[tampermonkey] vk image save

convert.php

<?php

/**
 * Decode base64 encoded string with '+/=' replaced with '._-'.
 * @param type $s
 * @return type
 */
function base64Xd($s) {
	return base64_decode(strtr($s, '._-', '+/='));
}

/**
 * Convert $http_response_header into k=>v map.
 * @param Array $list
 * @return Array
 */
function mapHeaders($list) {
	return array_reduce(array_slice($list, 1), function($carry, $item) {
		list($k, $v) = explode(':', $item, 2);
		$carry[strtolower($k)] = ltrim($v);
		return $carry;
	}, []);
}

function main() {
	ini_set('display_errors', 0);

	if (isset($_GET['url'])) {
		$url = base64Xd($_GET['url']);

		if ($url !== false) {
			$urlParts = parse_url($url);

			if ($urlParts !== false && ($urlParts['scheme'] === 'http' || $urlParts['scheme'] === 'https')) {
				$filename = basename($urlParts['path']);

				if (strlen($filename)) {
					$response = file_get_contents($url, false, stream_context_create([
						'http' => [
							'user_agent' => $_SERVER['HTTP_USER_AGENT'],
							'timeout' => 10,
						],
					]));

					if ($response !== false) {
						$headers = mapHeaders($http_response_header);

						if (isset($headers['content-type'])) {
							header('Content-Type: ' . $headers['content-type']);
							header("Content-Disposition: attachment; filename*=UTF-8''" . urlencode($filename));
							echo $response;
						}
					}
				}
			}
		}
	}
}

main();

vk-image-save.user.js

// ==UserScript==
// @name         vk image save
// @namespace    http://tampermonkey.net/
// @version      0.8.1
// @downloadURL  https://gist.githubusercontent.com/dandelionred/8c6059be4b2fdc55bb990baea8298a67/raw/vk-image-save.user.js
// @updateURL    https://gist.githubusercontent.com/dandelionred/8c6059be4b2fdc55bb990baea8298a67/raw/vk-image-save.user.js
// @match        https://m.vk.com/*
// ==/UserScript==

(function () {
	'use strict';

	let location = null;

	const html = `
<style>
#down-button {
    position: absolute;
    bottom: 0;
    right: 0;
    z-index: 2;
    text-align: right;
}
#down-button a {
    display: inline-block;
    line-height: 48px;
    padding: 0 24px;
    color: lightgray;
    font-weight: bold;
    font-family: monospace;
}
</style>
<div id="down-button"></div>
`;

	function log(s) {
		console.log("[" + (new Date()).getTime() + "] " + s);
	}

	/**
	 * Convert unicode string to utf-8, base64 encode, replace "+/=" with "._-".
	 * @param {String} s
	 * @returns {String}
	 */
	function base64X(s) {
		const pairs = {
			"+": ".",
			"/": "_",
			"=": "-"
		};

		return window.btoa(unescape(encodeURIComponent(s))).replace(/[+/=]/g, m => pairs[m]);
	}

	function main() {
		const z_photoview = document.getElementById("z_photoview");
		if (!z_photoview) {
			location = null;
			return;
		}

		const img = z_photoview.querySelector("#zpv_center img.zpv_img");
		if (!img || img.src === location || img.src.slice(-10) === "/blank.gif") {
			return;
		}

		let downButton = document.getElementById("down-button");

		if (!downButton) {
			z_photoview.querySelector(".zpv_bottom_body").insertAdjacentHTML("beforeend", html);
			downButton = document.getElementById("down-button");
		}

		location = img.src;

		if (!downButton.firstChild) {
			let a = document.createElement("a");
			a.innerText = "save";
			downButton.appendChild(a);
		}

		downButton.firstChild.href = "http://local.download1.net:81/convert.php?url=" + base64X(img.src);
	}

	setInterval(main, 500);
})();