I use trackLink(sourceUrl, linkType, customData) to get some data(customdata) for e-commerce.
It’s better to write a plugin, not modify or add some code of core scripts.
The hook “Tracker.Visit.isExcluded” is useful. It enable us to get the data at every pageview. I create a table ‘piwik_log_ecommerce’ to log these datas.
But there are some problems for this idea
I want to link these customData with the data in table “piwik_log_visit”, so ‘idvisit’ is necessary. Is there some method to do this whitout modify core code?
trackLink will make a visit(I post this problem before,you can see the detail herehttp://forum.piwik.org/index.php?showtopic=1263)