4chan Image Downloader

4chan-images.php

#!/usr/bin/env php
<?php error_reporting(E_ALL); set_time_limit(0);

// ref: https://github.com/4chan/4chan-API

if (php_sapi_name() !== "cli" || $argc !== 2) {
	echo "Usage: php ", $argv[0], " [board]";
	exit(1);
}

$aurl = "http://a.4cdn.org";
$exts = array(".jpg", ".jpeg", ".png", ".gif", ".bmp");
$api = file_get_contents("{$aurl}/{$argv[1]}/catalog.json");
$json = json_decode($api);

if (!is_dir($bin = "images")) {
	mkdir($bin, 0755);
}

foreach ($json as $page) {
	foreach ($page->threads as $thread) {
		$api2 = file_get_contents("{$aurl}/{$argv[1]}/thread/{$thread->no}.json");
		$json2 = json_decode($api2);

		foreach ($json2->posts as $post) {
			if (isset($post->tim) && isset($post->ext)) {
				if (in_array($post->ext, $exts)) {
					$fn = $post->tim.$post->ext;
					download("http://i.4cdn.org/{$argv[1]}/{$fn}", "{$bin}/{$fn}");
				}
			}
		}
	}
}

function download ($url, $fn) {
	if (!file_exists($fn)) {
		echo "Downloading: ", $url, PHP_EOL;
		file_put_contents($fn, file_get_contents($url));
	}
}