Why is an on-prem gateway necessary for WEB URL refreshes?

[edhans]

I just added a web url to a PBI report that was only using Sharepoint. It took me a while to figure out how to get it to refresh - turns out I had to add a data source to my on prem gateway for a specific URL. What is the logic of that?

[v-yuezhe-msft · Accepted solution]

@edhans,

What is your web source? As per this article,  if you are using the Web.Page function, you do need a gateway if you have republished the dataset or your report after November 18th, 2016.

Once a data source in your dataset requires gateway to refresh, the whole dataset requires gateway.

Regards,
Lydia

[edhans]

It is a publically available web page. I see that note now for Nov 2016 and forward. I guess I just don't understand the logic of requiring the report to go from the PBI Service to my gateway which goes out to the internet to pull the data, then send it back to the gateway which sends it back to the PBI Service.

Seems the long way around. Much like Sharepoint access doesn't require a gateway. The PBI service just grabs it since it is on the internet.