Wayback Machine Image Fixer

Attempts to fix broken images by replacing them with working timestamps based on JSON results
当前为 2015-10-04 提交的版本，查看最新版本。
换行
// ==UserScript==
// @name          Wayback Machine Image Fixer
// @namespace     DoomTay
// @description   Attempts to fix broken images by replacing them with working timestamps based on JSON results
// @include       http://web.archive.org/web/*
// @exclude       http://web.archive.org/web/*.jpg
// @exclude       http://web.archive.org/web/*.jpeg
// @exclude       http://web.archive.org/web/*.png
// @exclude       http://web.archive.org/web/*.gif
// @exclude       http://web.archive.org/web/*.bmp
// @version       1.0.0.20151004173702
// @grant         GM_xmlhttpRequest 

// ==/UserScript==

var pics = document.images;

function replaceImage(target)
{
	var originalURL = target.src.substring(target.src.lastIndexOf('http'));
	var newURL = GM_xmlhttpRequest({
		url: "http://archive.org/wayback/available?url=" + originalURL,
		method: "GET",
		headers: {"Accept": "application/json"},
		onload: function(response) {
			if(JSON.parse(response.responseText)["archived_snapshots"]["closest"] == undefined)
			{
				//Try and "expose" image links that are unclickable due to the image not loading
				if(target.alt == "" && target.width == 0)
				{
					//Changing the source is pretty hacky, but it's the only way I can think of to turn "invisible" image links into something clickable
					target.src = target.src.substring(target.src.lastIndexOf("http"));
					target.width = 25;
					target.height = 25;
				}
				return;
			}
			target.src = JSON.parse(response.responseText)["archived_snapshots"]["closest"]["url"];
		}
	});
}

function isImageValid(url)
{
	var lookup = GM_xmlhttpRequest({
		url: url,
		method: "HEAD",
		synchronous: true
	});
	//Going off of response code is unreliable. Sometimes an image will return a status code of 200 even though it would redirect to an error page should you view the image directly, so we're looking at content type instead
	return (lookup.responseHeaders.indexOf("Content-Type: text/html") == -1);
}

for(var i = 0; i < pics.length; i++)
{
	//Skip over stuff related to the Wayback Machine toolbar
	if(containsParent(pics[i],document.getElementById("wm-ipp"))) continue;
	//See if the image needs to be replaced in the first place
	if (isImageValid(pics[i].src)) continue;
	replaceImage(pics[i]);
}

function containsParent(node,parent)
{
	var baseNode = node;
	var found = false;
	while(baseNode != document)
	{
		baseNode = baseNode.parentNode;
		if(baseNode == parent)
		{
			return true;
		}
	}
	return false;
}