I'm taking a course on NodeJS, there were a few assignments related to routing, everything works fine except this part which seems a little odd: For some reason, I cannot read the parameter ID being passed to the mounted router.
dish.js
const express = require('express');
const bodyParser = require('body-parser');
const dishRouter = express.Router();
dishRouter.use(bodyParser.json());
dishRouter.route('/')
.all((req,res,next) => {
res.statusCode = 200;
res.setHeader('Content-Type','text/plain');
next();
})
.get((req,res) => {
console.info('Info: ',req);
res.end(`Sending details of the dish back to you: ${req.params.dishId}`);
})
.post((req,res) => {
res.statusCode = 403;
res.end(`Operation not supported: ${req.params.dishId}`);
})
.put((req,res) => {
res.write(`Updating the dish...: ${req.params.dishId} \n` );
res.end(`Will update this dish: ${req.body.name} with details: ${req.body.description}`);
})
.delete((req,res) => {
res.end(`Deleting this dish: ${req.params.dishId}`);
});
exports.dish = dishRouter;
dishes.js
const express = require('express');
const bodyParser = require('body-parser');
const dishesRouter = express.Router();
dishesRouter.use(bodyParser.json());
dishesRouter.route('/')
.all((req,res,next) => {
res.statusCode = 200;
res.setHeader('Content-Type','text/plain');
next();
})
.get((req,res) => {
res.end('Sending all dishes back to you');
})
.post((req,res) => {
res.end(`Will add the dish: ${req.body.name} with details: ${req.body.description}`);
})
.put((req,res) => {
res.statusCode = 403;
res.end(`Operation not supported.`);
})
.delete((req,res) => {
res.end(`Deleting all dishes.....`);
});
exports.dishes = dishesRouter;
index.js
const express = require('express');
const morgan = require('morgan');
const bodyParser = require('body-parser');
const http = require('http');
const dishRouter = require('./routes/dish');
const dishesRouter = require('./routes/dishes');
const hostname = 'localhost';
const port = 3000;
const app = express();
app.use(morgan('dev'));
app.use(bodyParser.json());
app.use('/dishes',dishesRouter.dishes);
app.use('/dishes/:dishId',dishRouter.dish);
app.use(express.static(__dirname+'/public'));
app.use((req,res,next) => {
res.statusCode = 200;
res.setHeader('Content-Type','text/html');
res.end('<html><body><h1>This is an Express Server</h1></body></html>');
});
const server = http.createServer(app);
server.listen(port,hostname,(req,res) => {
console.info(`Server running on port: ${port}, at: ${hostname}`);
})
This GET localhost:3000/dishes/123 is calling the right route, but the parameter dishId comes back as "undefined". Again, just learning nodeJS, seems like my receiver/mounted route should receive those parameters just fine, the body can be read properly, but not the params. ... thanks.
Yeah the params don't flow between routers. You're on a new router, hence new route params object.
You can check out the code for this: https://github.com/expressjs/express/blob/master/lib/router/index.js#L43 Check out line 43 and line 53 where route.params is set to an empty object.
Some examples:
index.js
app.use('/dishes/:dishId',(req, res) => {
console.log('now I get my dishId', req.params.dishId)
});
dish.js (version 1)
dishRouter.route('/')
.get((req, res) => {
console.log('now i get nothing', req.params)
})
dish.js (version 2)
dishRouter.route('/:anotherId')
.get((req, res) => {
console.log('now we get another parameter', req.params.anotherId)
})
// the path would be /dish/123/456
I'm not sure if there is a offical-expressjs-way to pass the params object between routers.
One solution would be to create a custom handler
index.js
app.use('/dishes/:dishId', handler)
handler.js
function handler (req, res, next) {
if (req.method === 'GET') {
console.log('now we get it', req.params)
}
}
module.exports = handler
Anoter way would be to add the dishId to the request object before calling the router:
index.js
app.use('/dishes/:dishId', (req, res, next) => {
req.dishId = req.params.dishId
router(req, res, next)
})
dish.js
const express = require('express')
const router = express.Router()
router.route('/')
.get((req, res) => {
console.log('nothing here', req.params)
console.log('dishId', req.dishId)
})
module.exports = router
Third way would be to send the params as options to a router function
index.js
app.use('/dishes/:dishId', (req, res, next) => {
router(req.params)(req, res, next)
})
dish.js
function createRouter (options) {
const router = express.Router()
router.route('/')
.get((req, res) => {
console.log('nothing here', req.params)
console.log('but alot here', options)
})
return router
}
module.exports = createRouter
If you want you could also just put the :dishId on the router as an optional parameter
index.js
app.use('/dishes', dishesRouter)
dishes.js
const express = require('express')
const router = express.Router()
router.route('/:dishId?')
.get((req, res) => {
if (req.params.dishId) {
res.end(`Sending details of the dish back to you: ${req.params.dishId}`)
} else {
res.end('Sending all dishes back to you');
}
})
module.exports = router