Download/Upload files with Guzzle.

download.php

<?php

$client = new GuzzleHttp\Client();

// Ref: https://guzzle.readthedocs.io/en/latest/request-options.html#sink-option
$client->request('GET', 'http://example.com', [
    'sink' => '/tmp/' . sha1(file_get_contents('https://example.com'))
]);

upload.php

<?php

$client = new GuzzleHttp\Client();

$client->request('POST', 'https://example.com', [
    'multipart' => [
        [
            'name' => 'foo',
            'contents' => fopen('/path/to/file', 'r'),
        ],
    ],
]);