FirebaseStorageUpload.js

const admin = require('firebase-admin');
admin.initializeApp({
 credential: admin.credential.applicationDefault(),
 storageBucket: "YOUR STORAGE BUCKET URL HERE"
});
const settings = { timestampsInSnapshots: true}; 
const db = admin.firestore();
db.settings(settings);
const bucket = admin.storage().bucket();


function uploadFile(file, token){
  	return new Promise((resolve, reject)=> {
    	const metadata = {
          metadata: {
            firebaseStorageDownloadTokens: token
          },
          contentType: 'image/png',
          cacheControl: 'public, max-age=31536000',
        };

         bucket.upload(file, {
          gzip: true,
          metadata: metadata,
          destination: `images/${token}`
        }, function(err, file) {
            if(err){
              console.log(err);
              reject(err)
            } else {
              resolve({
                fileName: file.name,
                token: token
              });
            }
        });
    });
  }
  
  
  function handleImageReceived(agent){
    const fileUrl = agent.parameters.url;
    const token = Date.now()
    return uploadFile(fileUrl, token)
    .then(res => {
        agent.add("Image uploaded");   
    })
    .catch(error => console.log(error));
  }