Mngr: Mngr moved page ICT:Dashboard autopurge architecture to ICT:Wiki - Dashboard autopurge architecture without leaving a redirect

2026-05-14T16:46:01Z

Mngr moved page ICT:Dashboard autopurge architecture to ICT:Wiki - Dashboard autopurge architecture without leaving a redirect

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Mngr at 21:40, 14 February 2026

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Mngr: Created page with "= ICT: Dashboard Auto‑Purge Architecture = This page documents why dashboards in this wiki require an automatic purge after saving a Page Forms form, why several intuitive approaches fail, and why the final solution works reliably. It is written for future administrators and maintainers of the Costa Sano Research infrastructure. == 1. The Problem == Dashboards such as '''Dashboard:Place''' display data stored in Cargo tables. After saving a form, the updated Car..."

2026-02-14T21:36:08Z

Created page with "= ICT: Dashboard Auto‑Purge Architecture = This page documents why dashboards in this wiki require an automatic purge after saving a Page Forms form, why several intuitive approaches fail, and why the final solution works reliably. It is written for future administrators and maintainers of the Costa Sano Research infrastructure. == 1. The Problem == Dashboards such as '''Dashboard:Place''' display data stored in Cargo tables. After saving a form, the updated Car..."

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= ICT: Dashboard Auto‑Purge Architecture =

This page documents why dashboards in this wiki require an automatic purge after saving a Page Forms form, why several intuitive approaches fail, and why the final solution works reliably.
It is written for future administrators and maintainers of the Costa Sano Research infrastructure.

== 1. The Problem ==

Dashboards such as '''Dashboard:Place''' display data stored in Cargo tables.
After saving a form, the updated Cargo data does not appear immediately because:

* Cargo updates are asynchronous
* MediaWiki caches parser output
* APCu/object cache may serve stale HTML
* Reverse proxies may cache responses
* Page Forms redirects do not trigger a purge

Users therefore see outdated dashboard data unless the page is manually purged.

A reliable, automatic purge mechanism is required.

== 2. Why Simple Solutions Do Not Work ==

=== 2.1. HTML <meta> refresh ===
MediaWiki sanitizes <meta> tags, even inside <code><nowiki>#tag:html</nowiki></code>.
The tag is displayed as text and never executed.

'''Conclusion:''' HTML refresh cannot be used.

---

=== 2.2. Redirecting to <code>?action=purge</code> ===
A redirect to:

<code>?action=purge</code>

always triggers MediaWiki’s confirmation dialog:

> Do you want to purge this page?

This dialog cannot be suppressed via GET requests.

'''Conclusion:''' GET‑based purge is never silent.

---

=== 2.3. Page Forms limitations ===
Page Forms does not provide:

* after‑save hooks
* post‑redirect callbacks
* purge triggers
* button overrides

There is no way to attach purge logic to the Save button.

'''Conclusion:''' Page Forms cannot trigger a purge.

---

=== 2.4. JavaScript redirect loops ===
If JavaScript redirects to <code>?action=purge</code>:

# The purge dialog appears
# After confirmation, the page reloads
# The JS sees no marker indicating purge completion
# JS redirects again
# Infinite loop

'''Conclusion:''' Redirect‑based purge is unstable.

---

=== 2.5. Query parameters being stripped ===
Reverse proxies, skins, and canonical URL rewrites may strip unknown parameters such as:

<code>?purged=1</code>

This causes loops because the JS cannot detect that the purge already happened.

'''Conclusion:''' Only parameters MediaWiki preserves can be used as markers.

== 3. Requirements for a Working Solution ==

A correct solution must:

* purge silently (no dialog)
* avoid loops
* work for all dashboards
* survive reverse proxies and canonicalization
* be centralized
* be successor‑friendly

This leads to the final architecture.

== 4. The Final, Working Solution ==

=== 4.1. Purge via the MediaWiki API ===
MediaWiki performs a silent purge only when:

* the request is a POST
* it includes a valid CSRF token
* it uses the API module

This avoids the confirmation dialog entirely.

---

=== 4.2. Use a preserved query parameter ===
MediaWiki never strips parameters beginning with <code>mw_</code>.
We use:

<code>?mw_purged=1</code>

to mark that the purge has already occurred.

---

=== 4.3. Centralize logic in <code>MediaWiki:Common.js</code> ===
This ensures:

* all dashboards benefit
* no per‑page hacks
* predictable behaviour

== 5. The Working Code (Common.js) ==

<syntaxhighlight lang="javascript">
$(function () {
const title = mw.config.get('wgPageName');

if (title && title.startsWith('Dashboard:')) {

// Only purge once
if (!location.search.includes('mw_purged=1')) {

new mw.Api().get({
action: 'query',
meta: 'tokens',
type: 'csrf'
}).done(function (data) {

const token = data.query.tokens.csrftoken;

new mw.Api().post({
action: 'purge',
titles: title,
token: token
}).always(function () {

// Reload the dashboard normally, marked as purged
const url = mw.util.getUrl(title, { mw_purged: 1 });
location.replace(url);
});
});
}
}
});
</syntaxhighlight>

== 6. Why This Works ==

=== Silent purge ===
* API POST + CSRF token
* No confirmation dialog
* No user interaction

=== No loops ===
* <code>mw_purged=1</code> is preserved by MediaWiki
* JS sees the marker and does not purge again

=== Works for all dashboards ===
* Uses <code>wgPageName</code>
* No hardcoded page names

=== Infrastructure‑safe ===
* Survives reverse proxies
* Survives canonical URL rewrites
* Survives short URLs
* Survives caching layers

=== Successor‑friendly ===
* One central rule
* No per‑page code
* Easy to understand and maintain

== 7. Summary ==

The final solution works because it respects all of MediaWiki’s constraints:

* Purge must be done via API POST
* CSRF token is required
* GET purge always shows a dialog
* Page Forms cannot trigger purge
* Unknown query parameters may be stripped
* Only <code>mw_*</code> parameters survive reliably

By combining these insights, we achieve a stable, silent, automatic purge mechanism for all dashboards.

ICT:Wiki - Dashboard autopurge architecture - Revision history

Mngr: Mngr moved page ICT:Dashboard autopurge architecture to ICT:Wiki - Dashboard autopurge architecture without leaving a redirect

Mngr at 21:40, 14 February 2026

Mngr at 21:38, 14 February 2026