SafeFrames don't resize

[benjaminclot]

Describe the bug
When using SafeFrames, the GPT iFrame doesn't resize correctly and stays at 1x1.

To Reproduce
Steps to reproduce the behavior:

1. Take this example: http://prebid.org/dev-docs/examples/adunit-refresh.html (which, by the way, needs some updating to work)
2. Enable SafeFrames
3. Refresh the ad (I also enabled a first call and debug mode)
   Demo: https://adverline-gam.glitch.me/tests/safeframe.html

Expected behavior
The GPT SafeFrame should resize to match its content ad. Obviously, this problem doesn't occur with AdSense/AdX ads, which are also enabled. Some refreshes may be needed to have header bidding winning the auction.

Desktop/Smartphone

• OS: any
• Browser: any
• Version: any

Strangely
Some header bidding ads seem to work (very rare).

Temporary fix
Will cause bugs eventually.

pbjs.onEvent('bidWon', (bid) => {
  if (bid.mediaType === 'banner') {
    const slot = window.googletag.pubads().getSlots()
      .find(s => s.getSlotElementId() == bid.adUnitCode);
    const safeFrame = document.querySelector(`#google_ads_iframe_${slot.getSlotId().getId().replace(/(\.|\/)/g, '\\$1')}[data-is-safeframe="true"]`);

    if (safeFrame) {
      safeFrame.style.height = `${bid.height}px`;
      safeFrame.style.width = `${bid.width}px`;
    }
  }
});

[benjaminclot]

ping @jaiminpanchal27 @jsnellbaker @idettman @mkendall07

Can anybody comment on this? This is a critical bug at it effectively blocks the usage of SafeFrames (at least with GAM).

[benjaminclot]

Any input on this issue would be most welcome.

[jaiminpanchal27]

@benjaminclot Thanks for submitting the issue. I was able to reproduce the issue with the steps you shared. Basically Prebid's resize function isn't working as it should. I will put up a PR today.

[benjaminclot]

Fixed by this PR: prebid/Prebid.js#3988