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| 1 <!-- | |
| 2 Copyright (c) 2014 The Polymer Project Authors. All rights reserved. | |
| 3 This code may only be used under the BSD style license found at http://polymer.g
ithub.io/LICENSE.txt | |
| 4 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt | |
| 5 The complete set of contributors may be found at http://polymer.github.io/CONTRI
BUTORS.txt | |
| 6 Code distributed by Google as part of the polymer project is also | |
| 7 subject to an additional IP rights grant found at http://polymer.github.io/PATEN
TS.txt | |
| 8 --> | |
| 9 <link rel="import" href="../polymer/polymer.html"> | |
| 10 | |
| 11 <!-- | |
| 12 Supports sharing a JSONP-based JavaScript library. | |
| 13 | |
| 14 <core-shared-lib on-core-shared-lib-load="{{load}}" url="https://apis.google
.com/js/plusone.js?onload=%%callback%%"> | |
| 15 | |
| 16 Multiple components can request a library using a `core-shared-lib` component an
d only one copy of that library will | |
| 17 loaded from the network. | |
| 18 | |
| 19 Currently, the library must support JSONP to work as a shared-lib. | |
| 20 | |
| 21 Some libraries require a specific global function be defined. If this is the cas
e, specify the `callbackName` property. | |
| 22 | |
| 23 Where possible, you should use an HTML Import to load library dependencies. Rath
er than using this element, | |
| 24 create an import (`<link rel="import" href="lib.html">`) that wraps loading the
.js file: | |
| 25 | |
| 26 lib.html: | |
| 27 | |
| 28 <script src="lib.js"></script> | |
| 29 | |
| 30 @group Polymer Core Elements | |
| 31 @element core-shared-lib | |
| 32 --> | |
| 33 <polymer-element name="core-shared-lib" attributes="url notifyEvent callbackName
"> | |
| 34 <script> | |
| 35 (function() { | |
| 36 | |
| 37 Polymer({ | |
| 38 | |
| 39 notifyEvent: 'core-shared-lib-load', | |
| 40 | |
| 41 ready: function() { | |
| 42 if (!this.url && this.defaultUrl) { | |
| 43 this.url = this.defaultUrl; | |
| 44 } | |
| 45 }, | |
| 46 | |
| 47 urlChanged: function() { | |
| 48 require(this.url, this, this.callbackName); | |
| 49 }, | |
| 50 | |
| 51 provide: function() { | |
| 52 this.async('notify'); | |
| 53 }, | |
| 54 | |
| 55 notify: function() { | |
| 56 this.fire(this.notifyEvent, arguments); | |
| 57 } | |
| 58 | |
| 59 }); | |
| 60 | |
| 61 var apiMap = {}; | |
| 62 | |
| 63 function require(url, notifiee, callbackName) { | |
| 64 // make hashable string form url | |
| 65 var name = nameFromUrl(url); | |
| 66 // lookup existing loader instance | |
| 67 var loader = apiMap[name]; | |
| 68 // create a loader as needed | |
| 69 if (!loader) { | |
| 70 loader = apiMap[name] = new Loader(name, url, callbackName); | |
| 71 } | |
| 72 loader.requestNotify(notifiee); | |
| 73 } | |
| 74 | |
| 75 function nameFromUrl(url) { | |
| 76 return url.replace(/[\:\/\%\?\&\.\=\-\,]/g, '_') + '_api'; | |
| 77 } | |
| 78 | |
| 79 var Loader = function(name, url, callbackName) { | |
| 80 this.instances = []; | |
| 81 this.callbackName = callbackName; | |
| 82 if (this.callbackName) { | |
| 83 window[this.callbackName] = this.success.bind(this); | |
| 84 } else { | |
| 85 if (url.indexOf(this.callbackMacro) >= 0) { | |
| 86 this.callbackName = name + '_loaded'; | |
| 87 window[this.callbackName] = this.success.bind(this); | |
| 88 url = url.replace(this.callbackMacro, this.callbackName); | |
| 89 } else { | |
| 90 // TODO(sjmiles): we should probably fallback to listening to script.loa
d | |
| 91 throw 'core-shared-api: a %%callback%% parameter is required in the API
url'; | |
| 92 } | |
| 93 } | |
| 94 // | |
| 95 this.addScript(url); | |
| 96 }; | |
| 97 | |
| 98 Loader.prototype = { | |
| 99 | |
| 100 callbackMacro: '%%callback%%', | |
| 101 loaded: false, | |
| 102 | |
| 103 addScript: function(src) { | |
| 104 var script = document.createElement('script'); | |
| 105 script.src = src; | |
| 106 script.onerror = this.error.bind(this); | |
| 107 var s = document.querySelector('script'); | |
| 108 s.parentNode.insertBefore(script, s); | |
| 109 this.script = script; | |
| 110 }, | |
| 111 | |
| 112 removeScript: function() { | |
| 113 if (this.script.parentNode) { | |
| 114 this.script.parentNode.removeChild(this.script); | |
| 115 } | |
| 116 this.script = null; | |
| 117 }, | |
| 118 | |
| 119 error: function() { | |
| 120 this.cleanup(); | |
| 121 }, | |
| 122 | |
| 123 success: function() { | |
| 124 this.loaded = true; | |
| 125 this.cleanup(); | |
| 126 this.result = Array.prototype.slice.call(arguments); | |
| 127 this.instances.forEach(this.provide, this); | |
| 128 this.instances = null; | |
| 129 }, | |
| 130 | |
| 131 cleanup: function() { | |
| 132 delete window[this.callbackName]; | |
| 133 }, | |
| 134 | |
| 135 provide: function(instance) { | |
| 136 instance.notify(instance, this.result); | |
| 137 }, | |
| 138 | |
| 139 requestNotify: function(instance) { | |
| 140 if (this.loaded) { | |
| 141 this.provide(instance); | |
| 142 } else { | |
| 143 this.instances.push(instance); | |
| 144 } | |
| 145 } | |
| 146 | |
| 147 }; | |
| 148 | |
| 149 })(); | |
| 150 </script> | |
| 151 </polymer-element> | |
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