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Google Tag Manager

The Braze Swift SDK can be initialized and controlled by tags configured within Google Tag Manager.

As a prerequisite for this implementation, your Swift SDK integration must be complete.

Configuring your Google Tag Manager

In this example, we’ll pretend we are a music streaming app that wants to log different events as users listen to songs. Using Google Tag Manager for iOS, we can control which of our third-party vendors receive this event and create tags specific to Braze.

Custom events

Custom events are logged with actionType set to logEvent. The Braze custom tag provider in our example is expecting the custom event name to be set using eventName.

To get started, create a trigger that looks for an eventName that equals played song.

A custom trigger in Google Tag Manager set to trigger for some events when "eventName" equals "played song".

Next, create a new Tag (“Function Call”) and enter the class path of your custom tag provider described later in this article.

This tag will be triggered when you log the played song event we just created.

In our example tag’s custom parameters (key-value pairs), we’ve set eventName to played song—which will be the custom event name logged to Braze.

A tag in Google Tag Manager with classpath and key-value pair fields. This tag is set to trigger with the previously created "played song" trigger.

You can also include additional key-value pair arguments to the tag, which will be sent as custom event properties to Braze. eventName and actionType will not be ignored for custom event properties. In the following example tag, we’ll pass in genre, which was defined using a tag variable in Google Tag Manager - sourced from the custom event we logged in our app.

The genre event property is sent to Google Tag Manager as a “Firebase - Event Parameter” variable since Google Tag Manager for iOS uses Firebase as the data layer.

A variable in Google Tag Manager where "genre" is added as an event parameter for the "Braze - Played Song Event" tag.

Lastly, when a user plays a song in our app, we will log an event through Firebase and Google Tag Manager using the Firebase analytics event name that matches our tag’s trigger name, played song:

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let parameters: [String: Any] = ["genre": "pop",
                                 "number of times listened": 42]
Analytics.logEvent("played song", parameters: parameters)

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NSDictionary *parameters = @{@"genre" : @"pop",
                             @"number of times listened" : @42};
[FIRAnalytics logEventWithName:@"played song" parameters:parameters];

Logging custom attributes

Custom attributes are set via an actionType set to customAttribute. The Braze custom tag provider is expecting the custom attribute key-value to be set via customAttributeKey and customAttributeValue:

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let parameters: [String: Any] = ["customAttributeKey": "favoriteSong",
                                 "customAttributeValue": "Private Eyes"]
FIRAnalytics.logEvent(withName:"customAttribute", parameters: parameters)

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NSDictionary *parameters = @{@"customAttributeKey" : @"favoriteSong",
                             @"customAttributeValue" : @"Private Eyes"};
[FIRAnalytics logEventWithName:@"customAttribute" parameters:parameters];

Calling changeUser

Calls to changeUser() are made via an actionType set to changeUser. The Braze custom tag provider is expecting the Braze user ID to be set via an externalUserId key-value pair within your tag:

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let parameters: [String: Any] = ["externalUserId": "favorite userId"]
Analytics.logEvent(withName:"changeUser", parameters: parameters)

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NSDictionary *parameters = @{@"externalUserId" : userId};
[FIRAnalytics logEventWithName:@"changeUser" parameters:parameters];

Braze SDK custom tag provider

With the tags and triggers set up, you will also need to implement Google Tag Manager in your iOS app which can be found in Google’s documentation.

Once Google Tag Manager is installed in your app, add a custom tag provider to call Braze SDK methods based on the tags you’ve configured within Google Tag Manager.

Be sure to note the “Class Path” to the file - this is what you’ll enter when setting up a tag in the Google Tag Manager console.

This example shows one of many ways to structure your custom tag provider, where we determine which Braze SDK method to call based on the actionType key-value pair sent down from Google Tag Manager. This example assumes you’ve assigned the Braze instance as a variable in the AppDelegate.

The actionType we’ve supported in our example are logEvent, customAttribute, and changeUser, but you may prefer to change how your tag provider handles data from Google Tag Manager.

Add the following code to your BrazeGTMTagManager.swift file.

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import FirebaseAnalytics
import GoogleTagManager
import BrazeKit

let ActionTypeKey: String = "actionType"

// Custom Events
let LogEventAction: String = "logEvent"
let LogEventName: String = "eventName"

// Custom Attributes
let CustomAttributeAction: String = "customAttribute"
let CustomAttributeKey: String = "customAttributeKey"
let CustomAttributeValueKey: String = "customAttributeValue"

// Change User
let ChangeUserAction: String = "changeUser"
let ChangeUserExternalUserId: String = "externalUserId"

@objc(BrazeGTMTagManager)
final class BrazeGTMTagManager : NSObject, TAGCustomFunction {
  @objc func execute(withParameters parameters: [AnyHashable : Any]!) -> NSObject! {
    var parameters: [String : Any] = parameters as! [String : Any]
    guard let actionType: String = parameters[ActionTypeKey] as? String else {
      print("There is no Braze action type key in this call. Doing nothing.")
      return nil
    }
    parameters.removeValue(forKey: ActionTypeKey)
    if actionType == LogEventAction {
      logEvent(parameters: parameters)
    } else if actionType == CustomAttributeAction {
      logCustomAttribute(parameters: parameters)
    } else if actionType == ChangeUserAction {
      changeUser(parameters: parameters)
    }
    return nil
  }
  
  func logEvent(parameters: [String : Any]) {
    var parameters: [String : Any] = parameters
    guard let eventName: String = parameters[LogEventName] as? String else { return }
    parameters.removeValue(forKey: LogEventName)
    AppDelegate.braze?.logCustomEvent(name: eventName, properties: parameters)
  }
  
  func logCustomAttribute(parameters: [String: Any]) {
    guard let customAttributeKey = parameters[CustomAttributeKey] as? String else { return }
    let customAttributeValue = parameters[CustomAttributeValueKey]
    
    if let customAttributeValue = customAttributeValue as? String {
      AppDelegate.braze?.user.setCustomAttribute(key: customAttributeKey, value: customAttributeValue)
    } else if let customAttributeValue = customAttributeValue as? Date {
      AppDelegate.braze?.user.setCustomAttribute(key: customAttributeKey, value: customAttributeValue)
    } else if let customAttributeValue = customAttributeValue as? Double {
      AppDelegate.braze?.user.setCustomAttribute(key: customAttributeKey, value: customAttributeValue)
    } else if let customAttributeValue = customAttributeValue as? Bool {
      AppDelegate.braze?.user.setCustomAttribute(key: customAttributeKey, value: customAttributeValue)
    } else if let customAttributeValue = customAttributeValue as? Int {
      AppDelegate.braze?.user.setCustomAttribute(key: customAttributeKey, value: customAttributeValue)
    } else if let customAttibuteValue = customAttributeValue as? [String] {
      AppDelegate.braze?.user.setCustomAttributeArray(key: customAttributeKey, array: customAttibuteValue)
    }
  }
  
  func changeUser(parameters: [String: Any]) {
    guard let userId = parameters[ChangeUserExternalUserId] as? String else { return }
    AppDelegate.braze?.changeUser(userId: userId)
  }
}

Add the following code to your BrazeGTMTagManager.h file:

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@import Firebase;
@import GoogleTagManager;

@interface BrazeGTMTagManager : NSObject <TAGCustomFunction>

@end

And add the following code to your BrazeGTMTagManager.m file:

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#import <Foundation/Foundation.h>
#import "BrazeGTMTagManager.h"
#import "BrazeKit"
#import "AppDelegate.h"

static NSString *const ActionTypeKey = @"actionType";

// Custom Events
static NSString *const LogEventAction = @"logEvent";
static NSString *const LogEventEventName = @"eventName";

// Custom Attributes
static NSString *const CustomAttributeAction = @"customAttribute";
static NSString *const CustomAttributeKey = @"customAttributeKey";
static NSString *const CustomAttributeValueKey = @"customAttributeValue";

// Change User
static NSString *const ChangeUserAction = @"changeUser";
static NSString *const ChangeUserExternalUserId = @"externalUserId";

@implementation BrazeGTMTagManager

- (NSObject *)executeWithParameters:(NSDictionary *)parameters {
  NSMutableDictionary *mutableParameters = [parameters mutableCopy];
  
  NSString *actionType = mutableParameters[ActionTypeKey];
  if (!actionType) {
    NSLog(@"There is no Braze action type key in this call. Doing nothing.", nil);
    return nil;
  }
  
  [mutableParameters removeObjectForKey:ActionTypeKey];
  
  if ([actionType isEqualToString:LogEventAction]) {
    [self logEvent:mutableParameters];
  } else if ([actionType isEqualToString:CustomAttributeAction]) {
    [self logCustomAttribute:mutableParameters];
  } else if ([actionType isEqualToString:ChangeUserAction]) {
    [self changeUser:mutableParameters];
  } else {
    NSLog(@"Invalid action type. Doing nothing.");
  }
  return nil;
}

- (void)logEvent:(NSMutableDictionary *)parameters {
  NSString *eventName = parameters[LogEventEventName];
  [parameters removeObjectForKey:LogEventEventName];
  [AppDelegate.braze logCustomEvent:eventName
                         properties:parameters];
}

- (void)logCustomAttribute:(NSMutableDictionary *)parameters {
  NSString *customAttributeKey = parameters[CustomAttributeKey];
  id customAttributeValue = parameters[CustomAttributeValueKey];
  
  if ([customAttributeValue isKindOfClass:[NSString class]]) {
    [AppDelegate.braze logCustomEvent:customAttributeKey
                           properties:parameters];
  } else if ([customAttributeValue isKindOfClass:[NSDate class]]) {
    [AppDelegate.braze.user setCustomAttributeWithKey:customAttributeKey
                                            dateValue:customAttributeValue];
  } else if ([customAttributeValue isKindOfClass:[NSNumber class]]) {
    if (strcmp([customAttributeValue objCType], [@(YES) objCType]) == 0) {
      [AppDelegate.braze.user setCustomAttributeWithKey:customAttributeKey
                                              boolValue:[(NSNumber *)customAttributeValue boolValue]];
    } else if (strcmp([customAttributeValue objCType], @encode(short)) == 0 ||
               strcmp([customAttributeValue objCType], @encode(int)) == 0 ||
               strcmp([customAttributeValue objCType], @encode(long)) == 0) {
      [AppDelegate.braze.user setCustomAttributeWithKey:customAttributeKey
                                               intValue:[(NSNumber *)customAttributeValue integerValue]];
    } else if (strcmp([customAttributeValue objCType], @encode(float)) == 0 ||
               strcmp([customAttributeValue objCType], @encode(double)) == 0) {
      [AppDelegate.braze.user setCustomAttributeWithKey:customAttributeKey
                                            doubleValue:[(NSNumber *)customAttributeValue doubleValue]];
    } else {
      NSLog(@"Could not map NSNumber value to Braze custom attribute:%@", customAttributeValue);
    }
  } else if ([customAttributeValue isKindOfClass:[NSArray class]]) {
    [AppDelegate.braze.user setCustomAttributeArrayWithKey:customAttributeKey
                                                     array:customAttributeValue];
  }
}

- (void)changeUser:(NSMutableDictionary *)parameters {
  NSString *userId = parameters[ChangeUserExternalUserId];
  [AppDelegate.braze changeUser:userId];
}

@end
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