如何在 express.js 中的路由之间传递数据

Question

希望有人可以帮助我。找不到解决办法。也许我也只是走错路了？ 这是一个简单的快速设置，我很新。 我从请求中得到响应，并希望将响应中的变量/数据传递到下一个路由到 URL。 因此，根据第一次调用的响应，下一个 URL 中的一个参数应该是动态的。

这里是我的全部代码：

我的问题是你可以在哪里看到 const sendoutID

const express = require("express");
const app = express();
const request = require("request");
const bodyParser = require("body-parser");
const port = 3001;

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));




// Create Sendout
app.post("/createSendout", (req, res, next) => {
  request.post(
    {
      url: "https://www.something.com/api/v1.2/surveys/904211/sendouts",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxx-xxx-xxxx-xxx-xxxxxxx",
      },
    },
    function (error, response, body) {
      console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results.CreateSendoutResult.SendoutId); // View Results

// I want this data "results.CreateSendoutResult.SendoutId" passing to the next route

       
      }
    }
  );
});


/* here the variable is just hard coded for now but 
I want to pass it in the URL from my previous route 
to the next route see below at + sendoutID +..*/

const sendoutId = 389125;


// Add Respondent
app.post("/addRespondent", (req, res, next) => {
  request.post(
    {
      url:
        "https://www.something.com/api/v1.2/surveys/904211/sendouts/" +
        sendoutId +
        "/respondents",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxxxx-xxx-xxx-xxx-xxxxxxxx",
      },
    },
    function (error, response, body) {
      console.log(response);
      //console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results); // View Results
      }
    }
  );
});


app.listen(port, () => {
  console.log(`app listening at http://localhost:${port}`);
});

Answer 1

1. 要传递到下一条路线，您可以将results.CreateSendoutResult.SendoutId 分配给req.body

   req.body.SendoutId = results.CreateSendoutResult.SendoutId;

然后你可以在下一个路由中使用该 SendoutId。

1. 您可以在 next() 中传递该变量

   下一个(results.CreateSendoutResult.SendoutId);

在下一条路线中，您可以通过调用来访问它：

function nextRoute(SenderId, req, res, next)

已编辑：

const express = require("express");
const app = express();
const request = require("request");
const bodyParser = require("body-parser");
const port = 3001;

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));




// Create Sendout
app.post("/createSendout", (req, res, next) => {
  request.post(
    {
      url: "https://www.something.com/api/v1.2/surveys/904211/sendouts",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxx-xxx-xxxx-xxx-xxxxxxx",
      },
    },
    function (error, response, body) {
      console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results.CreateSendoutResult.SendoutId); // View Results

// I want this data "results.CreateSendoutResult.SendoutId" passing to the next route

      req.SendoutId = results.CreateSendoutResult.SendoutId;
       
      }
    }
  );
}, addRespondent);


/* here the variable is just hard coded for now but 
I want to pass it in the URL from my previous route 
to the next route see below at + sendoutID +..*/

const sendoutId = 389125;


// Add Respondent
app.post("/addRespondent", addRespondent);

function addRespondent(req, res, next) => {
  request.post(
    {
      url:
        "https://www.something.com/api/v1.2/surveys/904211/sendouts/" +
        req.sendoutId +
        "/respondents",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxxxx-xxx-xxx-xxx-xxxxxxxx",
      },
    },
    function (error, response, body) {
      console.log(response);
      //console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results); // View Results
      }
    }
  );
}


app.listen(port, () => {
  console.log(`app listening at http://localhost:${port}`);
});

Answer 2

1. 您应该使用中间件函数。

什么是中间件函数？

-> 它只是一个在中间运行的函数，即（在请求到达路由之前并在请求完成之前结束。Express Documentation for writing middlewares.

中间件函数是可以访问请求对象 (req)、响应对象 (res) 和下一个函数的函数。注意中间件函数不会结束请求-响应循环，它必须调用 next() 将控制权传递给下一个中间件函数。否则，请求将被挂起。。

使用中间件功能的优势 ->“您以后也可以将此功能用于任何其他请求”，在其他模块中使用它。

2)

const captureSendOutIDMiddleware = async (req, res, next) => {
    try {
         req.SendOutID=results.CreateSendoutResult.SendoutId; //changed "const req" to just req.
             next();

    } catch (error) {
        res.status(401).send({
            error: 'NO SEND OUT ID'
        })
    }
app.post("/CreateSendOut",captureSendOutIDMIddleware,async(req, res) =>{
//do your operation

});

app.post("/addRespondent",async(req,res)=>{

const capturedSendoutID=req.SendoutID;
console.log(capturedSendoutID);
//do you operations

});

Answer 3

感谢您的帮助。 我现在找到了另一个解决方案，它和我发现另一个问题一样有效。不知道这是否也是它不起作用的原因，或者您的解决方案不起作用的原因。但我使用 app.set() 和 app.get 来传递数据。 另一个问题是，现在使用 app.set() 和 app.get() 有时可以工作，有时不能。所以我在前端的调用上设置了一个超时，它执行 api 请求。只是之间有一点时间。 这是我的新代码

// Create Sendout
app.post("/createSendout", (req, res, next) => {
  request.post(
    {
      url: "https://www.something.com/api/v1.2/surveys/904211/sendouts",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxxxx-xxx-xx-xxxx-xxxxx",
      },
    },
    function (error, response, body) {
      console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results.CreateSendoutResult.SendoutId); // View Results
        app.set("surveyId", results.CreateSendoutResult.SendoutId);    // new added line
      }
    }
  );
});


// Add Respondent
app.post("/addRespondent", (req, res, next) => {
  const surveyId = app.get("surveyId");        // new added line
  request.post(
    {
      url:
        "https://www.something.com/api/v1.2/surveys/904211/sendouts/" +
        surveyId +
        "/respondents",
      body: JSON.stringify(req.body),
      headers: {
        "Content-Type": "application/json",
        "X-API-KEY": "xxxxxx-xxx-xxxx-xxxx-xxxxxxxx",
      },
    },
    function (error, response, body) {
      console.log(response);
      //console.log(response.statusCode);
      if (!error && response.statusCode == 200) {
        // Successful call
        var results = JSON.parse(body);
        console.log(results); // View Results
      }
    }
  );
});