forchange-api/lib/token-model.js

A sdk of forchange api.

const Promise = require('bluebird');
const APIs = require('st-api').APIs;
const HttpClient = require('st-api').HttpClient;
const StatusCode = require('./common/status-code');


class TokenModel {
	constructor(opts) {
		this.appid = opts.appid;
		this.secret = opts.secret;
		this.tokenExpires = opts.tokenExpires || 3600000;
		if (opts.api) {
			this.tokenApi = opts.api;
		} else {
			let config = {
				defaultHost: opts.host,
				token: {
					pathname: '/api/v1/auth',
					method: 'post',
					type: 'form'
				}
			};
			let apis = new APIs(config, new HttpClient());
			this.tokenApi = apis.token;
		}
		// 以下几个属性应当是私有，但 es6 class 不支持私有属性，所以暂时先这么写
		// 不要随意修改这几个属性!不要随意修改这几个属性!不要随意修改这几个属性!
		this.token = null;
		this.oldToken = null;
		this.lastUpdateTime = null;
		this.getToken();
		Object.defineProperties(this, {
			appid: {
				configurable: false,
				writable: false,
			},
			secret: {
				configurable: false,
				writable: false,
			},
			tokenExpires: {
				configurable: false,
				writable: false,
			},
			tokenApi: {
				configurable: false,
				writable: false,
			},
		});
	}

	isExpired() {
		const currentTime = (new Date())
			.getTime();
		return !this.token || this.lastUpdateTime + this.tokenExpires - 12000 <
			currentTime;
	}

	getToken() {
		if (this.isExpired()) {
			return this.tokenApi.post({
					appid: this.appid,
					secret: this.secret,
				})
				.then(data => {
					const dataObj = data;
					if (dataObj.error) {
						throw new Error(
							`An error occured when request token api: ${dataObj.error}`);
					} else if (dataObj.status_code === StatusCode.TOKEN_EXPIRED) {
						throw new Error(`Token has been expired: ${dataObj.message}`);
					}
					this.oldToken = this.token;
					this.token = dataObj.token;
					this.lastUpdateTime = (new Date())
						.getTime();
					return this.token;
				});
		}
		return Promise.resolve(this.token);
	}

	getOldToken() {
		return this.oldToken;
	}
}

module.exports = TokenModel;