Input requested from MultiLink users

This post relates to MultiLink and more specifically to the issue at http://drupal.org/node/796822

As I'm trying to plan a D7 version and would like to finalise functionality, I'd like to get some input from users here (rather than the issue queue, so as to reach a wider audience and maybe use a poll here.)

So, the big issue is to establish the "correct" way sending the user to a suitable page, considering both site language and content language, and trying to choose the "best" combination based on user language preferences.

I'll try to choose meaningful names for the two languages we deal with:

PCL - Preferred Content Language - the language of the content (typically a node) which ML will link to (or redirect) to.
PSL - Preferred Site Language - the language for the site user interface (menus, login form, etc.)

So, in general ML will link/redirect to: www.site.com/PSL/node/123 - where node/123 is in language PCL.

A couple of "rules":

1. ML should never change PSL. The only time PSL should change is when the user specifically requests a different language (e.g. via a "language switcher" menu/block.) Provide exceptions for special roles (admins, translation staff.)

2. ML should respect user's language preferences (multiple) from the Browser when choosing PCL. So in general, link/redirect to content in the first preferred language (if available, but if not, second preferred language, etc.)

External links

One question is what to do when the user arrives at the site from an external link. We can detect an external link by looking at the HTTP referrer.

• So, let's say the user found on Google: www.site.com/en/node/123 ... but preferred language (from browser) is French and node/123 has a French translation at node/124. Should ML-Redirect send them to fr/node/124 ? That is what would happen with the current version, but it breaks rule (1) above - we should display a message asking the user to confirm that they want to switch to French.

• Similarly, if node/123 is not available in French, we can redirect to fr/node/123 (i.e. site in French, content in English) but again should get confirmation from the user.

Internal links

Should behaviour be any different when dealing with internal links? Links generated with ML should already be ·"correct", but some pages may display links such as en/node/123 which ML-Redirect thinks should go to fr/node/123 or fr/node/124. Maybe ML should never redirect internal links? Or again, get confirmation from the user.

So, a message to get confirmation from the user should help in many cases. However, it might start to get annoying if it appears too often. This could be solved by a "always do this (don't ask again)" option, set for the current session.

Ok, these are all just thoughts and ideas, not a plan - I welcome further input.