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| 1 | +var inherits = require('util').inherits; |
| 2 | +var EventEmitter = require('events').EventEmitter; |
| 3 | +var urllib = require('urllib'); |
| 4 | +var util = require('./util'); |
| 5 | +var wrapper = util.wrapper; |
| 6 | + |
| 7 | +var AccessToken = function (accessToken, expireTime) { |
| 8 | + if (!(this instanceof AccessToken)) { |
| 9 | + return new AccessToken(accessToken, expireTime); |
| 10 | + } |
| 11 | + this.accessToken = accessToken; |
| 12 | + this.expireTime = expireTime; |
| 13 | +}; |
| 14 | + |
| 15 | +/** |
| 16 | + * 检查AccessToken是否有效,检查规则为当前时间和过期时间进行对比 |
| 17 | + * |
| 18 | + * Examples: |
| 19 | + * ``` |
| 20 | + * api.isAccessTokenValid(); |
| 21 | + * ``` |
| 22 | + */ |
| 23 | +AccessToken.prototype.isValid = function () { |
| 24 | + return !!this.accessToken && (new Date().getTime()) < this.expireTime; |
| 25 | +}; |
| 26 | + |
| 27 | +/** |
| 28 | + * 根据appid和appsecret创建API的构造函数 |
| 29 | + * |
| 30 | + * Examples: |
| 31 | + * ``` |
| 32 | + * var API = require('wechat').API; |
| 33 | + * var api = new API('appid', 'secret'); |
| 34 | + * api.on('token', function (token) { |
| 35 | + * // 请将token存储到全局,跨进程级别的全局 |
| 36 | + * // 比如写到数据库、redis等 |
| 37 | + * // 这样才能在cluster模式下使用 |
| 38 | + * }); |
| 39 | + * // 或者 |
| 40 | + * getTokenFromGlobal(function (token) { |
| 41 | + * // var api = new API('appid', 'secret', token); |
| 42 | + * }); |
| 43 | + * ``` |
| 44 | + * @param {String} appid 在公众平台上申请得到的appid |
| 45 | + * @param {String} appsecret 在公众平台上申请得到的app secret |
| 46 | + * @param {Object} token 可选的。全局token对象,该对象在调用一次`getAccessToken`后得到 |
| 47 | + */ |
| 48 | +var API = function (appid, appsecret, token) { |
| 49 | + this.appid = appid; |
| 50 | + this.appsecret = appsecret; |
| 51 | + if (token) { |
| 52 | + this.token = AccessToken(token.accessToken, token.expireTime); |
| 53 | + } |
| 54 | + this.prefix = 'https://api.weixin.qq.com/cgi-bin/'; |
| 55 | + this.mpPrefix = 'https://mp.weixin.qq.com/cgi-bin/'; |
| 56 | + this.fileServerPrefix = 'http://file.api.weixin.qq.com/cgi-bin/'; |
| 57 | + this.payPrefix = 'https://api.weixin.qq.com/pay/'; |
| 58 | + EventEmitter.call(this); |
| 59 | +}; |
| 60 | +inherits(API, EventEmitter); |
| 61 | + |
| 62 | +/** |
| 63 | + * 根据创建API时传入的appid和appsecret获取access token |
| 64 | + * 进行后续所有API调用时,需要先获取access token |
| 65 | + * 详细请看:<http://mp.weixin.qq.com/wiki/index.php?title=获取access_token> |
| 66 | + * |
| 67 | + * Examples: |
| 68 | + * ``` |
| 69 | + * api.getAccessToken(callback); |
| 70 | + * ``` |
| 71 | + * Callback: |
| 72 | + * |
| 73 | + * - `err`, 获取access token出现异常时的异常对象 |
| 74 | + * - `result`, 成功时得到的响应结果 |
| 75 | + * |
| 76 | + * Result: |
| 77 | + * ``` |
| 78 | + * {"access_token": "ACCESS_TOKEN","expires_in": 7200} |
| 79 | + * ``` |
| 80 | + * @param {Function} callback 回调函数 |
| 81 | + */ |
| 82 | +API.prototype.getAccessToken = function (callback) { |
| 83 | + var that = this; |
| 84 | + var url = this.prefix + 'token?grant_type=client_credential&appid=' + this.appid + '&secret=' + this.appsecret; |
| 85 | + urllib.request(url, {dataType: 'json'}, wrapper(function (err, data) { |
| 86 | + if (err) { |
| 87 | + return callback(err); |
| 88 | + } |
| 89 | + // 过期时间,因网络延迟等,将实际过期时间提前10秒,以防止临界点 |
| 90 | + var expireTime = (new Date().getTime()) + (data.expires_in - 10) * 1000; |
| 91 | + that.token = AccessToken(data.access_token, expireTime); |
| 92 | + that.emit('token', that.token); |
| 93 | + callback(err, that.token); |
| 94 | + })); |
| 95 | + return this; |
| 96 | +}; |
| 97 | + |
| 98 | +/** |
| 99 | + * 需要access token的接口调用如果采用preRequest进行封装后,就可以直接调用 |
| 100 | + * 无需依赖getAccessToken为前置调用 |
| 101 | + * |
| 102 | + * @param {Function} method 需要封装的方法 |
| 103 | + * @param {Array} args 方法需要的参数 |
| 104 | + */ |
| 105 | +API.prototype.preRequest = function (method, args) { |
| 106 | + var that = this; |
| 107 | + var callback = args[args.length - 1]; |
| 108 | + if (that.token && that.token.isValid()) { |
| 109 | + method.apply(that, args); |
| 110 | + } else { |
| 111 | + that.getAccessToken(function (err, data) { |
| 112 | + // 如遇错误,通过回调函数传出 |
| 113 | + if (err) { |
| 114 | + callback(err, data); |
| 115 | + return; |
| 116 | + } |
| 117 | + method.apply(that, args); |
| 118 | + }); |
| 119 | + } |
| 120 | +}; |
| 121 | + |
| 122 | +/** |
| 123 | + * 用于支持对象合并。将对象合并到API.prototype上,使得能够支持扩展 |
| 124 | + * Examples: |
| 125 | + * ``` |
| 126 | + * // 媒体管理(上传、下载) |
| 127 | + * API.mixin(require('./lib/api_media')); |
| 128 | + * ``` |
| 129 | + * @param {Object} obj 要合并的对象 |
| 130 | + */ |
| 131 | +API.mixin = function (obj) { |
| 132 | + for (var key in obj) { |
| 133 | + if (obj.hasOwnProperty(key)) { |
| 134 | + if (API.prototype.hasOwnProperty(key)) { |
| 135 | + throw new Error('Don\'t allow override existed prototype method.'); |
| 136 | + } |
| 137 | + API.prototype[key] = obj[key]; |
| 138 | + } |
| 139 | + } |
| 140 | +}; |
| 141 | + |
| 142 | +module.exports = API; |
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