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      1 <!--
      2 Copyright (C) 2011 Google Inc. All rights reserved.
      3 
      4 Redistribution and use in source and binary forms, with or without
      5 modification, are permitted provided that the following conditions
      6 are met:
      7 1. Redistributions of source code must retain the above copyright
      8    notice, this list of conditions and the following disclaimer.
      9 2. Redistributions in binary form must reproduce the above copyright
     10    notice, this list of conditions and the following disclaimer in the
     11    documentation and/or other materials provided with the distribution.
     12 
     13 THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
     14 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     15 THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
     17 BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     18 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     19 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     20 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     21 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     22 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
     23 THE POSSIBILITY OF SUCH DAMAGE.
     24 -->
     25 
     26 <script>
     27 
     28 var net = net || {};
     29 
     30 (function () {
     31 
     32 net.json = function(url)
     33 {
     34     return net.ajax({
     35         url: url,
     36         parse: function(xhr) {
     37             return JSON.parse(xhr.responseText);
     38         }
     39     });
     40 };
     41 
     42 net.xml = function(url)
     43 {
     44     return net.ajax({
     45         url: url,
     46         parse: function(xhr) {
     47             return xhr.responseXML;
     48         }
     49     });
     50 };
     51 
     52 net.ajax = function(options)
     53 {
     54     return new Promise(function(resolve, reject) {
     55         var xhr = new XMLHttpRequest();
     56         var method = options.type || 'GET';
     57         var async = true;
     58         xhr.open(method, options.url, async);
     59         xhr.onload = function() {
     60             if (xhr.status == 200) {
     61                 if (options.parse)
     62                     resolve(options.parse(xhr));
     63                 else
     64                     resolve(xhr.responseText);
     65             }
     66             else if (xhr.status != 200)
     67                 reject(Error(xhr.statusText));
     68         };
     69         xhr.onerror = function(error) {
     70             reject(error);
     71         };
     72         var data = options.data || null;
     73         if (data)
     74             xhr.setRequestHeader("content-type","application/x-www-form-urlencoded");
     75         xhr.send(data);
     76     });
     77 };
     78 
     79 net.probe = function(url)
     80 {
     81     return net.ajax({
     82         url: url,
     83         type: 'HEAD',
     84     });
     85 };
     86 
     87 net._parseJSONP = function(jsonp)
     88 {
     89     if (!jsonp)
     90         return {};
     91 
     92     if (!jsonp.match(/^[^{[]*\(/))
     93         return JSON.parse(jsonp);
     94 
     95     var startIndex = jsonp.indexOf('(') + 1;
     96     var endIndex = jsonp.lastIndexOf(')');
     97     if (startIndex == 0 || endIndex == -1)
     98         return {};
     99     return JSON.parse(jsonp.substr(startIndex, endIndex - startIndex));
    100 };
    101 
    102 // We use XMLHttpRequest and CORS to fetch JSONP rather than using script tags.
    103 // That's better for security and performance, but we need the server to cooperate
    104 // by setting CORS headers.
    105 net.jsonp = function(url)
    106 {
    107     return net.ajax({
    108         url: url,
    109     }).then(function(jsonp) {
    110         return net._parseJSONP(jsonp);
    111     }).catch(function(error) {
    112         return {};
    113     });
    114 };
    115 
    116 })();
    117 
    118 </script>