formfill.php

<?php
// You'll need to use composer to install "symfony/browser-kit", "symfony/http-client" and "symfony/mime"
// Bring in the browserkit library
require_once( 'vendor/autoload.php' );
use Symfony\Component\BrowserKit\HttpBrowser;
use Symfony\Component\HttpClient\HttpClient;

// Make the galaxy form call our upload function when it's completed
add_action( 'gform_after_submission', 'post_to_third_party', 10, 2 );

function post_to_third_party( $entry, $form ) {  
  // Create our virtual browser
  $client = new HttpBrowser(HttpClient::create());

  // Load the form from zen planner
  $crawler = $client->request('GET', 'https://attteamlima.sites.zenplanner.com/prospect.cfm?programId=F5E46971-D514-4935-A231-C3439DA2C9D4&frame=true');    

  // Send the entries from the galaxy form to the zen form
  $client->submitForm('Submit Form', [  
    'FirstName' => rgar( $entry, '1.3' ),
    'LastName' => rgar( $entry, '1.6' ), 
    'PrimaryEmail' => rgar( $entry, '2' ),
    'PrimaryPhone' => rgar( $entry, '3' ),
    'Custom02' => rgar( $entry, '4' )
  ]);  
}
?>