Modify WP database via standalone script

I want to add a standalone php script on my server which modifies the WordPress database. This script would be called directly from an external system.

For example if I wanted to approve any comment made by user “Steve_Jobs”, I could look this up in the wp_comments table and set the comment_approved field to “1”.

That may or may not work. Looking at the wp_set_comment_status function in comment.php I doubt it would work. That function does the same UPDATE sql statement I would of done, but it does other stuff like clean the comment cache and update the comment count.

So calling wp_set_comment_status() to do the job might be better than messing with the database directly. I see the function depends on other things in the WordPress setup like the global $wpdb object and other functions. Which WordPress files do I need to include in my standalone script to keep things happy? i.e. which “require_once” statements do i need in order to make use of WordPress functions in a standalone script?

Not sure if I should be doing this as a WordPress plugin instead, because I’m not integrating anything into the blog as such. Nothing is being displayed in the blog theme and there’s no user interaction. It’s just a standalone script invoked by an external system.

What I’m actually trying to do is only allow valid usernames to post comments. Integration is tricky because my WordPress blog can’t access the user database of the external system. So the best I can do is get the external system to call a webpage (supplying any info needed) which validates the feedback.

One way could involve the following steps:

1) User visits blog and submits feedback. They are asked to enter the same username which they use in the external system (no way to verify this at this stage).

2) When the blog page refreshes, instead of saying “Your comment is awaiting moderation” next to their feedback, it asks them to click something in the external system to activate their feedback.

3) They click something in the external system which then automatically calls my php script. For example it would load myserver.com/verify_feedback.php?user=Steve_Jobs

4) The php script looks up Steve_Jobs in the wp_comments table and sets comment_approved to “1”. Or more ideally calls wp_set_comment_status() to update this field instead.

Actually even better (And I’m a WordPress noob so not sure if its possible) would be the following…

1) User visits blog via external system, and their valid username is passed at the same time. So I could add a stub/redirect page (or hack the WordPress file/theme) which takes the username from the URL and automatically registers them as a user of my WordPress blog. I would add extra info to the URL like a hash to prevent hacking. A WordPress cookie is stored, and they can freely leave blog comments with no comment verification needed. But I’m not sure if/how users are handled in WordPress. I see no “sign up” link for example. So I’m thinking the only users WordPress handles are admin?

By the way, the “external system” i refer to is some game software. Within the game its possible to both 1) load a webpage in the users default browser, and also 2) call a webpage directly (without user intervention and even without them knowing). In my first scenario I’d be making use of both those features. I only want registered users of the game software to be able to leave comments in my blog.

Thanks for any feedback/suggestions.