How to pass data between routes in express.js - node.js

Question

hope someone can help me. Can't find a solution. Maybe I'm also just on the wrong way?
It's a simple express setup and I'm quite new.
I get a response from a request and want to pass a variable/the data from the response to the next route into the URL.
So one parameter in the next URL should be dynamical depending on the response of the first call.
here my whole code:
My problem is where you can see the 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

To pass to the next route you can assign results.CreateSendoutResult.SendoutId to req.body
req.body.SendoutId = results.CreateSendoutResult.SendoutId;
Then you can use that SendoutId in next route.
You can pass that variable inside next()
next(results.CreateSendoutResult.SendoutId);
In the next route you can access it by calling:
function nextRoute(SenderId, req, res, next)
Edited:
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

You should be using a middleware function.
What is a middleware function?
-> it's just a function that runs in the middle that is (before a request hits the route and ends before a request completes.Express Documentation for writing middlewares.
Middleware functions are functions that have access to the request object (req), the response object (res), and the next function.NOTE middleware function does not end the request-response cycle, it must call next() to pass control to the next middleware function. Otherwise, the request will be left hanging..
Advantage of using a middleware function -> "you can use this function for any other request too in the future", use it in other modules".
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

Thanks for your help.
I found now another solution which works as well as I found another issue. Don't know if it was also a cause for why it didn't work, or why your solutions didn't work. But I used app.set() and app.get to pass the data.
The other issue was, that now, with app.set() and app.get() it sometimes worked, sometimes not. So I set a timeout on the call in the frontend, which executes the api requests. Just to have a bit time between.
here is my new code
// 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
}
}
);
});