Add CDN-latest.js for loading the latest copy from a cdn without knowing the version.

2017-04-10 16:15:02 -04:00 · 2017-04-10 16:15:02 -04:00 · f865b6a83a
commit f865b6a83a
parent 4ddd35cd1c
1 changed files with 129 additions and 0 deletions
--- a/unpacked/CDN-latest.js
+++ b/unpacked/CDN-latest.js
@ -0,0 +1,129 @@
+(function () {
+
+   var CDN = {
+     'cdnjs.cloudflare.com': {
+       api: 'https://api.cdnjs.com/libraries/mathjax?fields=version',
+       version: 'version',
+       mathjax: 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/'
+     },
+     
+     'cdn.rawgit.com': {
+       api: 'https://api.github.com/repos/mathjax/mathjax/releases/latest',
+       version: 'tag_name',
+       mathjax: 'https://cdn.rawgit.com/mathjax/MathJax/'
+     },
+     
+     'cdn.jsdelivr.net': {
+       api: 'https://api.jsdelivr.com/v1/jsdelivr/libraries?name=mathjax&lastversion=*',
+       version: 'lastversion',
+       mathjax: 'https://cdn.jsdelivr.net/mathjax/'
+     }
+   };
+   
+   function Error(message) {
+     if (console && console.log) console.log(message);
+   }
+   
+   function getScript() {
+     if (document.currentScript) return document.currentScript;
+     var scripts = document.getElementsByTagName("script");
+     for (var i = 0, m = scripts.length; i < m; i++) {
+       var script = scripts[i];
+       for (var cdn in CDN) {if (CDN.hasOwnProperty(cdn)) {
+         var url = CDN[cdn].mathjax;
+         if (script.src && script.src.substr(0,url.length) === url) return script;
+       }}
+     }
+   }
+   
+   function getCDN(script) {
+     if (!script) return;
+     var cdn = script.src.replace(/https:\/\//,'').replace(/[\/\?].*/,'');
+     return CDN[cdn];
+   }
+   
+   var cookiePattern = /(?:^|;\s*)mjx\.latest=([^;]*)(?:;|$)/;
+   function getVersion() {
+     var match;
+     try {match = cookiePattern.exec(document.cookie)} catch (err) {}
+     if (match && match[1] !== '') return match[1];
+   }
+   function setVersion(version) {
+     cookie = 'mjx.latest=' + version;
+     var time = new Date();
+     time.setDate(time.getDate() + 7);
+     cookie += '; expires=' + time.toGMTString();
+     cookie += '; path=/';
+     try {document.cookie = cookie} catch (err) {}
+   }
+   
+   function getXMLHttpRequest() {
+     if (window.XMLHttpRequest) return new XMLHttpRequest();
+     if (window.ActiveXObject) {
+       try {return new ActiveXObject("Msxml2.XMLHTTP")} catch (err) {}
+       try {return new ActiveXObject("Microsoft.XMLHTTP")} catch (err) {}
+     }
+   }
+   
+   function loadMathJax(url) {
+     var script = document.createElement('script');
+     script.type = 'text/javascript';
+     script.async = true;
+     script.src = url;
+     var head = document.head || document.getElementsByTagName('head')[0] || document.body;
+     if (head) {
+       head.appendChild(script);
+     } else {
+       Error("Can't find the document <head> element");
+     }
+   }
+   
+   function loadDefaultMathJax() {
+     var script = getScript();
+     if (script) {
+       loadMathJax(script.src.replace(/CDN-latest\.js/,"MathJax.js"));
+     } else {
+       Error("Can't determine the URL for loading MathJax");
+     }
+   }
+   
+   function getLatestMathJax(cdn,config,unpacked) {
+     var request = getXMLHttpRequest();
+     if (request) {
+       request.onreadystatechange = function() {
+         if (request.readyState === 4) {
+           if (request.status === 200) {
+             var json = JSON.parse(request.responseText);
+             if (json instanceof Array) json = json[0];
+             setVersion(json[cdn.version]);
+             loadMathJax(cdn.mathjax + json[cdn.version] + unpacked + '/MathJax.js' + config);
+           } else {
+             Error("Problem aquiring MathJax version: status = " + request.status);
+             laodDefaultMathJax();
+           }
+         }
+       }
+       request.open('GET', cdn.api, true); 
+       request.send(null);
+     } else {
+       Error("Can't create XMLHttpRequest object");
+       loadDefaultMathJax();
+     }
+   }
+   
+   var script = getScript();
+   var cdn = getCDN(script);
+   if (cdn) {
+     var config = script.src.replace(/.*?(\?|$)/,"$1");
+     var unpacked = (script.src.match(/\/unpacked\/CDN-latest\.js/) ? "/unpacked" : "");
+     var version = getVersion();
+     if (version) {
+       loadMathJax(cdn.mathjax + version + unpacked + '/MathJax.js' + config);
+     } else {
+       getLatestMathJax(cdn, config, unpacked);
+     }
+   } else {
+     loadDefaultMathJax();
+   }
+
+})();