[_ck_]

It’s extremely easy to get forum <-> topic <-> post relationships in bbPress.

Depending on where you are, you may just be able to do a

global $topic,$bb_post;

Then $topic or $bb_post will have the following objects inside:

$bb_post

post_id

forum_id

topic_id

poster_id

post_text

post_time

poster_ip

post_status

post_position

$topic

topic_id

topic_title

topic_slug

topic_poster

topic_poster_name

topic_last_poster

topic_last_poster_name

topic_start_time

topic_time

forum_id

topic_status

topic_open

topic_last_post_id

topic_sticky

topic_posts

tag_count

You use it like this:

global $topic; echo "$topic->topic_title";

or to answer your original question:

global $bb_post; echo "$bb_post->forum_id";

Of course doing it this way bypasses any filters that may be in place from plugins but that may not matter if you are just trying to do something simple.