Google Consent Mode

Google Consent Mode allows web and app developers to adjust tag and app SDK behavior based on user consent choices. Google will be able to dynamically adapt the behavior of Google tags, Google Analytics, Google Ads, Floodlight and Conversion Linker. To accomplish this, consent types have been created to alter specific behavior in the aforementioned products.

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Platform support
GCM is supported for iOS and tvOS.

Consent types include:

Consent type	Description	Consent statuses
analytics_storage	Enables storage, such as cookies (web) or device identifiers (apps), related to analytics, for example, visit duration.	granted \| denied
ad_storage	Enables storage, such as cookies (web) or device identifiers (apps), related to advertising.	granted \| denied
ad_user_data	Sets consent for sending user data to Google for online advertising purposes.	granted \| denied
ad_personalization	Sets consent for personalized advertising.	granted \| denied

More information here: https://support.google.com/google-ads/answer/10000067?hl=en

Setting up Google Consent Mode (GCM) for iOS/tvOS

Enable Google Consent Mode in your geolocation rules and map categories from the OneTrust CMP to Google storage types.
Ensure the supported Google products (e.g. Firebase) have been installed on the app already.

Set the default consent values for GCM in your app's info.plist. Value can be set to true or false.

<key>GOOGLE_ANALYTICS_DEFAULT_ALLOW_ANALYTICS_STORAGE</key> <false/>
<key>GOOGLE_ANALYTICS_DEFAULT_ALLOW_AD_STORAGE</key> <false/>
<key>GOOGLE_ANALYTICS_DEFAULT_ALLOW_AD_USER_DATA</key> <false/>
<key>GOOGLE_ANALYTICS_DEFAULT_ALLOW_AD_PERSONALIZATION_SIGNALS</key> <false/>

Query for Google Consent Mode consent statuses from the OneTrust SDK. getOTGoogleConsentModeData() will return an object containing the current status and values for each of the Google Consent types based on the mapping done in Step 1.

OTPublishersHeadlessSDK.shared.getOTGoogleConsentModeData().otSDKStatus
OTPublishersHeadlessSDK.shared.getOTGoogleConsentModeData().consentType

Status type	Description
notInitialized	Application calls method before a successful SDK initialization (at least once). Consent has not been collected.
notConsented	Application calls method before user interacts with and dismisses the banner. Consent has not been collected.
consented	Application calls method after user has interacted with the banner. Consent has been collected.

Consent type	Description
unassigned	'Do not Assign Category' was mapped to this storage/consent type in the geolocation rules.
undefined	The SDK was not initialized successfully at least once, data was not fetched, or the mapped category does not exist (no SDKs assigned).
denied	Consent is rejected/withdrawn for the associated category.
granted	Consent is given/provided to associated category.

Sample Response:

//consent interaction status
OneTrust GCM SDK status: consented

//consent value of each storage type
OTGoogleConsentType(
  analyticsStorage: OTPublishersHeadlessSDK.OTGoogleConsentMode.granted, 
  adStorage: OTPublishersHeadlessSDK.OTGoogleConsentMode.granted, 
  adUserData: OTPublishersHeadlessSDK.OTGoogleConsentMode.granted, 
  adPersonalization: OTPublishersHeadlessSDK.OTGoogleConsentMode.granted)

Update the desired Google library from the consent retrieved in Step 5 with the setConsent() public method from Google.

Analytics.setConsent([
.analyticsStorage: .granted,
.adStorage: .granted,
.adUserData: .granted,
.adPersonalization: .granted,
])

As the application will need to retrieve the consents for each Consent type and set it in the Google library as indicated in steps 4 and 5, OneTrust has written a function to assist with and simplify the process:

func handleGoogleConsentMode() {
    let gcmOTData = OTPublishersHeadlessSDK.shared.getOTGoogleConsentModeData()
    #if canImport(FirebaseAnalytics)
    Analytics.setConsent([
        .adStorage: gcmOTData.consentType.adStorage == .granted ? .granted : .denied,
        .analyticsStorage: gcmOTData.consentType.analyticsStorage == .granted ? .granted : .denied,
        .adUserData: gcmOTData.consentType.adUserData == .granted ? .granted : .denied,
        .adPersonalization: gcmOTData.consentType.adPersonalization == .granted ? .granted : .denied,
    ])
    #endif
}

OneTrust recommends calling the handleGoogleConsentMode() function above when the OTConsentUpdated broadcast is triggered. OTConsentUpdated is triggered every time any OneTrust UI is dismissed. More info on that method here.
```
NotificationCenter.default.addObserver(self,
    selector: #selector(returnConsentOTConsentUpdated(_:)),
    name: Notification.Name("OTConsentUpdated"),
    object: nil)

@objc func returnConsentOTConsentUpdated(_ notification:Notification){
    handleGoogleConsentMode()
}
```
Alternatively, you can also use UI Interaction Events instead of broadcast receivers to know when to call handleGoogleConsentMode(). Reference this page for more information.

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Additional Information
You can view more information regarding consent mode setup here: https://developers.google.com/tag-platform/security/guides/app-consent?platform=ios&consentmode=advanced

Verifying consent settings

You can verify that your consent settings are working as intended by viewing the Xcode debug console for your app.

Enable verbose logging on your device.
In the Xcode debug console, look for:
- analytics_storage
- ad_storage
- ad_user_data
- ad_personalization
For example, if Ad storage are enabled, you'll see the following message:
```
ad_storage is granted.
```