Drupal 7: Creating forum posts programmatically

I've been trying to create a drupal 7 module which requires programmatic creation of forum posts. I've used info from this question but I believe that info is not valid for drup开发者_如何学运维al 7 anymore, because I keep getting errors.

The forum post is being created. It can be accessed if I go directly to the url. But that post is not visible in the forum itself. When I checked the database I found that there is a table forum_index that is not being populated when creating forum post with that code. It is populated when creating the post manually.

Any ideas? I have searched everywhere for this. Here is a very similar question that remains unanswered. thanks for any help

Drupal7 forums are layed out like this:

Containers & Forums are Taxonomy Forum Topics are Nodes forum topic posts are comments

So do you need to know how to create topics(Nodes) or topic posts(Comments)?