404 'not found' and 403 'forbidden' error handlers. The 404 handler shows custom content for missing pages but not resources like CSS or JS. The 403 handler redirects to a login URL on unauthorized access.

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0.4.2 2022-07-11 12:02 UTC


A set of error handlers that extends TYPO3's default site error handling.

Available Handlers

Page Not Found (HTTP Status 404)

Shows content from a page or external URL.

If the resource is unavailable or the content is empty, a message in the standard TYPO3 error layout is shown.

When the requested URL denotes a web resource (eg a CSS file) only a small response is sent to save bandwidth ("Regular expression for resource file extensions", see Extension Manager Configuration).

The file extensions to be treated by default as web resources:

  • css
  • eot, ttf, woff, woff2
  • gif, ico, jpg, jpeg, png, svg, webp
  • js
  • json
  • xml

Forbidden (HTTP Status 403)

Redirects to a login URL if access to page without a session is not permitted.

If the user is already logged in, but has no access because of missing group rights he will be optionally redirected to a fallback page ("Show Content from Page on Missing Permissions", see Site Configuration).

In any other case a 404 "not found" error is triggered. TYPO3 will invoke the configured error handler.


The error pages are cached in the page cache of TYPO3. If TYPO3 pages are configured (and not external URLs) then the cache is invalidated automatically if the page content changes.


  • TYPO3 9 LTS, 10 LTS, 11 LTS, 12 LTS
  • 404: A page/URL that contains a human-readable "page not found" message
  • 403: A URL that performs a login and a redirect to a supplied URL (eg. extension "felogin")
  • the web server must be able to reach itself under the configured domain


Add via composer.json:

"require": {
  "plan2net/sierrha": "*"

Install and activate the extension in the Extension manager.

Extension Manager Configuration

Regular Expression For Resource File Extensions:

This is the default regular expression.


Enable Debug Mode:

In case of configuration errors a detailed error will be shown when in debug mode or if the HTTP request comes from an IP listed in $GLOBALS['TYPO3_CONF_VARS']['SYS']['devIPmask']. Otherwise, the error will be passed on to be handled by TYPO3.

Site Configuration

404 "not found"

On tab "Error Handling" create a new handler.

HTTP Error Status Code: "404" How to handle Errors: "PHP Class"

Save the configuration.

ErrorHandler Class Target (FQCN): "Plan2net\Sierrha\Error\StatusNotFoundHandler" Show Content from Page on Not Found: TYPO3 page or external URL

403 "forbidden"

On tab "Error Handling" create a new handler.

HTTP Error Status Code: "403" How to handle Errors: "PHP Class"

Save the configuration.

ErrorHandler Class Target (FQCN): "Plan2net\Sierrha\Error\StatusForbiddenHandler" Login Page: TYPO3 page or external URL Show Content from Page on Missing Permissions: TYPO3 page or external URL Return Parameter for Login Page URL: URL query parameter of the login page without leading ? or &

Note: The parameter for the login page used by the extension "felogin" is return_url=###URL###.

URL Markers

The return parameter of the URL supports marker substitution.

Marker Description
###URL### current URL (URL encoded)
###URL_BASE64### current URL base64 encoded (URL encoded)
###ISO_639-1### current language as two letter ISO code (ISO 639-1)
###IETF_BCP47### current language as IETF language tag (IETF BCP 47, RFC 5646/4646/3066/1766) aka "hreflang"


  • 0.4.2 PHP 8.1 compatible release
  • 0.4.1 Prevent exception when language not available from request
  • 0.4.0
    • Error pages are cached in TYPO3's page cache
    • Set as compatible with v11 LTS
  • 0.3.8 Add extension-key to composer.json
  • 0.3.7 Prevent 403 handler from getting caught in a loop
  • 0.3.6 Prevent 404 handler from getting caught in a loop
  • 0.3.5 Don't fetch error page twice
  • 0.3.4 Set as compatible with v10 LTS
  • 0.3.3
    • Add fallbacks for missing error content
    • Do not throw exceptions in case of configuration errors by default
  • 0.3.2 Add eot, ttf and woff/woff2 to the list of web resources
  • 0.3.0 Show error page for 404 status; send only a small 404 response for missing web resources
  • 0.2.0 Show error page on missing permission for current login
  • 0.1.0 Redirect to login page