How to use Amazon Polly in PHP to speak some text and save to mp3 file

texttospeech.php

<?php

try {

  // This should be gitignored. Define your API credentials in it. Get the credentials from AWS IAM. Should have full Polly permissions.
  require_once 'vendor/aws.config.php';
  
  // The official AWS SDK for PHP, version 3. See https://docs.aws.amazon.com/aws-sdk-php/v3/guide/getting-started/installation.html
  require_once "vendor/aws.phar";

  $speak_this = 'This is a php test of Polly';
  
  // Check that PHP has permission to create this file in the current directory.
  $filename = 'speech.mp3';

  $polly = new Aws\Polly\PollyClient([
    'region' => 'us-east-1',
    'version' => 'latest',
    'credentials' => [
      'key' => AWS_ACCESS_KEY_ID, // define this in vendor/aws.config.php
      'secret' => AWS_SECRET_ACCESS_KEY // define this in vendor/aws.config.php
    ]
  ]);

  $result = $polly->synthesizeSpeech([
    'OutputFormat' => 'mp3',
    'Text' => $speak_this,
    'TextType' => 'text',
    'VoiceId' => 'Russell'
  ]);
  
  echo 'file: <a href="' . $filename . '">' . $filename . '</a>';
  $saved = file_put_contents(__DIR__ . '/' . $filename, $result['AudioStream']->getContents());
  echo '<pre>bytes written: ' . var_export($saved, TRUE);

} catch(Exception $e) {
  var_export($e);
}