/* vim: ts=4 noet ai :
$Id: $
Linkchecker - (c) 2006 J.Q. la Poutre
This script spiders all links on a web page and tries if they
can be followed.
Somewhat more detailed:
Every HTTP link is polled with a HEAD request, and, depending on the
returned status code, the link is visually marked (by color and title)
according to the result.
Some remarks
- pages in frames are omitted
- only HTTP(S) links are checked
- linked images are replaced by their ALT text (or "img")
- the script uses a spider pool of max. 4 simultaneous requests
- time out per request is handled by the browser, wchich can take some time
- check for the NoScript extension settings if "Initializing..." takes forever.
- relative links don't work in locally loaded files (GM security limitation)
LICENSE
=======
This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the
Free Software Foundation; either version 2 of the License, or (at your
option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
CHANGELOG
=========
TODO:
- smart handling of frame sites
- use <base href...>
- parse <area href...> elements
- parse "invisible" link elements: <link rel=...> etc.
Version 1.00
- initial release
*/
// ==UserScript==
// @name Linkchecker
// @namespace http://joe.lapoutre.com/BoT/Javascript
// @description Check all links on a web page
// @include *testpage*
// @version 1.00
// ==/UserScript==
// global object
var gLinkchecker = {
MAXREQ: 4, // max. number of simultaneous page requests
links: [], // link objects
requests: 0, // number of active XHR's
errors: 0, // number of erroneous links
interval: null, // heartbeat interval
populate: function() {
this.replaceImgs();
var ll = document.evaluate("//a[@href]", document, null,
XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = 0; i < ll.snapshotLength; i++) {
var l = ll.snapshotItem(i);
href = l.getAttribute("href");
l.style.background = "white none";
l.style.color = "darkblue";
l.textDecoration = "underline";
l.setAttribute("title", "Link wil be checked");
// filter out javascript: mailto: ftp:// etc. links
if (href.match(/^(?!http)[^\/:]{2,}:/i)) {
l.setAttribute("title", "Link type not checked");
l.style.backgroundColor = "silver";
continue;
}
// skip links to internal anchors
if (href.indexOf('#') == 0) {
l.setAttribute("title", "Internal anchor, not ckecked");
l.style.backgroundColor = "silver";
continue;
}
this.links.push(new Link(l, href));
}
},
replaceImgs: function() {
var ll = document.evaluate("//a[@href]/img", document, null,
XPathResult.UNORDERED_NODE_SNAPSHOT_TYPE, null);
for (var i = 0; i < ll.snapshotLength; i++) {
var l = ll.snapshotItem(i);
var txt = "[" + (l.getAttribute("alt") || "img") + "]";
var tn = document.createTextNode(txt);
l.parentNode.replaceChild(tn, l);
}
},
evtStart: function() {
var btn = document.getElementById("gm_lichckr_btn");
btn.setAttribute("value", "Initializing...");
btn.style.backgroundColor = "orange";
btn.removeEventListener('click', gLinkchecker.evtStart, true);
btn.addEventListener('click', gLinkchecker.evtStop, true);
gLinkchecker.populate();
gLinkchecker.interval = setInterval(heartBeat, 333);
},
evtStop: function() {
if (window.confirm("Stop Link Checker?")) {
clearInterval(gLinkchecker.interval);
// output results right away
var btn = document.getElementById("gm_lichckr_btn");
btn.setAttribute("value", "Resume");
btn.style.backgroundColor = "lime";
btn.removeEventListener('click', gLinkchecker.evtStop, true);
btn.addEventListener('click', gLinkchecker.evtResume, true);
}
},
evtResume: function() {
gLinkchecker.interval = setInterval(heartBeat, 200);
var btn = document.getElementById("gm_lichckr_btn");
btn.setAttribute("value", "Resuming...");
btn.style.backgroundColor = "orange";
btn.removeEventListener('click', gLinkchecker.evtResume, true);
btn.addEventListener('click', gLinkchecker.evtStop, true);
},
evtDone: function() {
var btn = document.getElementById("gm_lichckr_btn");
btn.setAttribute("value", "Found " + gLinkchecker.errors +
" bad link" + ((gLinkchecker.errors != 1) ? "s" : ""));
btn.setAttribute("disabled", "disabled");
btn.style.backgroundColor = "lime";
},
initialize: function() {
// work in main window only (too many iframe crap sites, sorry)
if (window != top) return;
// "start" button on page
var ovl = document.createElement("input");
ovl.setAttribute("id", "gm_lichckr_btn");
ovl.setAttribute("type", "button");
ovl.setAttribute("value", "Check links");
ovl.style.position = "fixed";
ovl.style.zIndex = 99999; // insane, sometimes needed though
ovl.style.top = "12px";
ovl.style.right = "12px";
ovl.style.backgroundColor = "lime";
// start watching request queue every interval period
ovl.addEventListener('click', gLinkchecker.evtStart, true);
document.getElementsByTagName("body")[0].appendChild(ovl);
}
};
/*
* returns a closure with embedded object reference
* see: http://jibbering.com/faq/faq_notes/closures.html#clObjI
*/
function getProcessFunc(obj) {
return (function(res) {
// for more HTTP 1.1 status codes, see
// http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html
switch (res.status) {
// OK results
case 200:
case 302: // redirect of kinds
case 303:
case 304: // not modified
// the 3XX family is handled by XHR,
// not likely that we see these codes
obj.elt.style.backgroundColor = "#7CFC00";
break;
// authorization required
case 401: // only when no valid credentials were used
obj.elt.style.backgroundColor = "yellow";
break;
// likely persistent errors
case 403: // forbidden
case 404: // not found
case 500: // internal server error
case 501: // not implemented
case 502: // bad gateway
obj.elt.style.backgroundColor = "#FF6347";
gLinkchecker.errors++;
break;
// possibly transient errors
case 405: // method not allowed
case 503: // service unavailable
obj.elt.style.backgroundColor = "orange";
gLinkchecker.errors++;
break;
case "XHR": // XHR throwed something
obj.elt.style.backgroundColor = "silver";
break;
default:
}
obj.elt.setAttribute("title",
(res.status || 'Status:') + " " +
(res.statusText || 'Unknonwn'));
// flag this request as complete, decrease counter
gLinkchecker.requests--;
// now do away with the link object, to give garbage collection a chance
obj = null;
});
}
// link object
function Link(elt, href) {
this.elt = elt;
this.href = mkAbsolute(href);
// do a HEAD request
this.ping = function() {
try {
var func = getProcessFunc(this);
// XHR, greasemonkey version works cross site.
GM_xmlhttpRequest(
{
method: 'HEAD',
url: this.href,
headers: {
'User-Agent': 'Mozilla/5.0 (compatible)',
'Referer': window.location.href
},
onload: func,
// weird behavior of XHR wit HEAD in Firefox,
// apparently the error handler is called,
// when the request works perfectly fine
onerror: func
});
gLinkchecker.requests++;
} catch (e) {
func({status: "XHR", statusText: e.toString()});
}
};
}
// make link absolute,
// offset by current window.location.href
// FIXME: or the <base> element
function mkAbsolute(rel) {
// weird slashdot, omits protocol part,
// like "//ask.slashdot.org/path"
if (rel.indexOf("//") == 0) {
rel = window.location.protocol + rel;
}
// not relative at all:
if (rel.match(/^https?:/i)) return rel;
var base = window.location.protocol + "//" + window.location.host;
// absolute from document root (starts with slash):
if (rel.indexOf("/") == 0) {
return base + rel;
}
var b = window.location.pathname.split("/");
// strip the page component, or last slash of path name:
b.pop();
var r = rel.split("/");
// strip off one level for any "../" sequence
while (r[0] == "..") {
r.shift();
b.pop();
}
return base + b.join("/") + "/" + r.join("/");
}
function heartBeat() {
if ((gLinkchecker.requests < gLinkchecker.MAXREQ) &&
gLinkchecker.links.length) {
// update remaining links
var btn = document.getElementById("gm_lichckr_btn");
btn.setAttribute("value", "Spidering (" + gLinkchecker.links.length + ")...");
// work: shift next URL from stack
gLinkchecker.links.shift().ping();
}
if ((gLinkchecker.requests <= 0) && (gLinkchecker.links.length == 0)) {
clearInterval(gLinkchecker.interval);
// output results after last request has been processed
//outputToTab(gLinkchecker.toDotString());
gLinkchecker.evtDone();
}
}
gLinkchecker.initialize();
// end user script
