100 lines
4.1 KiB
JavaScript
100 lines
4.1 KiB
JavaScript
require('../../fetch');
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import crypto from 'crypto';
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import { Buffer } from 'buffer';
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export class WechatWebInstance {
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appId;
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appSecret;
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accessToken;
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refreshAccessTokenHandler;
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externalRefreshFn;
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constructor(appId, appSecret, accessToken, externalRefreshFn) {
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this.appId = appId;
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this.appSecret = appSecret;
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this.externalRefreshFn = externalRefreshFn;
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if (!appSecret && !externalRefreshFn) {
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throw new Error('appSecret和externalRefreshFn必须至少支持一个');
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}
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if (accessToken) {
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this.accessToken = accessToken;
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}
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else {
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this.refreshAccessToken();
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}
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}
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async getAccessToken() {
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while (true) {
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if (this.accessToken) {
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return this.accessToken;
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}
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await new Promise((resolve) => setTimeout(() => resolve(0), 500));
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}
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}
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async access(url, mockData, init) {
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if (process.env.NODE_ENV === 'development') {
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return mockData;
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}
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const response = await global.fetch(url, init);
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const { headers, status } = response;
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if (![200, 201].includes(status)) {
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throw new Error(`微信服务器返回不正确应答：${status}`);
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}
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const contentType = headers['Content-Type'] || headers.get('Content-Type');
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if (contentType.includes('application/json')) {
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const json = await response.json();
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if (typeof json.errcode === 'number' && json.errcode !== 0) {
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if ([40001, 42001].includes(json.errcode)) {
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return this.refreshAccessToken();
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}
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throw new Error(`调用微信接口返回出错，code是${json.errcode}，信息是${json.errmsg}`);
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}
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return json;
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}
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if (contentType.includes('text') ||
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contentType.includes('xml') ||
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contentType.includes('html')) {
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const data = await response.text();
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return data;
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}
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if (contentType.includes('application/octet-stream')) {
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return await response.arrayBuffer();
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}
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return response;
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}
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async code2Session(code) {
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const result = await this.access(`https://api.weixin.qq.com/sns/oauth2/access_token?appid=${this.appId}&secret=${this.appSecret}&code=${code}&grant_type=authorization_code`, { session_key: 'aaa', openid: code, unionid: code });
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const { session_key, openid, unionid } = typeof result === 'string' ? JSON.parse(result) : result; // 这里微信返回的数据有时候竟然是text/plain
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return {
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sessionKey: session_key,
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openId: openid,
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unionId: unionid,
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};
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}
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async refreshAccessToken(url, init) {
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const result = this.externalRefreshFn ? await this.externalRefreshFn(this.appId) : await this.access(`https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=${this.appId}&secret=${this.appSecret}`, { access_token: 'mockToken', expires_in: 600 });
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const { access_token, expires_in } = result;
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this.accessToken = access_token;
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// 生成下次刷新的定时器
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this.refreshAccessTokenHandler = setTimeout(() => {
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this.refreshAccessToken();
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}, (expires_in - 10) * 1000);
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if (url) {
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return this.access(url, init);
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}
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}
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decryptData(sessionKey, encryptedData, iv, signature) {
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const skBuf = Buffer.from(sessionKey, 'base64');
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// const edBuf = Buffer.from(encryptedData, 'base64');
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const ivBuf = Buffer.from(iv, 'base64');
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const decipher = crypto.createDecipheriv('aes-128-cbc', skBuf, ivBuf);
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// 设置自动 padding 为 true，删除填充补位
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decipher.setAutoPadding(true);
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let decoded = decipher.update(encryptedData, 'base64', 'utf8');
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decoded += decipher.final('utf8');
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const data = JSON.parse(decoded);
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if (data.watermark.appid !== this.appId) {
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throw new Error('Illegal Buffer');
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}
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return data;
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}
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}
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