Modal iframe integration
When the CMP requires the user to provide consent, it will load the publisher provided config.uiUrl in an iframe. It will then post a message to the iframe with the following message format.
parameter: config, // includes the uiCustomParams from in the "init" command
The consent UI should listen for this message, then initialise the UI. Once the user has saved their consent, the consent UI should post a message back to the parent window with the following format.
returnValue: consentString, // bsee64 encoded consent string
success: boolean, // true if successful, otherwise false
callId: uniqueId // same uniqueId passed in the __cmpUICall message
Once the CMP receives the __cmpUIReturn message, it will destroy the iframe.
Standalone UI integration
When the CMP requires the user to provide consent, it will redirect to config.uiUrl with a redirect_url query parameter. Once the user has saved their consent, the UI should redirect back to the redirect_url passing an EuConsent query parameter with the value of the base64 consent string.