Restore support for the "Universal Edit Button"

[Christian Boos]

Well, quite some time ago the browser extensions for the UniversalEditButton stopped working for me, so I forgot about it.

I gave it another try just now, and the extensions are working again for both FF and Chrome (not found any for Opera or Edge). But now it's Trac that has some trouble with the query string used by these extensions:

.../WikiStart?action=edit&version= gives:

Invalid value for request argument version.

Suggested patch:

trac/wiki/web_ui.py

@@ -107 +107 @@
     def process_request(self, req):
         action = req.args.get('action', 'view')
         pagename = req.args.get('page', 'WikiStart')
-        version = req.args.getint('version')
+        version = req.args.as_int('version', None) # for UEB support
         old_version = req.args.getint('old_version')
 
         if pagename.startswith('/') or pagename.endswith('/') or \
@@ -509 +509 @@
                     'WIKI_VIEW' in req.perm(template_page.resource):
                 page.text = template_page.text
         elif 'version' in req.args:
-            version = req.args.getint('version')
-            old_page = WikiPage(self.env, page.name, version)
-            req.perm(page.resource).require('WIKI_VIEW')
-            page.text = old_page.text
-            comment = _("Reverted to version %(version)s.", version=version)
+            version = req.args.as_int('version', None) # for UEB
+            if version is not None:
+                old_page = WikiPage(self.env, page.name, version)
+                req.perm(page.resource).require('WIKI_VIEW')
+                page.text = old_page.text
+                comment = _("Reverted to version %(version)s.",
+                            version=version)
         if action in ('preview', 'diff'):
             page.readonly = 'readonly' in req.args