hgweb: add support for extension-provided permission hooks

hgweb: add support for extension-provided permission hooks

This allows extensions to hook into permission checking, providing both
authentication and authorization as needed. The existing authorization
function has been changed to a hook, which is added by default.

--- a/mercurial/hgweb/common.py	Sun Nov 22 19:11:12 2009 +0100
+++ b/mercurial/hgweb/common.py	Mon Nov 23 11:03:55 2009 +0100
@@ -16,6 +16,58 @@
 HTTP_METHOD_NOT_ALLOWED = 405
 HTTP_SERVER_ERROR = 500
 
+# Hooks for hgweb permission checks; extensions can add hooks here. Each hook
+# is invoked like this: hook(hgweb, request, operation), where operation is
+# either read, pull or push. Hooks should either raise an ErrorResponse
+# exception, or just return.
+# It is possible to do both authentication and authorization through this.
+permhooks = []
+
+def checkauthz(hgweb, req, op):
+    '''Check permission for operation based on request data (including
+    authentication info). Return if op allowed, else raise an ErrorResponse
+    exception.'''
+
+    user = req.env.get('REMOTE_USER')
+
+    deny_read = hgweb.configlist('web', 'deny_read')
+    if deny_read and (not user or deny_read == ['*'] or user in deny_read):
+        raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
+
+    allow_read = hgweb.configlist('web', 'allow_read')
+    result = (not allow_read) or (allow_read == ['*'])
+    if not (result or user in allow_read):
+        raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
+
+    if op == 'pull' and not hgweb.allowpull:
+        raise ErrorResponse(HTTP_UNAUTHORIZED, 'pull not authorized')
+    elif op == 'pull' or op is None: # op is None for interface requests
+        return
+
+    # enforce that you can only push using POST requests
+    if req.env['REQUEST_METHOD'] != 'POST':
+        msg = 'push requires POST request'
+        raise ErrorResponse(HTTP_METHOD_NOT_ALLOWED, msg)
+
+    # require ssl by default for pushing, auth info cannot be sniffed
+    # and replayed
+    scheme = req.env.get('wsgi.url_scheme')
+    if hgweb.configbool('web', 'push_ssl', True) and scheme != 'https':
+        raise ErrorResponse(HTTP_OK, 'ssl required')
+
+    deny = hgweb.configlist('web', 'deny_push')
+    if deny and (not user or deny == ['*'] or user in deny):
+        raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
+
+    allow = hgweb.configlist('web', 'allow_push')
+    result = allow and (allow == ['*'] or user in allow)
+    if not result:
+        raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
+
+# Add the default permhook, which provides simple authorization.
+permhooks.append(checkauthz)
+
+
 class ErrorResponse(Exception):
     def __init__(self, code, message=None, headers=[]):
         Exception.__init__(self)

--- a/mercurial/hgweb/hgweb_mod.py	Sun Nov 22 19:11:12 2009 +0100
+++ b/mercurial/hgweb/hgweb_mod.py	Mon Nov 23 11:03:55 2009 +0100
@@ -8,7 +8,7 @@
 
 import os
 from mercurial import ui, hg, hook, error, encoding, templater
-from common import get_mtime, ErrorResponse
+from common import get_mtime, ErrorResponse, permhooks
 from common import HTTP_OK, HTTP_BAD_REQUEST, HTTP_NOT_FOUND, HTTP_SERVER_ERROR
 from common import HTTP_UNAUTHORIZED, HTTP_METHOD_NOT_ALLOWED
 from request import wsgirequest
@@ -283,42 +283,5 @@
         }
 
     def check_perm(self, req, op):
-        '''Check permission for operation based on request data (including
-        authentication info). Return if op allowed, else raise an ErrorResponse
-        exception.'''
-
-        user = req.env.get('REMOTE_USER')
-
-        deny_read = self.configlist('web', 'deny_read')
-        if deny_read and (not user or deny_read == ['*'] or user in deny_read):
-            raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
-
-        allow_read = self.configlist('web', 'allow_read')
-        result = (not allow_read) or (allow_read == ['*'])
-        if not (result or user in allow_read):
-            raise ErrorResponse(HTTP_UNAUTHORIZED, 'read not authorized')
-
-        if op == 'pull' and not self.allowpull:
-            raise ErrorResponse(HTTP_UNAUTHORIZED, 'pull not authorized')
-        elif op == 'pull' or op is None: # op is None for interface requests
-            return
-
-        # enforce that you can only push using POST requests
-        if req.env['REQUEST_METHOD'] != 'POST':
-            msg = 'push requires POST request'
-            raise ErrorResponse(HTTP_METHOD_NOT_ALLOWED, msg)
-
-        # require ssl by default for pushing, auth info cannot be sniffed
-        # and replayed
-        scheme = req.env.get('wsgi.url_scheme')
-        if self.configbool('web', 'push_ssl', True) and scheme != 'https':
-            raise ErrorResponse(HTTP_OK, 'ssl required')
-
-        deny = self.configlist('web', 'deny_push')
-        if deny and (not user or deny == ['*'] or user in deny):
-            raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
-
-        allow = self.configlist('web', 'allow_push')
-        result = allow and (allow == ['*'] or user in allow)
-        if not result:
-            raise ErrorResponse(HTTP_UNAUTHORIZED, 'push not authorized')
+        for hook in permhooks:
+            hook(self, req, op)