csrf-magic.js

   1 /**
   2  * @file
   3  *
   4  * Rewrites XMLHttpRequest to automatically send CSRF token with it. In theory
   5  * plays nice with other JavaScript libraries, needs testing though.
   6  */
   7
   8 // Here are the basic overloaded method definitions
   9 // The wrapper must be set BEFORE onreadystatechange is written to, since
  10 // a bug in ActiveXObject prevents us from properly testing for it.
  11 CsrfMagic = function(real) {
  12     // try to make it ourselves, if you didn't pass it
  13     if (!real) try { real = new XMLHttpRequest; } catch (e) {;}
  14     if (!real) try { real = new ActiveXObject('Msxml2.XMLHTTP'); } catch (e) {;}
  15     if (!real) try { real = new ActiveXObject('Microsoft.XMLHTTP'); } catch (e) {;}
  16     if (!real) try { real = new ActiveXObject('Msxml2.XMLHTTP.4.0'); } catch (e) {;}
  17     this.csrf = real;
  18     // properties
  19     var csrfMagic = this;
  20     real.onreadystatechange = function() {
  21         csrfMagic._updateProps();
  22         return csrfMagic.onreadystatechange ? csrfMagic.onreadystatechange() : null;
  23     };
  24     csrfMagic._updateProps();
  25 }
  26
  27 CsrfMagic.prototype = {
  28
  29     open: function(method, url, async, username, password) {
  30         if (method == 'POST') this.csrf_isPost = true;
  31         // deal with Opera bug, thanks jQuery
  32         if (username) return this.csrf_open(method, url, async, username, password);
  33         else return this.csrf_open(method, url, async);
  34     },
  35     csrf_open: function(method, url, async, username, password) {
  36         if (username) return this.csrf.open(method, url, async, username, password);
  37         else return this.csrf.open(method, url, async);
  38     },
  39
  40     send: function(data) {
  41         if (!this.csrf_isPost) return this.csrf_send(data);
  42         prepend = csrfMagicName + '=' + csrfMagicToken + '&';
  43         if (this.csrf_purportedLength === undefined) {
  44             this.csrf_setRequestHeader("Content-length", this.csrf_purportedLength + prepend.length);
  45             delete this.csrf_purportedLength;
  46         }
  47         delete this.csrf_isPost;
  48         return this.csrf_send(prepend + data);
  49     },
  50     csrf_send: function(data) {
  51         return this.csrf.send(data);
  52     },
  53
  54     setRequestHeader: function(header, value) {
  55         // We have to auto-set this at the end, since we don't know how long the
  56         // nonce is when added to the data.
  57         if (this.csrf_isPost && header == "Content-length") {
  58             this.csrf_purportedLength = value;
  59             return;
  60         }
  61         return this.csrf_setRequestHeader(header, value);
  62     },
  63     csrf_setRequestHeader: function(header, value) {
  64         return this.csrf.setRequestHeader(header, value);
  65     },
  66
  67     abort: function() {
  68         return this.csrf.abort();
  69     },
  70     getAllResponseHeaders: function() {
  71         return this.csrf.getAllResponseHeaders();
  72     },
  73     getResponseHeader: function(header) {
  74         return this.csrf.getResponseHeader(header);
  75     } // ,
  76 }
  77
  78 // proprietary
  79 CsrfMagic.prototype._updateProps = function() {
  80     this.readyState = this.csrf.readyState;
  81     if (this.readyState == 4) {
  82         this.responseText = this.csrf.responseText;
  83         this.responseXML  = this.csrf.responseXML;
  84         this.status       = this.csrf.status;
  85         this.statusText   = this.csrf.statusText;
  86     }
  87 }
  88 CsrfMagic.process = function(base) {
  89     var prepend = csrfMagicName + '=' + csrfMagicToken;
  90     if (base) return prepend + '&' + base;
  91     return prepend;
  92 }
  93 // callback function for when everything on the page has loaded
  94 CsrfMagic.end = function() {
  95     // This rewrites forms AGAIN, so in case buffering didn't work this
  96     // certainly will.
  97     forms = document.getElementsByTagName('form');
  98     for (var i = 0; i < forms.length; i++) {
  99         form = forms[i];
 100         if (form.method.toUpperCase() !== 'POST') continue;
 101         if (form.elements[csrfMagicName]) continue;
 102         var input = document.createElement('input');
 103         input.setAttribute('name',  csrfMagicName);
 104         input.setAttribute('value', csrfMagicToken);
 105         input.setAttribute('type',  'hidden');
 106         form.appendChild(input);
 107     }
 108 }
 109
 110 // Sets things up for Mozilla/Opera/nice browsers
 111 // We very specifically match against Internet Explorer, since they haven't
 112 // implemented prototypes correctly yet.
 113 if (window.XMLHttpRequest && window.XMLHttpRequest.prototype && '\v' != 'v') {
 114     var x = XMLHttpRequest.prototype;
 115     var c = CsrfMagic.prototype;
 116
 117     // Save the original functions
 118     x.csrf_open = x.open;
 119     x.csrf_send = x.send;
 120     x.csrf_setRequestHeader = x.setRequestHeader;
 121
 122     // Notice that CsrfMagic is itself an instantiatable object, but only
 123     // open, send and setRequestHeader are necessary as decorators.
 124     x.open = c.open;
 125     x.send = c.send;
 126     x.setRequestHeader = c.setRequestHeader;
 127 } else {
 128     // The only way we can do this is by modifying a library you have been
 129     // using. We support YUI, script.aculo.us, prototype, MooTools,
 130     // jQuery, Ext and Dojo.
 131     if (window.jQuery) {
 132         // jQuery didn't implement a new XMLHttpRequest function, so we have
 133         // to do this the hard way.
 134         jQuery.csrf_ajax = jQuery.ajax;
 135         jQuery.ajax = function( s ) {
 136             if (s.type && s.type.toUpperCase() == 'POST') {
 137                 s = jQuery.extend(true, s, jQuery.extend(true, {}, jQuery.ajaxSettings, s));
 138                 if ( s.data && s.processData && typeof s.data != "string" ) {
 139                     s.data = jQuery.param(s.data);
 140                 }
 141                 s.data = CsrfMagic.process(s.data);
 142             }
 143             return jQuery.csrf_ajax( s );
 144         }
 145     }
 146     if (window.Prototype) {
 147         // This works for script.aculo.us too
 148         Ajax.csrf_getTransport = Ajax.getTransport;
 149         Ajax.getTransport = function() {
 150             return new CsrfMagic(Ajax.csrf_getTransport());
 151         }
 152     }
 153     if (window.MooTools) {
 154         Browser.csrf_Request = Browser.Request;
 155         Browser.Request = function () {
 156             return new CsrfMagic(Browser.csrf_Request());
 157         }
 158     }
 159     if (window.YAHOO) {
 160         // old YUI API
 161         YAHOO.util.Connect.csrf_createXhrObject = YAHOO.util.Connect.createXhrObject;
 162         YAHOO.util.Connect.createXhrObject = function (transaction) {
 163             obj = YAHOO.util.Connect.csrf_createXhrObject(transaction);
 164             obj.conn = new CsrfMagic(obj.conn);
 165             return obj;
 166         }
 167     }
 168     if (window.Ext) {
 169         // Ext can use other js libraries as loaders, so it has to come last
 170         // Ext's implementation is pretty identical to Yahoo's, but we duplicate
 171         // it for comprehensiveness's sake.
 172         Ext.lib.Ajax.csrf_createXhrObject = Ext.lib.Ajax.createXhrObject;
 173         Ext.lib.Ajax.createXhrObject = function (transaction) {
 174             obj = Ext.lib.Ajax.csrf_createXhrObject(transaction);
 175             obj.conn = new CsrfMagic(obj.conn);
 176             return obj;
 177         }
 178     }
 179     if (window.dojo) {
 180         // NOTE: this doesn't work with latest dojo
 181         dojo.csrf__xhrObj = dojo._xhrObj;
 182         dojo._xhrObj = function () {
 183             return new CsrfMagic(dojo.csrf__xhrObj());
 184         }
 185     }
 186 }