Hi Patrick!
Thank you for you attention and answer.
Let me expand a lit bit more my needs just to see if you can supply me an extra help.
What I'm doing is automatically get the total number of datasets of many ArcGIS Open Data instances/installations. I only know beforehand the customer's domain (what comes before *.opendata.arcgis.com). So I can't go manually to each customer's instance/installation to check 'owner' attribute. So it came to my mind to rely on the customer ID (I think what comes before *.opendata.arcgis.com) to be a filter choice. I realized that the example I gave before (filter[url]) was not a good choice, as URL attribute doesn't see to be consistent across different instances/installations according to customer ID.
In sum, is there a way to return all datasets of an instance/installation given only the customer ID (what comes before *.opendata.arcgis.com)?
Thank you,