用eggjs的看过来，setToken getToken 的用法

[looping84]

要bind this，要不然，里边的this 指向的是oAuth

new OAuth(app.appid, app.secret, ctx.service.wechat.getToken.bind(this), ctx.service.wechat.setToken.bind(this), true);

// service/wechatToken.js

async getToken(openid) {
    const res = await this.ctx.model.WechatToken.findOne({ openid });
    return res;
  }

  async setToken(openid, token) {
    // 有则更新，无则添加
    var query = { openid: openid };
    var options = { upsert: true };

    await this.ctx.model.WechatToken.update(query, token, options);
  }