--- a/hgweb.cgi
+++ b/hgweb.cgi
@@ -6,7 +6,11 @@ import cgitb, os, sys
 cgitb.enable()
 
 # sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
-from mercurial import hgweb
+from mercurial.hgweb.hgweb_mod import hgweb
+from mercurial.hgweb.request import wsgiapplication
+import mercurial.hgweb.wsgicgi as wsgicgi
 
-h = hgweb.hgweb("/path/to/repo", "repository name")
-h.run()
+def make_web_app():
+    return hgweb("/path/to/repo", "repository name")
+
+wsgicgi.launch(wsgiapplication(make_web_app))

--- a/hgwebdir.cgi
+++ b/hgwebdir.cgi
@@ -6,7 +6,9 @@ import cgitb, sys
 cgitb.enable()
 
 # sys.path.insert(0, "/path/to/python/lib") # if not a system-wide install
-from mercurial import hgweb
+from mercurial.hgweb.hgwebdir_mod import hgwebdir
+from mercurial.hgweb.request import wsgiapplication
+import mercurial.hgweb.wsgicgi as wsgicgi
 
 # The config file looks like this.  You can have paths to individual
 # repos, collections of repos in a directory tree, or both.
@@ -27,5 +29,7 @@ from mercurial import hgweb
 # Alternatively you can pass a list of ('virtual/path', '/real/path') tuples
 # or use a dictionary with entries like 'virtual/path': '/real/path'
 
-h = hgweb.hgwebdir("hgweb.config")
-h.run()
+def make_web_app():
+    return hgwebdir("hgweb.config")
+
+wsgicgi.launch(wsgiapplication(make_web_app))

--- a/mercurial/hgweb/hgweb_mod.py
+++ b/mercurial/hgweb/hgweb_mod.py
@@ -12,7 +12,6 @@ import mimetypes
 from mercurial.demandload import demandload
 demandload(globals(), "re zlib ConfigParser cStringIO sys tempfile")
 demandload(globals(), "mercurial:mdiff,ui,hg,util,archival,templater")
-demandload(globals(), "mercurial.hgweb.request:hgrequest")
 demandload(globals(), "mercurial.hgweb.common:get_mtime,staticfile")
 from mercurial.node import *
 from mercurial.i18n import gettext as _
@@ -652,7 +651,7 @@ class hgweb(object):
             raise Exception("suspicious path")
         return p
 
-    def run(self, req=hgrequest()):
+    def run(self, req):
         def header(**map):
             yield self.t("header", **map)
 
@@ -725,7 +724,6 @@ class hgweb(object):
             method(req)
         else:
             req.write(self.t("error"))
-        req.done()
 
     def do_changelog(self, req):
         hi = self.repo.changelog.count() - 1

--- a/mercurial/hgweb/hgwebdir_mod.py
+++ b/mercurial/hgweb/hgwebdir_mod.py
@@ -11,7 +11,6 @@ from mercurial.demandload import demandl
 demandload(globals(), "ConfigParser")
 demandload(globals(), "mercurial:ui,hg,util,templater")
 demandload(globals(), "mercurial.hgweb.hgweb_mod:hgweb")
-demandload(globals(), "mercurial.hgweb.request:hgrequest")
 demandload(globals(), "mercurial.hgweb.common:get_mtime,staticfile")
 from mercurial.i18n import gettext as _
 
@@ -47,7 +46,7 @@ class hgwebdir(object):
                         self.repos.append((name.lstrip(os.sep), repo))
             self.repos.sort()
 
-    def run(self, req=hgrequest()):
+    def run(self, req):
         def header(**map):
             yield tmpl("header", **map)
 

--- a/mercurial/hgweb/request.py
+++ b/mercurial/hgweb/request.py
@@ -10,40 +10,73 @@ from mercurial.demandload import demandl
 demandload(globals(), "socket sys cgi os errno")
 from mercurial.i18n import gettext as _
 
-class hgrequest(object):
-    def __init__(self, inp=None, out=None, env=None):
-        self.inp = inp or sys.stdin
-        self.out = out or sys.stdout
-        self.env = env or os.environ
+class wsgiapplication(object):
+    def __init__(self, destmaker):
+        self.destmaker = destmaker
+
+    def __call__(self, wsgienv, start_response):
+        return _wsgirequest(self.destmaker(), wsgienv, start_response)
+
+class _wsgioutputfile(object):
+    def __init__(self, request):
+        self.request = request
+
+    def write(self, data):
+        self.request.write(data)
+    def writelines(self, lines):
+        for line in lines:
+            self.write(line)
+    def flush(self):
+        return None
+    def close(self):
+        return None
+
+class _wsgirequest(object):
+    def __init__(self, destination, wsgienv, start_response):
+        version = wsgienv['wsgi.version']
+        if (version < (1,0)) or (version >= (2, 0)):
+            raise RuntimeError("Unknown and unsupported WSGI version %d.%d" \
+                               % version)
+        self.inp = wsgienv['wsgi.input']
+        self.out = _wsgioutputfile(self)
+        self.server_write = None
+        self.err = wsgienv['wsgi.errors']
+        self.threaded = wsgienv['wsgi.multithread']
+        self.multiprocess = wsgienv['wsgi.multiprocess']
+        self.run_once = wsgienv['wsgi.run_once']
+        self.env = wsgienv
         self.form = cgi.parse(self.inp, self.env, keep_blank_values=1)
-        self.will_close = True
+        self.start_response = start_response
+        self.headers = []
+        destination.run(self)
+
+    def __iter__(self):
+        return iter([])
 
     def read(self, count=-1):
         return self.inp.read(count)
 
     def write(self, *things):
+        if self.server_write is None:
+            if not self.headers:
+                raise RuntimeError("request.write called before headers sent.")
+            self.server_write = self.start_response('200 Script output follows',
+                                                    self.headers)
+            self.start_response = None
+            self.headers = None
         for thing in things:
             if hasattr(thing, "__iter__"):
                 for part in thing:
                     self.write(part)
             else:
                 try:
-                    self.out.write(str(thing))
+                    self.server_write(str(thing))
                 except socket.error, inst:
                     if inst[0] != errno.ECONNRESET:
                         raise
 
-    def done(self):
-        if self.will_close:
-            self.inp.close()
-            self.out.close()
-        else:
-            self.out.flush()
-
     def header(self, headers=[('Content-type','text/html')]):
-        for header in headers:
-            self.out.write("%s: %s\r\n" % header)
-        self.out.write("\r\n")
+        self.headers.extend(headers)
 
     def httphdr(self, type, filename=None, length=0, headers={}):
         headers = headers.items()
@@ -51,12 +84,6 @@ class hgrequest(object):
         if filename:
             headers.append(('Content-disposition', 'attachment; filename=%s' %
                             filename))
-        # we do not yet support http 1.1 chunked transfer, so we have
-        # to force connection to close if content-length not known
         if length:
             headers.append(('Content-length', str(length)))
-            self.will_close = False
-        else:
-            headers.append(('Connection', 'close'))
-            self.will_close = True
         self.header(headers)

--- a/mercurial/hgweb/server.py
+++ b/mercurial/hgweb/server.py
@@ -10,7 +10,7 @@ from mercurial.demandload import demandl
 import os, sys, errno
 demandload(globals(), "urllib BaseHTTPServer socket SocketServer")
 demandload(globals(), "mercurial:ui,hg,util,templater")
-demandload(globals(), "hgweb_mod:hgweb hgwebdir_mod:hgwebdir request:hgrequest")
+demandload(globals(), "hgweb_mod:hgweb hgwebdir_mod:hgwebdir request:wsgiapplication")
 from mercurial.i18n import gettext as _
 
 def _splitURI(uri):
@@ -25,6 +25,17 @@ def _splitURI(uri):
         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(str):
+        self.writelines(str.split('\n'))
+    def writelines(seq):
+        for msg in seq:
+            self.handler.log_error("HG error:  %s", msg)
+
 class _hgwebhandler(object, BaseHTTPServer.BaseHTTPRequestHandler):
     def __init__(self, *args, **kargs):
         self.protocol_version = 'HTTP/1.1'
@@ -84,10 +95,50 @@ class _hgwebhandler(object, BaseHTTPServ
             if hval:
                 env[hkey] = hval
         env['SERVER_PROTOCOL'] = self.request_version
+        env['wsgi.version'] = (1, 0)
+        env['wsgi.url_scheme'] = 'http'
+        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
 
-        req = hgrequest(self.rfile, self.wfile, env)
-        self.send_response(200, "Script output follows")
-        self.close_connection = self.server.make_and_run_handler(req)
+        self.close_connection = True
+        self.saved_status = None
+        self.saved_headers = []
+        self.sent_headers = False
+        req = self.server.reqmaker(env, self._start_response)
+        for data in req:
+            if data:
+                self._write(data)
+
+    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)
+        for h in self.saved_headers:
+            self.send_header(*h)
+        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
+        self.saved_headers = 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()
+        self.wfile.write(data)
+        self.wfile.flush()
 
 def create_server(ui, repo):
     use_threads = True
@@ -127,8 +178,9 @@ def create_server(ui, repo):
             self.webdir_conf = webdir_conf
             self.webdirmaker = hgwebdir
             self.repoviewmaker = hgweb
+            self.reqmaker = wsgiapplication(self.make_handler)
 
-        def make_and_run_handler(self, req):
+        def make_handler(self):
             if self.webdir_conf:
                 hgwebobj = self.webdirmaker(self.webdir_conf)
             elif self.repo is not None:
@@ -136,8 +188,7 @@ def create_server(ui, repo):
                                                              repo.origroot))
             else:
                 raise hg.RepoError(_('no repo found'))
-            hgwebobj.run(req)
-            return req.will_close
+            return hgwebobj
 
     class IPv6HTTPServer(MercurialHTTPServer):
         address_family = getattr(socket, 'AF_INET6', None)

new file mode 100644
--- /dev/null
+++ b/mercurial/hgweb/wsgicgi.py
@@ -0,0 +1,69 @@
+# hgweb/wsgicgi.py - CGI->WSGI translator
+#
+# Copyright 2006 Eric Hopper <hopper@omnifarious.org>
+#
+# This software may be used and distributed according to the terms
+# of the GNU General Public License, incorporated herein by reference.
+#
+# This was originally copied from the public domain code at
+# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side
+
+import os, sys
+
+def launch(application):
+
+    environ = dict(os.environ.items())
+    environ['wsgi.input']        = sys.stdin
+    environ['wsgi.errors']       = sys.stderr
+    environ['wsgi.version']      = (1,0)
+    environ['wsgi.multithread']  = False
+    environ['wsgi.multiprocess'] = True
+    environ['wsgi.run_once']    = True
+
+    if environ.get('HTTPS','off') in ('on','1'):
+        environ['wsgi.url_scheme'] = 'https'
+    else:
+        environ['wsgi.url_scheme'] = 'http'
+
+    headers_set = []
+    headers_sent = []
+
+    def write(data):
+        if not headers_set:
+             raise AssertionError("write() before start_response()")
+
+        elif not headers_sent:
+             # Before the first output, send the stored headers
+             status, response_headers = headers_sent[:] = headers_set
+             sys.stdout.write('Status: %s\r\n' % status)
+             for header in response_headers:
+                 sys.stdout.write('%s: %s\r\n' % header)
+             sys.stdout.write('\r\n')
+
+        sys.stdout.write(data)
+        sys.stdout.flush()
+
+    def start_response(status,response_headers,exc_info=None):
+        if exc_info:
+            try:
+                if headers_sent:
+                    # Re-raise original exception if headers sent
+                    raise exc_info[0], exc_info[1], exc_info[2]
+            finally:
+                exc_info = None     # avoid dangling circular ref
+        elif headers_set:
+            raise AssertionError("Headers already set!")
+
+        headers_set[:] = [status,response_headers]
+        return write
+
+    result = application(environ, start_response)
+    try:
+        for data in result:
+            if data:    # don't send headers until body appears
+                write(data)
+        if not headers_sent:
+            write('')   # send headers now if body was empty
+    finally:
+        if hasattr(result,'close'):
+            result.close()