Question

我正在尝试使用javascript Promises在某些API上发出链式请求。在第一个函数我查询数据，我得到一个ID并返回它。在第二个函数，我得到第一个函数的ID，我查询更多的数据，在第三个函数，我发送到我的API。我的代码如下。

var express = require("express");
var app = express();
var FB = require("fb");
var request = require("request");
var Promise = require("promise");
var eventData = {};
var venueId, theUrl;

app.get("/writeEvents", function(req, res) {
  Promise.resolve(1)
    .then(() => {
      return Promise.resolve(req.query.eventID);
    })
    .then(value => {
      FB.options({ version: "v2.10" });
      FB.setAccessToken("sometoken");
      FB.api("" + value + "", { fields: eventFields }, function(results) {
        if (!results || results.error) {
          console.log(!results ? "error occurred" : results.error);
          return;
        }
        venueId = results.owner.id;
        console.log("first: " + venueId);
        //res.send(JSON.stringify(results, null, "    "));
        /*EVENT*/
        eventData["id"] = results.id;
        eventData["name"] = results.name;
      });
      return Promise.resolve(venueId);
    })
    .then(value => {
      FB.options({ version: "v2.10" });
      FB.setAccessToken("sometoken");
      console.log("second: " + value);
      FB.api("" + value + "", { fields: pageFields }, function(resPage) {
        if (!resPage || resPage.error) {
          console.log(!resPage ? "error occurred" : resPage.error);
          return;
        }

        /*VENUE*/
        eventData["venue"] = {};
        eventData["venue"]["id"] = resPage.id;
        eventData["venue"]["name"] = resPage.name;
      });
      return true;
    })
    .then(value => {
      var toJson = JSON.stringify(eventData, null, "    ");
      var parametrus = encodeURIComponent(toJson);
      theUrl = "https://example2.com?eventData=" + parametrus + "";
      res.send(
        JSON.stringify(eventData, null, "    ") + " the url : " + theUrl
      );
      request(theUrl, function(error, response, body) {
        console.log("error:", error); // Print the error if one occurred
        console.log("statusCode:", response && response.statusCode); // Print the response status code if a response was received
        console.log("body:", body); // Print the HTML for the Google homepage.
      });
      return Promise.resolve();
    })
    .catch(error => {
      console.log(error);
    });
});
app.listen(port);

当我在浏览器中点击example.com/writeEvents?eventID=1906888876040770

时

我在屏幕上打印了以下内容

{} the url : https://example2.com/writeEventsTwo?eventData=%7B%7D

在控制台

正如你所看到的......第二张照片是在第一张照片开始之前拍摄的！知道它失败的原因吗？

Javascript Promises链接函数，总是首先触发第二个函数

0 个答案: