Using the AWS PHP SDK to upload files to S3 bucket using EC2 Instance Profile (IAM Role) Credentials

putObject.php

<?php
require_once 'vendor/autoload.php';

use Aws\Credentials\CredentialProvider;
use Aws\S3\S3Client;

$provider = CredentialProvider::instanceProfile();
$mprovider = CredentialProvider::memoize($provider);

$s3 = new S3Client([
    'region' => 'us-east-1',
    'version' => 'latest',
    'credentials' => $mprovider
]);

$data = [
    'Bucket' => 'my-s3-bucket',
    'Key'    => 'path/to/upload/file/to.txt',
    'Body'   => 'Hello, S3.',
    'ACL'    => 'public-read'
];

$result = $s3->putObject($data);

print_r($result);