Here is a patch [[tag patch]] to add a *forward*ing functionality
to the [[`meta`_plugin|plugins/meta]].

Find the most recent version at
<http://www.schwinge.homeip.net/~thomas/tmp/meta_forward.patch>.

I can't use `scrub(...)`, as that will strip out the forwarding HTML command.
How to deal with that?

I can also submit a Git patch, if desired.


# Syntax

**URL** = http://some.nice/place/ (*etc.*)

**WHITHER** = \[\[**[[wikilink]]**]] | **URL**

**D** = natural number (*meaning seconds*)

**OPT_DELAY** = delay=**D** | empty (*immediatelly*)

\[[meta forward="**WHITHER**" **OPT_DELAY**]]


# Extensions and Ideas

It might be doable to add references to pages that refer to the page containg
the forwarding statement also to the referred-to page.

--[[tschwinge]]


# Discussion

> The html scrubber cannot scrub meta headers. So if you emit one
> containing user-supplied data, it's up to you to scrub it to avoid all
> possible XSS attacks. Two attacks I'd worry about are cyclic meta refresh
> loops, which some, but not all web browsers detect and break, and any way
> to insert javascript via the user-supplied parameters. (Ie, putting
> something in the delay value that closes the tag can probably insert
> javascript ATM; and are there ways to embed javascript in the url?)
> --[[Joey]]

>> OK.  I can add code to make sure that `$delay` **D** indeed is a natural number
>> and that the passed target address **WHITHER** is nothing but a valid target address.
>> (How to qualify a valid target address?)
>> What is a *cyclic meta refresh loop*?  Two pages in turn forwarding to each other?
>> I think it would be possible to implement such a guard when only in-wiki links
>> ([[wikilink]]s) are being used, but how to do so for external links?  --[[tschwinge]]