URL Redirect Management
Whenever a document is published, and this causes changes to its URL (and any of its descendants' URLs), Umbraco saves the old URLs. Whenever an incoming request is served and the default content finders cannot find a matching document, Umbraco checks whether the URL matches one of these saved URLs. If a match is found, Umbraco returns a "301 Redirect" answer pointing to the new URL of the document.
Umbraco does not support rewriting "rules" (e.g. regular expressions) nor complex scenarios (e.g. changing the culture and hostnames configuration). There already are powerful solutions to deal what that type of situations, such as Microsoft's own Url Rewrite module for IIS.
It is possible to list the redirect URLs via the Redirect Url Management dashboard in the Developer section. This dashboard lists the original URL, new URL, and date. It allows you to delete a URL, and to directly edit the corresponding document.
In addition, the dashboard can be used to disable or enable the 301 Redirect Management (via the
web.routing configuration attribute described below - note that this causes an application restart).
Anytime a document is published and its corresponding url segment changes, Umbraco checks its URL (and all its descendants' URLs) for changes. For every URL that has changed, it creates (or updates) a row in the
umbracoRedirectUrl table. Rows in this table contain: the old url, the create date, and the target content identifier.
Umbraco registers a new content finder,
ContentFinderByRedirectUrl, which runs as a normal content finder after the other content finders. It looks for the incoming URL in the database table and, if found, computes the URL of the target document and returns a "301 Redirect". These redirects are considered "permanent". It's good to note that we explicitly set
no-cache headers on these redirects so that when they change, browsers update the URL immediately. They are a "true" 301, however and search engines will accept them as such.
Enable / Disable / Configure
The 301 Redirect Management feature is enabled by default.
It is possible to disable the feature entirely (both generating URLs in the database table, and running the content finder) by editing the
<web.routing disableRedirectUrlTracking="true" />
In addition, Umbraco will automatically disable the feature if it detects any DLL whose name would contain any of the following strings:
"InfoCaster.Umbraco.UrlTracker" "SEOChecker" "Simple301" "Terabyte.Umbraco.Modules.PermanentRedirect" "CMUmbracoTools" "PWUrlRedirect"
These products already implement redirect management and we do not want to interfere.