     for i in xrange(0, len(value), valuelen):
         n += 1
         result.append((fmt % str(n), pycompat.strurl(value[i:i + valuelen])))
 
     return result
 
 def _wraphttpresponse(resp):
     """Wrap an HTTPResponse with common error handlers.
 
     This ensures that any I/O from any consumer raises the appropriate
     error and messaging.
     """
     origread = resp.read
 
     class readerproxy(resp.__class__):
         def read(self, size=None):
             try:
                 return origread(size)
             except httplib.IncompleteRead as e:
                 # e.expected is an integer if length known or None otherwise.
                 if e.expected:
                     msg = _('HTTP request error (incomplete response; '
                             'expected %d bytes got %d)') % (e.expected,
                                                            len(e.partial))
                 else:
                     msg = _('HTTP request error (incomplete response)')
 
                 raise error.PeerTransportError(
                     msg,
                     hint=_('this may be an intermittent network failure; '
                            'if the error persists, consider contacting the '
                            'network or server operator'))
             except httplib.HTTPException as e:
                 raise error.PeerTransportError(
                     _('HTTP request error (%s)') % e,
                     hint=_('this may be an intermittent network failure; '
                            'if the error persists, consider contacting the '
                            'network or server operator'))
 
     resp.__class__ = readerproxy
 
 class _multifile(object):
     def __init__(self, *fileobjs):
         for f in fileobjs:
             if not util.safehasattr(f, 'length'):
                 raise ValueError(
                     '_multifile only supports file objects that '
                     'have a length but this one does not:', type(f), f)
         self._fileobjs = fileobjs
         self._index = 0
 
     @property
     def length(self):
         return sum(f.length for f in self._fileobjs)
 
     def read(self, amt=None):
         if amt <= 0:
             return ''.join(f.read() for f in self._fileobjs)
         parts = []
         while amt and self._index < len(self._fileobjs):
             parts.append(self._fileobjs[self._index].read(amt))
             got = len(parts[-1])
             if got < amt:
                 self._index += 1
             amt -= got
         return ''.join(parts)
 
     def seek(self, offset, whence=os.SEEK_SET):
         if whence != os.SEEK_SET:
             raise NotImplementedError(
                 '_multifile does not support anything other'
                 ' than os.SEEK_SET for whence on seek()')
         if offset != 0:
             raise NotImplementedError(
                 '_multifile only supports seeking to start, but that '
                 'could be fixed if you need it')
         for f in self._fileobjs:
             f.seek(0)
         self._index = 0
 
 def makev1commandrequest(ui, requestbuilder, caps, capablefn,
                          repobaseurl, cmd, args):
     """Make an HTTP request to run a command for a version 1 client.
 
     ``caps`` is a set of known server capabilities. The value may be
     None if capabilities are not yet known.
 
     ``capablefn`` is a function to evaluate a capability.
 
     ``cmd``, ``args``, and ``data`` define the command, its arguments, and
     raw data to pass to it.
     """
     if cmd == 'pushkey':
         args['data'] = ''
     data = args.pop('data', None)
     headers = args.pop('headers', {})
 
     ui.debug("sending %s command\n" % cmd)
     q = [('cmd', cmd)]
     headersize = 0
     varyheaders = []
     # Important: don't use self.capable() here or else you end up
     # with infinite recursion when trying to look up capabilities
     # for the first time.
     postargsok = caps is not None and 'httppostargs' in caps
 
     # Send arguments via POST.
     if postargsok and args:
         strargs = urlreq.urlencode(sorted(args.items()))
         if not data:
             data = strargs
         else:
             if isinstance(data, bytes):
                 i = io.BytesIO(data)
                 i.length = len(data)
                 data = i
             argsio = io.BytesIO(strargs)
             argsio.length = len(strargs)
             data = _multifile(argsio, data)
         headers[r'X-HgArgs-Post'] = len(strargs)
     elif args:
         # Calling self.capable() can infinite loop if we are calling
         # "capabilities". But that command should never accept wire
         # protocol arguments. So this should never happen.
         assert cmd != 'capabilities'
         httpheader = capablefn('httpheader')
         if httpheader:
             headersize = int(httpheader.split(',', 1)[0])
 
         # Send arguments via HTTP headers.
         if headersize > 0:
             # The headers can typically carry more data than the URL.
             encargs = urlreq.urlencode(sorted(args.items()))
             for header, value in encodevalueinheaders(encargs, 'X-HgArg',
                                                       headersize):
                 headers[header] = value
                 varyheaders.append(header)
         # Send arguments via query string (Mercurial <1.9).
         else:
             q += sorted(args.items())
 
     qs = '?%s' % urlreq.urlencode(q)
     cu = "%s%s" % (repobaseurl, qs)
     size = 0
     if util.safehasattr(data, 'length'):
         size = data.length
     elif data is not None:
         size = len(data)
     if data is not None and r'Content-Type' not in headers:
         headers[r'Content-Type'] = r'application/mercurial-0.1'
 
     # Tell the server we accept application/mercurial-0.2 and multiple
     # compression formats if the server is capable of emitting those
     # payloads.
     protoparams = {'partial-pull'}
 
     mediatypes = set()
     if caps is not None:
         mt = capablefn('httpmediatype')
         if mt:
             protoparams.add('0.1')
             mediatypes = set(mt.split(','))
 
     if '0.2tx' in mediatypes:
         protoparams.add('0.2')
 
     if '0.2tx' in mediatypes and capablefn('compression'):
         # We /could/ compare supported compression formats and prune
         # non-mutually supported or error if nothing is mutually supported.
         # For now, send the full list to the server and have it error.
         comps = [e.wireprotosupport().name for e in
                  util.compengines.supportedwireengines(util.CLIENTROLE)]
         protoparams.add('comp=%s' % ','.join(comps))
 
     if protoparams:
         protoheaders = encodevalueinheaders(' '.join(sorted(protoparams)),
                                             'X-HgProto',
                                             headersize or 1024)
         for header, value in protoheaders:
             headers[header] = value
             varyheaders.append(header)
 
     if varyheaders:
         headers[r'Vary'] = r','.join(varyheaders)
 
     req = requestbuilder(pycompat.strurl(cu), data, headers)
 
     if data is not None:
         ui.debug("sending %d bytes\n" % size)
         req.add_unredirected_header(r'Content-Length', r'%d' % size)
 
     return req, cu, qs
 
 def sendrequest(ui, opener, req):
     """Send a prepared HTTP request.
 
     Returns the response object.
     """
     if (ui.debugflag
         and ui.configbool('devel', 'debug.peer-request')):
         dbg = ui.debug
         line = 'devel-peer-request: %s\n'
         dbg(line % '%s %s' % (req.get_method(), req.get_full_url()))
         hgargssize = None
 
         for header, value in sorted(req.header_items()):
             if header.startswith('X-hgarg-'):
                 if hgargssize is None:
                     hgargssize = 0
                 hgargssize += len(value)
             else:
                 dbg(line % '  %s %s' % (header, value))
 
         if hgargssize is not None:
             dbg(line % '  %d bytes of commands arguments in headers'
                 % hgargssize)
 
         if req.has_data():
             data = req.get_data()
             length = getattr(data, 'length', None)
             if length is None:
                 length = len(data)
             dbg(line % '  %d bytes of data' % length)
 
         start = util.timer()
 
+    try:
     res = opener.open(req)
+    except urlerr.httperror as inst:
+        if inst.code == 401:
+            raise error.Abort(_('authorization failed'))
+        raise
+    except httplib.HTTPException as inst:
+        ui.debug('http error requesting %s\n' %
+                 util.hidepassword(req.get_full_url()))
+        ui.traceback()
+        raise IOError(None, inst)
+    finally:
     if ui.configbool('devel', 'debug.peer-request'):
         dbg(line % '  finished in %.4f seconds (%s)'
             % (util.timer() - start, res.code))
 
+    # Insert error handlers for common I/O failures.
+    _wraphttpresponse(res)
+
     return res
 
 class httppeer(wireproto.wirepeer):
     def __init__(self, ui, path, url, opener, requestbuilder):
         self.ui = ui
         self._path = path
         self._url = url
         self._caps = None
         self._urlopener = opener
         self._requestbuilder = requestbuilder
 
     def __del__(self):
         for h in self._urlopener.handlers:
             h.close()
             getattr(h, "close_all", lambda: None)()
 
     # Begin of ipeerconnection interface.
 
     def url(self):
         return self._path
 
     def local(self):
         return None
 
     def peer(self):
         return self
 
     def canpush(self):
         return True
 
     def close(self):
         pass
 
     # End of ipeerconnection interface.
 
     # Begin of ipeercommands interface.
 
     def capabilities(self):
         # self._fetchcaps() should have been called as part of peer
         # handshake. So self._caps should always be set.
         assert self._caps is not None
         return self._caps
 
     # End of ipeercommands interface.
 
     # look up capabilities only when needed
 
     def _fetchcaps(self):
         self._caps = set(self._call('capabilities').split())
 
     def _callstream(self, cmd, _compressible=False, **args):
         args = pycompat.byteskwargs(args)
 
         req, cu, qs = makev1commandrequest(self.ui, self._requestbuilder,
                                            self._caps, self.capable,
                                            self._url, cmd, args)
 
-        try:
             resp = sendrequest(self.ui, self._urlopener, req)
-        except urlerr.httperror as inst:
-            if inst.code == 401:
-                raise error.Abort(_('authorization failed'))
-            raise
-        except httplib.HTTPException as inst:
-            self.ui.debug('http error while sending %s command\n' % cmd)
-            self.ui.traceback()
-            raise IOError(None, inst)
-
-        # Insert error handlers for common I/O failures.
-        _wraphttpresponse(resp)
 
         # record the url we got redirected to
         resp_url = pycompat.bytesurl(resp.geturl())
         if resp_url.endswith(qs):
             resp_url = resp_url[:-len(qs)]
         if self._url.rstrip('/') != resp_url.rstrip('/'):
             if not self.ui.quiet:
                 self.ui.warn(_('real URL is %s\n') % resp_url)
         self._url = resp_url
         try:
             proto = pycompat.bytesurl(resp.getheader(r'content-type', r''))
         except AttributeError:
             proto = pycompat.bytesurl(resp.headers.get(r'content-type', r''))
 
         safeurl = util.hidepassword(self._url)
         if proto.startswith('application/hg-error'):
             raise error.OutOfBandError(resp.read())
         # accept old "text/plain" and "application/hg-changegroup" for now
         if not (proto.startswith('application/mercurial-') or
                 (proto.startswith('text/plain')
                  and not resp.headers.get('content-length')) or
                 proto.startswith('application/hg-changegroup')):
             self.ui.debug("requested URL: '%s'\n" % util.hidepassword(cu))
             raise error.RepoError(
                 _("'%s' does not appear to be an hg repository:\n"
                   "---%%<--- (%s)\n%s\n---%%<---\n")
                 % (safeurl, proto or 'no content-type', resp.read(1024)))
 
         if proto.startswith('application/mercurial-'):
             try:
                 version = proto.split('-', 1)[1]
                 version_info = tuple([int(n) for n in version.split('.')])
             except ValueError:
                 raise error.RepoError(_("'%s' sent a broken Content-Type "
                                         "header (%s)") % (safeurl, proto))
 
             # TODO consider switching to a decompression reader that uses
             # generators.
             if version_info == (0, 1):
                 if _compressible:
                     return util.compengines['zlib'].decompressorreader(resp)
                 return resp
             elif version_info == (0, 2):
                 # application/mercurial-0.2 always identifies the compression
                 # engine in the payload header.
                 elen = struct.unpack('B', resp.read(1))[0]
                 ename = resp.read(elen)
                 engine = util.compengines.forwiretype(ename)
                 return engine.decompressorreader(resp)
             else:
                 raise error.RepoError(_("'%s' uses newer protocol %s") %
                                       (safeurl, version))
 
         if _compressible:
             return util.compengines['zlib'].decompressorreader(resp)
 
         return resp
 
     def _call(self, cmd, **args):
         fp = self._callstream(cmd, **args)
         try:
             return fp.read()
         finally:
             # if using keepalive, allow connection to be reused
             fp.close()
 
     def _callpush(self, cmd, cg, **args):
         # have to stream bundle to a temp file because we do not have
         # http 1.1 chunked transfer.
 
         types = self.capable('unbundle')
         try:
             types = types.split(',')
         except AttributeError:
             # servers older than d1b16a746db6 will send 'unbundle' as a
             # boolean capability. They only support headerless/uncompressed
             # bundles.
             types = [""]
         for x in types:
             if x in bundle2.bundletypes:
                 type = x
                 break
 
         tempname = bundle2.writebundle(self.ui, cg, None, type)
         fp = httpconnection.httpsendfile(self.ui, tempname, "rb")
         headers = {r'Content-Type': r'application/mercurial-0.1'}
 
         try:
             r = self._call(cmd, data=fp, headers=headers, **args)
             vals = r.split('\n', 1)
             if len(vals) < 2:
                 raise error.ResponseError(_("unexpected response:"), r)
             return vals
         except urlerr.httperror:
             # Catch and re-raise these so we don't try and treat them
             # like generic socket errors. They lack any values in
             # .args on Python 3 which breaks our socket.error block.
             raise
         except socket.error as err:
             if err.args[0] in (errno.ECONNRESET, errno.EPIPE):
                 raise error.Abort(_('push failed: %s') % err.args[1])
             raise error.Abort(err.args[1])
         finally:
             fp.close()
             os.unlink(tempname)
 
     def _calltwowaystream(self, cmd, fp, **args):
         fh = None
         fp_ = None
         filename = None
         try:
             # dump bundle to disk
             fd, filename = tempfile.mkstemp(prefix="hg-bundle-", suffix=".hg")
             fh = os.fdopen(fd, r"wb")
             d = fp.read(4096)
             while d:
                 fh.write(d)
                 d = fp.read(4096)
             fh.close()
             # start http push
             fp_ = httpconnection.httpsendfile(self.ui, filename, "rb")
             headers = {r'Content-Type': r'application/mercurial-0.1'}
             return self._callstream(cmd, data=fp_, headers=headers, **args)
         finally:
             if fp_ is not None:
                 fp_.close()
             if fh is not None:
                 fh.close()
                 os.unlink(filename)
 
     def _callcompressable(self, cmd, **args):
         return self._callstream(cmd, _compressible=True, **args)
 
     def _abort(self, exception):
         raise exception
 
 # TODO implement interface for version 2 peers
 class httpv2peer(object):
     def __init__(self, ui, repourl, opener):
         self.ui = ui
 
         if repourl.endswith('/'):
             repourl = repourl[:-1]
 
         self.url = repourl
         self._opener = opener
         # This is an its own attribute to facilitate extensions overriding
         # the default type.
         self._requestbuilder = urlreq.request
 
     def close(self):
         pass
 
     # TODO require to be part of a batched primitive, use futures.
     def _call(self, name, **args):
         """Call a wire protocol command with arguments."""
 
         # Having this early has a side-effect of importing wireprotov2server,
         # which has the side-effect of ensuring commands are registered.
 
         # TODO modify user-agent to reflect v2.
         headers = {
             r'Accept': wireprotov2server.FRAMINGTYPE,
             r'Content-Type': wireprotov2server.FRAMINGTYPE,
         }
 
         # TODO permissions should come from capabilities results.
         permission = wireproto.commandsv2[name].permission
         if permission not in ('push', 'pull'):
             raise error.ProgrammingError('unknown permission type: %s' %
                                          permission)
 
         permission = {
             'push': 'rw',
             'pull': 'ro',
         }[permission]
 
         url = '%s/api/%s/%s/%s' % (self.url, wireprotov2server.HTTPV2,
                                    permission, name)
 
         # TODO this should be part of a generic peer for the frame-based
         # protocol.
         reactor = wireprotoframing.clientreactor(hasmultiplesend=False,
                                                  buffersends=True)
 
         request, action, meta = reactor.callcommand(name, args)
         assert action == 'noop'
 
         action, meta = reactor.flushcommands()
         assert action == 'sendframes'
 
         body = b''.join(map(bytes, meta['framegen']))
         req = self._requestbuilder(pycompat.strurl(url), body, headers)
         req.add_unredirected_header(r'Content-Length', r'%d' % len(body))
 
         # TODO unify this code with httppeer.
         try:
             res = self._opener.open(req)
         except urlerr.httperror as e:
             if e.code == 401:
                 raise error.Abort(_('authorization failed'))
 
             raise
         except httplib.HTTPException as e:
             self.ui.traceback()
             raise IOError(None, e)
 
         # TODO validate response type, wrap response to handle I/O errors.
         # TODO more robust frame receiver.
         results = []
 
         while True:
             frame = wireprotoframing.readframe(res)
             if frame is None:
                 break
 
             self.ui.note(_('received %r\n') % frame)
 
             action, meta = reactor.onframerecv(frame)
 
             if action == 'responsedata':
                 if meta['cbor']:
                     payload = util.bytesio(meta['data'])
 
                     decoder = cbor.CBORDecoder(payload)
                     while payload.tell() + 1 < len(meta['data']):
                         results.append(decoder.decode())
                 else:
                     results.append(meta['data'])
             else:
                 error.ProgrammingError('unhandled action: %s' % action)
 
         return results
 
 def makepeer(ui, path, requestbuilder=urlreq.request):
     """Construct an appropriate HTTP peer instance.
 
     ``requestbuilder`` is the type used for constructing HTTP requests.
     It exists as an argument so extensions can override the default.
     """
     u = util.url(path)
     if u.query or u.fragment:
         raise error.Abort(_('unsupported URL component: "%s"') %
                           (u.query or u.fragment))
 
     # urllib cannot handle URLs with embedded user or passwd.
     url, authinfo = u.authinfo()
     ui.debug('using %s\n' % url)
 
     opener = urlmod.opener(ui, authinfo)
 
     return httppeer(ui, path, url, opener, requestbuilder)
 
 def instance(ui, path, create):
     if create:
         raise error.Abort(_('cannot create new http repository'))
     try:
         if path.startswith('https:') and not urlmod.has_https:
             raise error.Abort(_('Python support for SSL and HTTPS '
                                 'is not installed'))
 
         inst = makepeer(ui, path)
         inst._fetchcaps()
 
         return inst
     except error.RepoError as httpexception:
         try:
             r = statichttprepo.instance(ui, "static-" + path, create)
             ui.note(_('(falling back to static-http)\n'))
             return r
         except error.RepoError:
             raise httpexception # use the original http RepoError instead