Q:

Retrieving Redmine issues via API for several projects and trackers

I would like to retrieve all Redmine issues that belong to a list of projects, and have either one of three trackers.
I was hoping to use query parameters project_id and tracker_id with multiple values. I tried tracker_id=3,1,5 and tracker_id=[1,3,5] as well as tracker_id=1&tracker_id=3&tracker_id=5 (and similar for project_id) but none of them will work. 
The API page (http://www.redmine.org/projects/redmine/wiki/Rest_Issues) doesn't give any indication that it's possible.  This might mean that I'd have to make a large number of API calls which may be hard to maintain ...
Any help or pointers are appreciated.

A:

You need to use | instead of , character.
http://www.redmine.org/projects/redmine/issues.xml?tracker_id=1|2
source: https://github.com/redmine/redmine/blob/edbc9611de355e7933793b1eb155474d88d46fbd/app/models/query.rb#L621

