Data enrichment con Google Tag Manager server-side: enriquece el payload de tus hits de GA4 con el Promise API de GTM

//API's required for this client to work
const claimRequest = require('claimRequest');
const getRequestQueryParameter = require('getRequestQueryParameter');
const runContainer = require('runContainer');
const sendHttpGet = require('sendHttpGet');
const getRequestHeader = require('getRequestHeader');
const isRequestMpv2 = require('isRequestMpv2');
const extractEventsFromMpv2 = require('extractEventsFromMpv2');
const returnResponse = require('returnResponse');
const JSON = require('JSON');
const Object = require('Object');


const hostedJsonQueryString = getRequestQueryParameter('ep.'+ data.ga4Param);
const origin = getRequestHeader('Origin');

//Declare enrichGa4Stream variable and set it to false by default
let enrichGa4Stream = false;

//Generate an array with the GA4 hit params, doesn't matter if GET or POST request
const ga4EventParams = extractEventsFromMpv2();

//Declare eventObject variable
let eventObject;

//Populate the eventObject variable with the object contained in the ga4EventParams array
for(let i = 0; i < ga4EventParams.length; i++){
    
    eventObject = ga4EventParams[i];
      
}
      
//Generate an array with the keys contained in the eventObject object
const eventsKeys = Object.keys(eventObject);

//Run a for loop against the eventsKey array to look for the data.ga4Param    
for(var i = 0 ; i < eventsKeys.length ; i++){
    //Does the eventsKeys array contain the value of template field data.ga4Params? If 'yes', set enrichGa4Stream variable to true
    if(eventsKeys[i] === data.ga4Param){
          
        enrichGa4Stream = true;
          
    }
        
}

//Claim incoming request if all these conditions are met 
if(origin === data.origin && isRequestMpv2() && enrichGa4Stream === true ){

    claimRequest();
   
    //Variable containing the url to which the request is going to be sent
    const requestUrl = data.endpoint;
  
    //Necessary request headers  
    const requestHeaders = function(){
      //If endpoint requires authentication...
      if(data.apiAuthentication){
  
        return {
          headers: {'content-Type':'application/json', 'Authorization':'Bearer ' + data.bearerToken}
        }; 
    
      } 
      //...and if it doesn't
      else {
    
        return {
          headers: {'content-Type' : 'application/json'}
        };    
    
      }
  
    };

   //GET request that returns a promise: the server hosted dataLayer
  sendHttpGet(requestUrl,requestHeaders()).then((results => {
    
    //If promise comes back with a succesful response...  
    if(results.statusCode === 200){
    
    const dataLayer = JSON.parse(results.body);
    const dataLayerKeys = Object.keys(dataLayer);
    const dataLayerValues = Object.values(dataLayer);

    for(let i = 0; i < dataLayerKeys.length; i++){
      
    //If eventObject and dataLayer objects don't have keys that are named the same...
      
      if(!eventObject.hasOwnProperty(dataLayerKeys[i])){
    
      eventObject[dataLayerKeys[i]] = dataLayerValues[i];
      
      }
      //Otherwise, rename the property to be added to the already existing evenObject object concatenating a _ at the end
      else{
      
        let renamedKey = dataLayerKeys[i] + '_';
        eventObject[renamedKey] = dataLayerValues[i];
      
      }
          
    }
    
   //Run container  with eventObject 
   runContainer(eventObject, () => returnResponse());
   }
    
   //If promise comes back with a response other than 200, run a virtual instance of the container with the GA4 event data object alone
    
   else{
   
   runContainer(eventObject, () => returnResponse());
   
   }

  }));
   
}