The current system:
* A script hosted & maintained by a member of the WMF sends impression data as an email every 15 minutes. For this to work, we need to check "Use legacy impression counting" in CentralNotice.
* Our FetchImpression script receives and processes the mails and writes the data into a database table. Problems in this process:
* Transport method (IMAP) needs to be a PHP module
* To map the banner names (page names on meta) in the impression mails to tracking keywords, the code in `Banner.php` requests the banner code from metawiki and parses it, looking for keyword parameters. If a banner name is mapped to keywords once, it's never mapped again, even when the keyword changes. However, the request to metawiki is done on every run of the script.
Goal: Find a better way to get the analysis value of "donation per impression/donation quota".