Add 'hb_cache_host' and 'hb_cache_path' targeting for video bids when cache is set

[idettman]

Type of change

• Other

Description of change

When setConfig.cache.url is defined, pass hb_cache_host to ad server. We need hb_cache_host set to trigger the new Prebid video cache redirector, and we may as well send hb_cache_path as well. Both host and path are parsed from the prebid config cache property: config.getConfig('cache.url').

Use case:

1. The new Prebid Video Cache Redirector is live and the ad server URL points to it
2. video adunit calls for AppNexus and Rubicon video
3. AppNexus returns VAST and caches it client-side
4. On client side caching, hb_cache_host isn't sent to ad server

The general idea is straight-forward: when cache.url is specified, parse it and add hb_cache_host and hb_cache_path to the targeting variables.

config.setConfig({
  cache: {
    url: 'https://prebid.adnxs.com/pbc/v1/cache'
  }
});

[robertrmartinez]

So if mediaType is video,

And cache.url is defined,

Every bidResponse object will now contain hb_cache_host and hb_cache_path in the adServerTargeting.

Sounds good to me.

And if an adapter had also previously specified these two values in its bidResponseObject, then we take it as is instead of overriding with the client side cache.url.

This satisfies the scenario where some bidders use a server side cache and others use client side.

LGTM.

[robertrmartinez]

Nice idea!

[mkendall07]

can anyone explain or link to what the Prebid Video Cache Redirector is ? Thanks

[bretg]

can anyone explain or link to what the Prebid Video Cache Redirector is ? Thanks

https://github.com/prebid/prebid-video-cache-redirector/blob/master/motivation.md

[idettman]

@mkendall07

Prebid Cache Redirector Service

Git repo: https://github.com/prebid/prebid-video-cache-redirector
Motivation doc: https://github.com/prebid/prebid-video-cache-redirector/blob/master/motivation.md

DFP imposes a limit on publishers entering in a video VAST tag URL... the host cannot be a variable.
Given that macros are possible, it seems like a good solution would be to supply the host and path on the ad request, but this is impossible in DFP, as %% macros cannot be supplied in the host name.

The solution we chose is for Prebid.org to host a cache redirector service. The video creative would point to this service, which then redirects the player to where the cached asset actually resides.
The publisher would be able to enter a constant VAST tag URL like:

https://cache.prebid.org/redir?uuid=%%PATTERN:hb_uuid%%&host=%%PATTERN:hb_cache_host%%

cache.prebid.org is the new service -- it looks at the hb_cache_host variable and redirects the video player to the appropriate place, e.g. prebid.adnxs.com/pbc/v1/cache or prebid-server.rubiconproject.com/cache.

To support the use case of separate line items for each bidder, the VAST tag URL could contain the bidder-specific key-value-pairs:

https://cache.prebid.org/redir?uuid=%%PATTERN:hb_uuid_rubicon%%&host=%%PATTERN:hb_cache_host_rubicon%%