Partner user syncs not called for OpenRTB endpoint in prebid server adapter

[haohany]

Type of issue

bug?

Description

Partner user sync are called when interpreting the legacy response: https://github.com/prebid/Prebid.js/blob/master/modules/prebidServerBidAdapter.js#L341-L347
However, this functionality doesn't exist in the new OpenRTB endpoint.
The sync rate of server-side partners will be hurt if publishers move to the new endpoint.

I'm happy to submit a PR if this is indeed an issue.

[dbemiller]

This may be because the /openrtb2/auction endpoint doesn't return the user syncs anywhere. It would need to be added there first.

But... we did discuss this, and didn't think it would hurt much (if at all) because Prebid.js should still be hitting the /cookie_sync endpoint and logging the syncs from there.

Nobody really knew why both /auction and /cookie_sync returned cookie syncs, and I didn't find any discussions about the design on github... so I assumed it was probably an accident of history and left it out of /openrtb2/auction.

I haven't heard any complaints from OpenRTB publishers yet... but if you migrate and find the sync rate to be much lower, I'd love to know about it!

[haohany]

@dbemiller I think you were talking about the sync between a partner and the prebid server. That part would be ok with the new endpoint as you mentioned.

The prebid user sync API recommends partners to define a registerSyncs function to drop their own pixels. But it's not called with the new endpoint. That would put the server-side partners at a disadvantage compared to the client-side counterparts.

[stale]

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