hgweb: set sent_headers attr as early as practical

While doing Python 3 porting work, I've seen exceptions happen in
parts of hgweb we normally assume are robust. It won't hurt anything
to set this attribute significantly earlier, so let's do so and save
confusing during the porting process.

Differential Revision: https://phab.mercurial-scm.org/D1085

mercurial/hgweb/server.py

@@ -1,347 +1,347 b''
 # 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.
 
 from __future__ import absolute_import
 
 import errno
 import os
 import socket
 import sys
 import traceback
 
 from ..i18n import _
 
 from .. import (
     encoding,
     error,
     pycompat,
     util,
 )
 
 httpservermod = util.httpserver
 socketserver = util.socketserver
 urlerr = util.urlerr
 urlreq = util.urlreq
 
 from . import (
     common,
 )
 
 def _splitURI(uri):
     """Return path and query that has been split from uri
 
     Just like CGI environment, the path is unquoted, the query is
     not.
     """
     if r'?' in uri:
         path, query = uri.split(r'?', 1)
     else:
         path, query = uri, r''
     return urlreq.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(httpservermod.basehttprequesthandler):
 
     url_scheme = 'http'
 
     @staticmethod
     def preparehttpserver(httpserver, ui):
         """Prepare .socket of new HTTPServer instance"""
 
     def __init__(self, *args, **kargs):
         self.protocol_version = r'HTTP/1.1'
         httpservermod.basehttprequesthandler.__init__(self, *args, **kargs)
 
     def _log_any(self, fp, format, *args):
         fp.write(pycompat.sysbytes(
             r"%s - - [%s] %s" % (self.client_address[0],
                                  self.log_date_time_string(),
                                  format % args)) + '\n')
         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=r'-', size=r'-'):
         xheaders = []
         if util.safehasattr(self, 'headers'):
             xheaders = [h for h in self.headers.items()
                         if h[0].startswith(r'x-')]
         self.log_message(r'"%s" %s %s%s',
                          self.requestline, str(code), str(size),
                          r''.join([r' %s:%s' % h for h in sorted(xheaders)]))
 
     def do_write(self):
         try:
             self.do_hgweb()
         except socket.error as 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")
             self._done()
             tb = r"".join(traceback.format_exception(*sys.exc_info()))
             # We need a native-string newline to poke in the log
             # message, because we won't get a newline when using an
             # r-string. This is the easy way out.
             newline = chr(10)
             self.log_error(r"Exception happened during processing "
                            r"request '%s':%s%s", self.path, newline, tb)
 
     def do_GET(self):
         self.do_POST()
 
     def do_hgweb(self):
+        self.sent_headers = False
         path, query = _splitURI(self.path)
 
         env = {}
         env[r'GATEWAY_INTERFACE'] = r'CGI/1.1'
         env[r'REQUEST_METHOD'] = self.command
         env[r'SERVER_NAME'] = self.server.server_name
         env[r'SERVER_PORT'] = str(self.server.server_port)
         env[r'REQUEST_URI'] = self.path
         env[r'SCRIPT_NAME'] = self.server.prefix
         env[r'PATH_INFO'] = path[len(self.server.prefix):]
         env[r'REMOTE_HOST'] = self.client_address[0]
         env[r'REMOTE_ADDR'] = self.client_address[0]
         if query:
             env[r'QUERY_STRING'] = query
 
         if pycompat.ispy3:
             if self.headers.get_content_type() is None:
                 env[r'CONTENT_TYPE'] = self.headers.get_default_type()
             else:
                 env[r'CONTENT_TYPE'] = self.headers.get_content_type()
             length = self.headers.get('content-length')
         else:
             if self.headers.typeheader is None:
                 env[r'CONTENT_TYPE'] = self.headers.type
             else:
                 env[r'CONTENT_TYPE'] = self.headers.typeheader
             length = self.headers.getheader('content-length')
         if length:
             env[r'CONTENT_LENGTH'] = length
         for header in [h for h in self.headers.keys()
                        if h not in ('content-type', 'content-length')]:
             hkey = r'HTTP_' + header.replace(r'-', r'_').upper()
             hval = self.headers.get(header)
             hval = hval.replace(r'\n', r'').strip()
             if hval:
                 env[hkey] = hval
         env[r'SERVER_PROTOCOL'] = self.request_version
         env[r'wsgi.version'] = (1, 0)
         env[r'wsgi.url_scheme'] = self.url_scheme
         if env.get(r'HTTP_EXPECT', '').lower() == '100-continue':
             self.rfile = common.continuereader(self.rfile, self.wfile.write)
 
         env[r'wsgi.input'] = self.rfile
         env[r'wsgi.errors'] = _error_logger(self)
         env[r'wsgi.multithread'] = isinstance(self.server,
                                              socketserver.ThreadingMixIn)
         env[r'wsgi.multiprocess'] = isinstance(self.server,
                                               socketserver.ForkingMixIn)
         env[r'wsgi.run_once'] = 0
 
         self.saved_status = None
         self.saved_headers = []
-        self.sent_headers = False
         self.length = None
         self._chunked = None
         for chunk in self.server.application(env, self._start_response):
             self._write(chunk)
         if not self.sent_headers:
             self.send_headers()
         self._done()
 
     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)
         self.length = None
         self._chunked = False
         for h in self.saved_headers:
             self.send_header(*h)
             if h[0].lower() == 'content-length':
                 self.length = int(h[1])
         if (self.length is None and
             saved_status[0] != common.HTTP_NOT_MODIFIED):
             self._chunked = (not self.close_connection and
                              self.request_version == "HTTP/1.1")
             if self._chunked:
                 self.send_header('Transfer-Encoding', 'chunked')
             else:
                 self.send_header('Connection', '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)
         elif self._chunked and data:
             data = '%x\r\n%s\r\n' % (len(data), data)
         self.wfile.write(data)
         self.wfile.flush()
 
     def _done(self):
         if self._chunked:
             self.wfile.write('0\r\n\r\n')
             self.wfile.flush()
 
 class _httprequesthandlerssl(_httprequesthandler):
     """HTTPS handler based on Python's ssl module"""
 
     url_scheme = 'https'
 
     @staticmethod
     def preparehttpserver(httpserver, ui):
         try:
             from .. import sslutil
             sslutil.modernssl
         except ImportError:
             raise error.Abort(_("SSL support is unavailable"))
 
         certfile = ui.config('web', 'certificate')
 
         # These config options are currently only meant for testing. Use
         # at your own risk.
         cafile = ui.config('devel', 'servercafile')
         reqcert = ui.configbool('devel', 'serverrequirecert')
 
         httpserver.socket = sslutil.wrapserversocket(httpserver.socket,
                                                      ui,
                                                      certfile=certfile,
                                                      cafile=cafile,
                                                      requireclientcert=reqcert)
 
     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:
     import threading
     threading.activeCount() # silence pyflakes and bypass demandimport
     _mixin = socketserver.ThreadingMixIn
 except ImportError:
     if util.safehasattr(os, "fork"):
         _mixin = socketserver.ForkingMixIn
     else:
         class _mixin(object):
             pass
 
 def openlog(opt, default):
     if opt and opt != '-':
         return open(opt, 'a')
     return default
 
 class MercurialHTTPServer(_mixin, httpservermod.httpserver, object):
 
     # SO_REUSEADDR has broken semantics on windows
     if pycompat.iswindows:
         allow_reuse_address = 0
 
     def __init__(self, ui, app, addr, handler, **kwargs):
         httpservermod.httpserver.__init__(self, addr, handler, **kwargs)
         self.daemon_threads = True
         self.application = app
 
         handler.preparehttpserver(self, ui)
 
         prefix = ui.config('web', 'prefix')
         if prefix:
             prefix = '/' + prefix.strip('/')
         self.prefix = prefix
 
         alog = openlog(ui.config('web', 'accesslog'), ui.fout)
         elog = openlog(ui.config('web', 'errorlog'), ui.ferr)
         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'):
         handler = _httprequesthandlerssl
     else:
         handler = _httprequesthandler
 
     if ui.configbool('web', 'ipv6'):
         cls = IPv6HTTPServer
     else:
         cls = MercurialHTTPServer
 
     # ugly hack due to python issue5853 (for threaded use)
     try:
         import mimetypes
         mimetypes.init()
     except UnicodeDecodeError:
         # Python 2.x's mimetypes module attempts to decode strings
         # from Windows' ANSI APIs as ascii (fail), then re-encode them
         # as ascii (clown fail), because the default Python Unicode
         # codec is hardcoded as ascii.
 
         sys.argv # unwrap demand-loader so that reload() works
         reload(sys) # resurrect sys.setdefaultencoding()
         oldenc = sys.getdefaultencoding()
         sys.setdefaultencoding("latin1") # or any full 8-bit encoding
         mimetypes.init()
         sys.setdefaultencoding(oldenc)
 
     address = ui.config('web', 'address')
     port = util.getport(ui.config('web', 'port'))
     try:
         return cls(ui, app, (address, port), handler)
     except socket.error as inst:
         raise error.Abort(_("cannot start server at '%s:%d': %s")
                           % (address, port, encoding.strtolocal(inst.args[1])))