// Travel to a random page linked in the article or listed on a special page.
// See talk page for documentation. Greg Ubben
//randomlink_start = [ "Wikipedia:Featured articles", "Wikipedia:Featured pictures" ];
//randomlink_hops = 2;
//randomlink_exclude = /^List of/;
//randomlink_paged = true; // cats > 200 entries or multi-paged lists
//randomlink_open = true; // if you want to open in new windows
//randomlink_debug = true; // set this, to debug
randomlink_maxfrom = 22000000; // 10-20% less than max page id
randomlink_maxoffset = 950; // en.wikipedia is limited to 1000
function scrapeLinks( descend )
{
var topnode = document.getElementById('bodyContent') || document;
var node = document.getElementById('mw-subcategories');
var atags = [];
var links = [];
var nspat = /^(Talk|User|Wik\w+|File|MediaWiki|Template|Help|Category|Portal|Book)( talk)?:/i;
var spec = getElementsByClassName(topnode, 'div', 'mw-spcontent');
if (spec.length == 1) topnode = spec[0]; // skip help links at top of specials
if (node && descend)
topnode = node; // pick a sub-category
else
for (var id in {'mw-pages':0, 'mw-category-media':0 }) {
node = document.getElementById( id );
if (node) {
var nodelist = node.getElementsByTagName('a');
for (var i=0; i < nodelist.length; i++)
atags.push( nodelist[i] );
}
}
if (atags.length == 0)
atags = topnode.getElementsByTagName('a');
nextlink:
for (var i=0; i < atags.length; i++) {
var link = atags[i];
var href = link.href;
var title = link.title;
if (!href) // needed?
continue;
if (link.className.search(/\b(external|internal|extiw|image)\b/) >= 0)
continue;
if (href.search(/\/Special:|\?(?!.*redirect=|.*from=.*to=)/) >= 0)
continue;
if (wgIsArticle && wgNamespaceNumber != 14 && title.search(/^(Category|File):|^$|^#/) >= 0)
continue;
if (wgIsArticle && wgNamespaceNumber == 0 && title.search(nspat) >= 0)
continue;
if ((wgAction == "history") != hasClass(link, "mw-userlink"))
continue;
if (link.hostname != location.hostname) // commons.wikimedia.org on images
continue;
if (link.parentNode.id == "coordinates")
continue; // coords too common, or help link
if (typeof randomlink_exclude != "undefined" && title.search(randomlink_exclude) >= 0)
continue;
// Exclude message boxes and the Metadata section on Image pages.
// And also mw-usertool links and comments in page listings.
// And also top links on Recent changes and watchlists.
//
for (var n = link.parentNode; n != topnode; n = n.parentNode) {
if (n.id.search(/^mw-watchlist-options|^recentchangestext/) >= 0)
continue nextlink;
if (n.className.search(/\b(usertool|summary|metadata|.mbox|comment|warn)/) >= 0)
continue nextlink;
}
links.push( link );
}
while (links.length && links[0].parentNode.id.search( /contentSub|jump-to|target/i ) >= 0)
links.shift(); // breadcrumb links
if (links.length && links[0].title == "Wikipedia:FAQ/Categories")
links.shift(); // "learn more" link in cats
return links;
}
function randomLink( links, hops )
{
var continuing = (typeof links == "object" && links == null);
if (typeof links == "undefined" && typeof randomlink_start != "undefined")
links = randomlink_start;
if (typeof hops == "undefined" && typeof randomlink_hops != "undefined")
hops = randomlink_hops;
if (typeof hops == "undefined")
hops = 1;
if (hops > 4) // sanity check; 4 needed for Special:AllPages
hops = 4;
if (typeof links == "string" &&
links.search(/^Special:(WhatLinksHere|RecentChangesLinked)$/i) >= 0)
{
links += "/" + wgPageName + "?limit=250";
if (wgNamespaceNumber == 0)
links += "&namespace=0"; // stay in article space if in it now
}
// Random contrib: Toggles between user, page, user, page, ...
//
if (typeof links == "string" && links == "Special:Contributions")
if (wgPageName.search(/^User:[^\/]+$/) >= 0)
links += "/" + wgPageName.slice(5) + "?namespace=0";
else
links = wgPageName + "?action=history";
if (typeof links == "string")
links = links.split("|");
if (typeof links == "object" && links != null) {
for (var i=0; i < links.length; i++)
links[i] = wgArticlePath.replace("$1", links[i]).replace(/ /g, "_");
hops++;
}
else {
links = scrapeLinks( hops > 1 );
}
if (typeof randomlink_debug != "undefined" && randomlink_debug) {
var msg = links.slice(0);
if (msg.length > 36)
msg.splice( 20, msg.length-35, "..." );
alert( links.length + " links:\n " + msg.join("\n "));
}
if (links.length == 0)
return alert("I am unable to comply.");
var newpage = links[ Math.floor(links.length * Math.random()) ].toString();
if (typeof randomlink_paged != "undefined" && randomlink_paged)
newpage = pagedUrl( newpage );
if (wgCanonicalNamespace == "Category" && newpage.indexOf("/Category:") == -1)
hops = 1;
if (--hops > 0) {
newpage += (newpage.indexOf("?") >= 0) ? "&" : "?";
newpage += "random_hops=" + hops;
}
// WikiProjects organize by talk pages, but let's end on the subject page.
//
if ((wgCanonicalNamespace == "Category" || wgCanonicalSpecialPageName == "Whatlinkshere")
&& continuing && hops <= 0)
newpage = newpage.replace("/Talk:", "/").replace("_talk:", ":");
if (typeof randomlink_open != "undefined" && randomlink_open && !continuing)
window.open( newpage );
else
window.location = newpage;
}
function pagedUrl( url )
{
var param = "";
var value;
var alphabet = "!abcdefghijklmnoprstuvwy~";
if (url.indexOf("/Category:") >= 0) {
value = alphabet.charAt(alphabet.length * Math.random()).toUpperCase()
+ alphabet.charAt(alphabet.length * Math.random());
param = (value < "M" ? "from" : "until");
}
if (url.indexOf("Special:WhatLinksHere") >= 0) {
param = "from";
value = Math.floor( randomlink_maxfrom * Math.random() );
// Clustering will hurt randomness, but better than nothing
}
if (url.search(/Special:\w+s\b/) >= 0) {
param = "offset";
value = Math.floor( randomlink_maxoffset * Math.random() );
}
if (param) {
url += (url.indexOf("?") >= 0) ? "&" : "?";
url += param + "=" + encodeURIComponent(value);
}
return url;
}
$( function()
{
var hops = document.URL.match( /[?&]random_hops=(\d+)/ );
if (hops) randomLink( null, hops[1] );
var where = 'this page';
if (typeof randomlink_start != 'undefined')
where = randomlink_start.toString().slice(0,500);
addPortletLink('p-navigation', 'javascript:randomLink()', 'Random link',
'n-randomlink', 'Follow a randomly chosen link on ' + where, '@');
});
