85 lines
1.6 KiB
JavaScript
85 lines
1.6 KiB
JavaScript
/**
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* Module dependencies
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*/
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var debug = require('debug')('jsonp');
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/**
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* Module exports.
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*/
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module.exports = jsonp;
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/**
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* Callback index.
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*/
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var count = 0;
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/**
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* Noop function.
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*/
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function noop(){}
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/**
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* JSONP handler
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*
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* Options:
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* - param {String} qs parameter (`callback`)
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* - timeout {Number} how long after a timeout error is emitted (`60000`)
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*
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* @param {String} url
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* @param {Object|Function} optional options / callback
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* @param {Function} optional callback
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*/
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function jsonp(url, opts, fn){
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if ('function' == typeof opts) {
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fn = opts;
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opts = {};
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}
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if (!opts) opts = {};
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var prefix = opts.prefix || '__jp';
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var param = opts.param || 'callback';
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var timeout = null != opts.timeout ? opts.timeout : 60000;
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var enc = encodeURIComponent;
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var target = document.getElementsByTagName('script')[0] || document.head;
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var script;
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var timer;
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// generate a unique id for this request
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var id = prefix + (count++);
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if (timeout) {
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timer = setTimeout(function(){
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cleanup();
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if (fn) fn(new Error('Timeout'));
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}, timeout);
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}
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function cleanup(){
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script.parentNode.removeChild(script);
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window[id] = noop;
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}
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window[id] = function(data){
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debug('jsonp got', data);
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if (timer) clearTimeout(timer);
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cleanup();
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if (fn) fn(null, data);
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};
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// add qs component
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url += (~url.indexOf('?') ? '&' : '?') + param + '=' + enc(id);
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url = url.replace('?&', '?');
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debug('jsonp req "%s"', url);
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// create script
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script = document.createElement('script');
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script.src = url;
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target.parentNode.insertBefore(script, target);
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}
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