mercurial/hgweb/server.py

httprepo: long arguments support (issue2126)

Send the command arguments in the HTTP headers. The command is still part
of the URL. If the server does not have the 'httpheader' capability, the
client will send the command arguments in the URL as it did previously.

Web servers typically allow more data to be placed within the headers than
in the URL, so this approach will:
- Avoid HTTP errors due to using a URL that is too large.
- Allow Mercurial to implement a more efficient wire protocol.

An alternate approach is to send the arguments as part of the request body.
This approach has been rejected because it requires the use of POST
requests, so it would break any existing configuration that relies on the
request type for authentication or caching.

Extensibility:
- The header size is provided by the server, which makes it possible to
  introduce an hgrc setting for it.
- The client ignores the capability value after the first comma, which
  allows more information to be included in the future.

# hgweb/server.py - The standalone hg web server.
#
# Copyright 21 May 2005 - (c) 2005 Jake Edge <[e-mail]>
# Copyright 2005-2007 Matt Mackall <[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.

import os, sys, errno, urllib, BaseHTTPServer, socket, SocketServer, traceback
from mercurial import util, error
from mercurial.hgweb import common
from mercurial.i18n import _

def _splitURI(uri):
    """ Return path and query splited from uri

    Just like CGI environment, the path is unquoted, the query is
    not.
    """
    if '?' in uri:
        path, query = uri.split('?', 1)
    else:
        path, query = uri, ''
    return urllib.unquote(path), query

class _error_logger(object):
    def __init__(self, handler):
        self.handler = handler
    def flush(self):
        pass
    def write(self, str):
        self.writelines(str.split('\n'))
    def writelines(self, seq):
        for msg in seq:
            self.handler.log_error("HG error:  %s", msg)

class _httprequesthandler(BaseHTTPServer.BaseHTTPRequestHandler):

    url_scheme = 'http'

    @staticmethod
    def preparehttpserver(httpserver, ssl_cert):
        """Prepare .socket of new HTTPServer instance"""
        pass

    def __init__(self, *args, **kargs):
        self.protocol_version = 'HTTP/1.1'
        BaseHTTPServer.BaseHTTPRequestHandler.__init__(self, *args, **kargs)

    def _log_any(self, fp, format, *args):
        fp.write("%s - - [%s] %s\n" % (self.client_address[0],
                                       self.log_date_time_string(),
                                       format % args))
        fp.flush()

    def log_error(self, format, *args):
        self._log_any(self.server.errorlog, format, *args)

    def log_message(self, format, *args):
        self._log_any(self.server.accesslog, format, *args)

    def log_request(self, code='-', size='-'):
        xheaders = [h for h in self.headers.items() if h[0].startswith('x-')]
        self.log_message('"%s" %s %s%s',
                         self.requestline, str(code), str(size),
                         ''.join([' %s:%s' % h for h in sorted(xheaders)]))

    def do_write(self):
        try:
            self.do_hgweb()
        except socket.error, inst:
            if inst[0] != errno.EPIPE:
                raise

    def do_POST(self):
        try:
            self.do_write()
        except Exception:
            self._start_response("500 Internal Server Error", [])
            self._write("Internal Server Error")
            tb = "".join(traceback.format_exception(*sys.exc_info()))
            self.log_error("Exception happened during processing "
                           "request '%s':\n%s", self.path, tb)

    def do_GET(self):
        self.do_POST()

    def do_hgweb(self):
        path, query = _splitURI(self.path)

        env = {}
        env['GATEWAY_INTERFACE'] = 'CGI/1.1'
        env['REQUEST_METHOD'] = self.command
        env['SERVER_NAME'] = self.server.server_name
        env['SERVER_PORT'] = str(self.server.server_port)
        env['REQUEST_URI'] = self.path
        env['SCRIPT_NAME'] = self.server.prefix
        env['PATH_INFO'] = path[len(self.server.prefix):]
        env['REMOTE_HOST'] = self.client_address[0]
        env['REMOTE_ADDR'] = self.client_address[0]
        if query:
            env['QUERY_STRING'] = query

        if self.headers.typeheader is None:
            env['CONTENT_TYPE'] = self.headers.type
        else:
            env['CONTENT_TYPE'] = self.headers.typeheader
        length = self.headers.getheader('content-length')
        if length:
            env['CONTENT_LENGTH'] = length
        for header in [h for h in self.headers.keys()
                       if h not in ('content-type', 'content-length')]:
            hkey = 'HTTP_' + header.replace('-', '_').upper()
            hval = self.headers.getheader(header)
            hval = hval.replace('\n', '').strip()
            if hval:
                env[hkey] = hval
        env['SERVER_PROTOCOL'] = self.request_version
        env['wsgi.version'] = (1, 0)
        env['wsgi.url_scheme'] = self.url_scheme
        if env.get('HTTP_EXPECT', '').lower() == '100-continue':
            self.rfile = common.continuereader(self.rfile, self.wfile.write)

        env['wsgi.input'] = self.rfile
        env['wsgi.errors'] = _error_logger(self)
        env['wsgi.multithread'] = isinstance(self.server,
                                             SocketServer.ThreadingMixIn)
        env['wsgi.multiprocess'] = isinstance(self.server,
                                              SocketServer.ForkingMixIn)
        env['wsgi.run_once'] = 0

        self.close_connection = True
        self.saved_status = None
        self.saved_headers = []
        self.sent_headers = False
        self.length = None
        for chunk in self.server.application(env, self._start_response):
            self._write(chunk)

    def send_headers(self):
        if not self.saved_status:
            raise AssertionError("Sending headers before "
                                 "start_response() called")
        saved_status = self.saved_status.split(None, 1)
        saved_status[0] = int(saved_status[0])
        self.send_response(*saved_status)
        should_close = True
        for h in self.saved_headers:
            self.send_header(*h)
            if h[0].lower() == 'content-length':
                should_close = False
                self.length = int(h[1])
        # The value of the Connection header is a list of case-insensitive
        # tokens separated by commas and optional whitespace.
        if 'close' in [token.strip().lower() for token in
                       self.headers.get('connection', '').split(',')]:
            should_close = True
        if should_close:
            self.send_header('Connection', 'close')
        self.close_connection = should_close
        self.end_headers()
        self.sent_headers = True

    def _start_response(self, http_status, headers, exc_info=None):
        code, msg = http_status.split(None, 1)
        code = int(code)
        self.saved_status = http_status
        bad_headers = ('connection', 'transfer-encoding')
        self.saved_headers = [h for h in headers
                              if h[0].lower() not in bad_headers]
        return self._write

    def _write(self, data):
        if not self.saved_status:
            raise AssertionError("data written before start_response() called")
        elif not self.sent_headers:
            self.send_headers()
        if self.length is not None:
            if len(data) > self.length:
                raise AssertionError("Content-length header sent, but more "
                                     "bytes than specified are being written.")
            self.length = self.length - len(data)
        self.wfile.write(data)
        self.wfile.flush()

class _httprequesthandleropenssl(_httprequesthandler):
    """HTTPS handler based on pyOpenSSL"""

    url_scheme = 'https'

    @staticmethod
    def preparehttpserver(httpserver, ssl_cert):
        try:
            import OpenSSL
            OpenSSL.SSL.Context
        except ImportError:
            raise util.Abort(_("SSL support is unavailable"))
        ctx = OpenSSL.SSL.Context(OpenSSL.SSL.SSLv23_METHOD)
        ctx.use_privatekey_file(ssl_cert)
        ctx.use_certificate_file(ssl_cert)
        sock = socket.socket(httpserver.address_family, httpserver.socket_type)
        httpserver.socket = OpenSSL.SSL.Connection(ctx, sock)
        httpserver.server_bind()
        httpserver.server_activate()

    def setup(self):
        self.connection = self.request
        self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
        self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)

    def do_write(self):
        import OpenSSL
        try:
            _httprequesthandler.do_write(self)
        except OpenSSL.SSL.SysCallError, inst:
            if inst.args[0] != errno.EPIPE:
                raise

    def handle_one_request(self):
        import OpenSSL
        try:
            _httprequesthandler.handle_one_request(self)
        except (OpenSSL.SSL.SysCallError, OpenSSL.SSL.ZeroReturnError):
            self.close_connection = True
            pass

class _httprequesthandlerssl(_httprequesthandler):
    """HTTPS handler based on Pythons ssl module (introduced in 2.6)"""

    url_scheme = 'https'

    @staticmethod
    def preparehttpserver(httpserver, ssl_cert):
        try:
            import ssl
            ssl.wrap_socket
        except ImportError:
            raise util.Abort(_("SSL support is unavailable"))
        httpserver.socket = ssl.wrap_socket(httpserver.socket, server_side=True,
            certfile=ssl_cert, ssl_version=ssl.PROTOCOL_SSLv23)

    def setup(self):
        self.connection = self.request
        self.rfile = socket._fileobject(self.request, "rb", self.rbufsize)
        self.wfile = socket._fileobject(self.request, "wb", self.wbufsize)

try:
    from threading import activeCount
    _mixin = SocketServer.ThreadingMixIn
except ImportError:
    if hasattr(os, "fork"):
        _mixin = SocketServer.ForkingMixIn
    else:
        class _mixin:
            pass

def openlog(opt, default):
    if opt and opt != '-':
        return open(opt, 'a')
    return default

class MercurialHTTPServer(object, _mixin, BaseHTTPServer.HTTPServer):

    # SO_REUSEADDR has broken semantics on windows
    if os.name == 'nt':
        allow_reuse_address = 0

    def __init__(self, ui, app, addr, handler, **kwargs):
        BaseHTTPServer.HTTPServer.__init__(self, addr, handler, **kwargs)
        self.daemon_threads = True
        self.application = app

        handler.preparehttpserver(self, ui.config('web', 'certificate'))

        prefix = ui.config('web', 'prefix', '')
        if prefix:
            prefix = '/' + prefix.strip('/')
        self.prefix = prefix

        alog = openlog(ui.config('web', 'accesslog', '-'), sys.stdout)
        elog = openlog(ui.config('web', 'errorlog', '-'), sys.stderr)
        self.accesslog = alog
        self.errorlog = elog

        self.addr, self.port = self.socket.getsockname()[0:2]
        self.fqaddr = socket.getfqdn(addr[0])

class IPv6HTTPServer(MercurialHTTPServer):
    address_family = getattr(socket, 'AF_INET6', None)
    def __init__(self, *args, **kwargs):
        if self.address_family is None:
            raise error.RepoError(_('IPv6 is not available on this system'))
        super(IPv6HTTPServer, self).__init__(*args, **kwargs)

def create_server(ui, app):

    if ui.config('web', 'certificate'):
        if sys.version_info >= (2, 6):
            handler = _httprequesthandlerssl
        else:
            handler = _httprequesthandleropenssl
    else:
        handler = _httprequesthandler

    if ui.configbool('web', 'ipv6'):
        cls = IPv6HTTPServer
    else:
        cls = MercurialHTTPServer

    # ugly hack due to python issue5853 (for threaded use)
    import mimetypes; mimetypes.init()

    address = ui.config('web', 'address', '')
    port = util.getport(ui.config('web', 'port', 8000))
    try:
        return cls(ui, app, (address, port), handler)
    except socket.error, inst:
        raise util.Abort(_("cannot start server at '%s:%d': %s")
                         % (address, port, inst.args[1]))