diff --git a/mercurial/hgweb/hgweb_mod.py b/mercurial/hgweb/hgweb_mod.py
--- a/mercurial/hgweb/hgweb_mod.py
+++ b/mercurial/hgweb/hgweb_mod.py
@@ -6,7 +6,7 @@
 # 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
+import os, zlib
 from mercurial import ui, hg, hook, error, encoding, templater, wireproto
 from common import get_mtime, ErrorResponse, permhooks
 from common import HTTP_OK, HTTP_BAD_REQUEST, HTTP_NOT_FOUND, HTTP_SERVER_ERROR
@@ -22,6 +22,7 @@ perms = {
     'pushkey': 'push',
 }
 
+HGTYPE = 'application/mercurial-0.1'
 class webproto(object):
     def __init__(self, req):
         self.req = req
@@ -39,8 +40,17 @@ class webproto(object):
             else:
                 data[k] = self.req.form[k][0]
         return [data[k] for k in keys]
+    def sendchangegroup(self, cg):
+        self.req.respond(HTTP_OK, HGTYPE)
+        z = zlib.compressobj()
+        while 1:
+            chunk = cg.read(4096)
+            if not chunk:
+                break
+            self.req.write(z.compress(chunk))
+        self.req.write(z.flush())
+
     def respond(self, s):
-        HGTYPE = 'application/mercurial-0.1'
         self.req.respond(HTTP_OK, HGTYPE, length=len(s))
         self.response = s
 
diff --git a/mercurial/hgweb/protocol.py b/mercurial/hgweb/protocol.py
--- a/mercurial/hgweb/protocol.py
+++ b/mercurial/hgweb/protocol.py
@@ -23,43 +23,6 @@ from common import ErrorResponse, HTTP_O
 HGTYPE = 'application/mercurial-0.1'
 basecaps = 'lookup changegroupsubset branchmap pushkey'.split()
 
-def changegroup(repo, req):
-    req.respond(HTTP_OK, HGTYPE)
-    nodes = []
-
-    if 'roots' in req.form:
-        nodes = map(bin, req.form['roots'][0].split(" "))
-
-    z = zlib.compressobj()
-    f = repo.changegroup(nodes, 'serve')
-    while 1:
-        chunk = f.read(4096)
-        if not chunk:
-            break
-        yield z.compress(chunk)
-
-    yield z.flush()
-
-def changegroupsubset(repo, req):
-    req.respond(HTTP_OK, HGTYPE)
-    bases = []
-    heads = []
-
-    if 'bases' in req.form:
-        bases = [bin(x) for x in req.form['bases'][0].split(' ')]
-    if 'heads' in req.form:
-        heads = [bin(x) for x in req.form['heads'][0].split(' ')]
-
-    z = zlib.compressobj()
-    f = repo.changegroupsubset(bases, heads, 'serve')
-    while 1:
-        chunk = f.read(4096)
-        if not chunk:
-            break
-        yield z.compress(chunk)
-
-    yield z.flush()
-
 def capabilities(repo, req):
     caps = copy.copy(basecaps)
     if streamclone.allowed(repo.ui):
diff --git a/mercurial/sshserver.py b/mercurial/sshserver.py
--- a/mercurial/sshserver.py
+++ b/mercurial/sshserver.py
@@ -58,6 +58,15 @@ class sshserver(object):
         self.fout.write(v)
         self.fout.flush()
 
+    def sendchangegroup(self, changegroup):
+        while True:
+            d = changegroup.read(4096)
+            if not d:
+                break
+            self.fout.write(d)
+
+        self.fout.flush()
+
     def serve_forever(self):
         try:
             while self.serve_one():
@@ -105,34 +114,6 @@ class sshserver(object):
         self.lock = None
         return ""
 
-    def do_changegroup(self):
-        nodes = []
-        roots = self.getarg('roots')
-        nodes = map(bin, roots.split(" "))
-
-        cg = self.repo.changegroup(nodes, 'serve')
-        while True:
-            d = cg.read(4096)
-            if not d:
-                break
-            self.fout.write(d)
-
-        self.fout.flush()
-
-    def do_changegroupsubset(self):
-        bases, heads = self.getargs('bases heads')
-        bases = [bin(n) for n in bases.split(' ')]
-        heads = [bin(n) for n in heads.split(' ')]
-
-        cg = self.repo.changegroupsubset(bases, heads, 'serve')
-        while True:
-            d = cg.read(4096)
-            if not d:
-                break
-            self.fout.write(d)
-
-        self.fout.flush()
-
     def do_addchangegroup(self):
         '''DEPRECATED'''
 
diff --git a/mercurial/wireproto.py b/mercurial/wireproto.py
--- a/mercurial/wireproto.py
+++ b/mercurial/wireproto.py
@@ -15,7 +15,9 @@ def dispatch(repo, proto, command):
         return False
     func, spec = commands[command]
     args = proto.getargs(spec)
-    proto.respond(func(repo, proto, *args))
+    r = func(repo, proto, *args)
+    if r != None:
+        proto.respond(r)
     return True
 
 def between(repo, proto, pairs):
@@ -41,6 +43,17 @@ def branches(repo, proto, nodes):
         r.append(" ".join(map(hex, b)) + "\n")
     return "".join(r)
 
+def changegroup(repo, proto, roots):
+    nodes = map(bin, roots.split(" "))
+    cg = repo.changegroup(nodes, 'serve')
+    proto.sendchangegroup(cg)
+
+def changegroupsubset(repo, proto, bases, heads):
+    bases = [bin(n) for n in bases.split(' ')]
+    heads = [bin(n) for n in heads.split(' ')]
+    cg = repo.changegroupsubset(bases, heads, 'serve')
+    proto.sendchangegroup(cg)
+
 def heads(repo, proto):
     h = repo.heads()
     return " ".join(map(hex, h)) + "\n"
@@ -68,6 +81,8 @@ commands = {
     'between': (between, 'pairs'),
     'branchmap': (branchmap, ''),
     'branches': (branches, 'nodes'),
+    'changegroup': (changegroup, 'roots'),
+    'changegroupsubset': (changegroupsubset, 'bases heads'),
     'heads': (heads, ''),
     'listkeys': (listkeys, 'namespace'),
     'lookup': (lookup, 'key'),
diff --git a/tests/test-clone-cgi b/tests/test-clone-cgi
--- a/tests/test-clone-cgi
+++ b/tests/test-clone-cgi
@@ -55,7 +55,7 @@ SERVER_SIGNATURE="<address>Apache/2.0.53
 SERVER_SOFTWARE="Apache/2.0.53 (Fedora)"; export SERVER_SOFTWARE
 
 echo % try hgweb request
-QUERY_STRING="cmd=changegroup"; export QUERY_STRING
+QUERY_STRING="cmd=changegroup&roots=0000000000000000000000000000000000000000"; export QUERY_STRING
 python hgweb.cgi >page1 2>&1 ; echo $?
 python "$TESTDIR/md5sum.py" page1
 
diff --git a/tests/test-hgweb-commands b/tests/test-hgweb-commands
--- a/tests/test-hgweb-commands
+++ b/tests/test-hgweb-commands
@@ -50,7 +50,7 @@ echo % lookup
 echo % branches
 "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '?cmd=branches&nodes=0000000000000000000000000000000000000000'
 echo % changegroup
-"$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '?cmd=changegroup' \
+"$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '?cmd=changegroup&roots=0000000000000000000000000000000000000000' \
     | $TESTDIR/printrepr.py
 echo % stream_out
 "$TESTDIR/get-with-headers.py" 127.0.0.1:$HGPORT '?cmd=stream_out'