I am trying to implement some middleware in Express that should be called for all routes. This middleware should alter the request object.
I've tried several things already but seem to keep having the same issue. Soon as the middleware is left it looks like the request object is changed back to it's original state.
Currently my code resembles (I simplified it with a minimalistic example):
route.js:
const express = require('express');
const router = express.Router();
router.get('/getMe', (req, res) => {
// return the desired data.
// I expect req.params.myString to exist here but it does not.
});
module.exports = router;
index.js:
const express = require('express');
const router = express.Router();
router.use('/', require('./route'));
module.exports = router;
app.js:
const express = require('express');
const app = express();
const routes = require('./index');
app.use((req, res, next) => {
// Adding req.params.myString to the request object.
if (req.params.myString === undefined) req.params.myString = 'hello world';
next();
});
app.use('/api', routes);
As you can see I left out some of the code to keep it more readable. This is the code that gets the response and sets up the server.
Again, I am expecting that req.params.myString becomes available in the endpoint. Does anyone see what I am doing wrong?
In express docs ( http://expressjs.com/en/api.html#req.params ) it says:
If you need to make changes to a key in req.params, use the app.param
handler. Changes are applicable only to parameters already defined in
the route path.
So you need to check app.param handler.
http://expressjs.com/en/4x/api.html#app.param
You should app.set("myString", "hello World") inside your app.js and then you can access the field in your route.js/index.js scripts by using req.app.get("myString"). Or this should work too, set it like app.myString = "Hello world" and access it like req.app.myString.
Related
I can't figure out why my route 'scrape will not render. I have tried everything I can think of, even changing everything to a very basic route and I just cannot get anything to work.
app.js
const indexRoute = require("./routes/index");
const scrapeRoute = require("./routes/scrape");
// view engine setup
app.set("views", path.join(__dirname, "views"));
app.set("view engine", "ejs");
app.use(cors());
app.use(express.json());
app.use(express.urlencoded({ extended: false }));
app.use(cookieParser());
app.use(express.static(path.join(__dirname, "public")));
app.use(logger("dev"));
// Routes
app.use("/", indexRoute);
app.use("/scrape", scrapeRoute);
module.exports = app;
here is the route:
const express = require("express");
const router = express.Router();
router.post("/", (req, res) => {
res.send(req.body);
});
module.exports = router;
the index route works just fine. for some reason the route 'scrape' just will not work. I had logic in there to scrape a website but when that wasn't working I figured I'd change it to just a basic route to see if I'm even getting anything and now it's just sending a 404 when I go to localhost:9000/scrape
If you're just going to http://localhost:9000/scrape in the browser, then that is a GET request, not a POST request. And, you would need:
const express = require("express");
const router = express.Router();
router.get("/", (req, res) => {
res.send("hello");
});
module.exports = router;
To get a response from that - change to router.get(). And, because it's a GET request, there is no body so req.body would predictably be empty for a GET request.
To send a POST request from a browser, you either need have the browser submit a form with method="POST" and action="/scrape" as a attributes of the <form> tag or you need to use Ajax to programmatically send a POST request from Javascript using the fetch() interface or the XMLHttpRequest interface.
Are you sure you are making a post call from the client?
I'm trying to combine puppeter-extra with express. For each request I will be able to load a different plugin, for example:
const puppeteer = require("puppeteer-extra");
const StealthPlugin = require("puppeteer-extra-plugin-stealth");
const router = express.Router();
router.get("/", async (req, res) => {
const { useStealth } = req.query
if(useStealth) puppeteer.use(StealthPlugin());
const browser = await puppeteer.launch(parameters..)
const page = await browser.newPage();
})
The problem is that, when I send the first request with query useStealth, it will set in node cache puppeteer-extra to use StealthPlugin, so the others next requests will use it. I tried to solve this problem by clear node cache, it works but it's a problem for concorrent requests. My code to try to solve it (But it has the concorrent request problem):
delete require.cache[require.resolve('puppeteer-extra')];
puppeteer = require('puppeteer-extra');
Is there anyway to clean puppeteer.use function ? (So, It would be a new instance of puppeteer-extra per request)
Thanks!
I tried to create the simplest test route to test on my localhost as follows.
Verified localhost:3000 is up. Wrote a simple test file.
const express = require('express');
const router = express.Router();
router.route('/test').get((req, res) => {
console.log('route found');
});
module.exports = router;
My routes are split up as follows in my index routing file in the routes directory.
module.exports.api = require('./api');
module.exports.auth = require('./auth');
module.exports.root = require('./root');
module.exports.articles = require('./articles');
module.exports.test = require('./test');
I use the route as follows in my index.js for the server:
const routes = require(__dirname + '/routes');
app.use('/test', routes.test);
Tested it using Postman.
Sent request to localhost:3000/test/test.
No response. How can I troubleshoot further?
You are not getting any response because you are not sending any response from the server. You need to send some response back otherwise the client will keep waiting for the response until request times out.
router.route('/test').get((req, res) => {
res.send('route not found');
});
Edit
app.use('/test', routes.test); won't work with the way your route is defined. For it to work, request url should be /test/test. If you want request url to be just /test, change
app.use('/test', routes.test);
to
app.use(routes.test);
Here's a working version of what you want to do
const express = require('express');
const router = express.Router();
router.get('/test', (req, res) => {
res.send("hey");
console.log('route found');
});
module.exports = router;
Now in your main module, you need to check that you're listening to the right port, and that your express app is actually using the exported router!
const express = require('express');
const app = express();
const router = require('path/to/router/module');
app.use(router)
app.listen(8080, () => console.log("listening to port 8080"));
EDIT:
You mentioned that
My routes are split up as follows in my index routing file in the routes directory.
And, I can see that in the main module, you are requiring the directory itself, and not the routes module
const routes = require(__dirname + '/routes');
while what you should require is a module and not a directory!
const routes = require(__dirname + '/routes/yourRouteModuleName');
The solution I just gave assumes the following project's structure:
├── index.js
├── routes
│ ├── test.js
│ ├── routeModuleOrWhatever.js
│
Here are my routes:
app.get('/signUp', routes.signUp);
app.post('/signUp' , routes.signUp);
Here is my separate file for routes.
exports.signUp = function(req, res) {
res.render('signUp');
};
The second block of code is behaviour I want in response to a get request.
How do I respond to a post request? I have already tied up the signUp function with behaviour that responds to get. Do I bundle up the post behaviour in the same function and render the sign up page again? Suppose I simply want to render the view, I don't want the post behaviour to execute in that case so it would be strange to bundle those together.
I believe the express router module should resolve this for you.
route file -
var express = require('express');
var router = express.Router();
router.route("/")
.get(function (req, res) {
res.render('signUp');
})
.post(function (req, res) {
//do something else
})
module.exports = router
index.js/app.js/server.js/whatever you call it.
//..
signUp = require("./routes/signup.js"); //or wherever this is
//...
app.use("/signUp", signUp);
//..
quick question regarding using React-Router. I'm having trouble getting my server to handle pushState (if this is the correct term). Originally, I was using a module called connect-history-api-fallback, which was a middleware that enabled me to only server up static files form my dist directory. Visiting the client www.example.com obviously worked and I could navigate throughout the site, additionally, refreshing at any route like www.example.com/about - could also work.
However, I recently added one simple API endpoint on my Express server for the React app/client to ping. The problem now is that while I can get the initial page load to work (and thus the /api/news call to work, to fetch data from a remote service), I can no longer do a refresh on any other routes. For example, now going to www.example.com/about will result in a failed GET request for /about. How can I remediate this? Really appreciate the help! PS - not sure if it matters, but I'm considering implementing Server Side Rendering later on.
import express from 'express';
import historyApiFallback from 'connect-history-api-fallback';
import config from '../config';
import chalk from 'chalk';
import fetch from 'node-fetch';
import path from 'path';
const app = express();
// FIXME: Unsure whether or not this can be used.
// app.use(historyApiFallback({
// verbose : true
// }));
//// DEVELOPMENT MODE ONLY - USING EXPRESS + HMR ////
/* Enable webpack middleware for hot module reloading */
if (config.get('globals').__DEV__) {
const webpack = require('webpack');
const webpackConfig = require('../build/webpack/development_hot');
const compiler = webpack(webpackConfig);
app.use(require('./middleware/webpack-dev')({
compiler,
publicPath : webpackConfig.output.publicPath
}));
app.use(require('./middleware/webpack-hmr')({ compiler }));
}
//// PRODUCTION MODE ONLY - EXPRESS SERVER /////
if (config.get('globals').__PROD__) {
app.use(express.static(__dirname + '/dist'));
}
//// API ENDPOINTS FOR ALL ENV ////
app.get('/api/news', function (req, res) {
fetch('http://app-service:5000/news')
.then( response => response.json() )
.then( data => res.send(data) )
.catch( () => res.sendStatus(404) );
});
// Wildcard route set up to capture other requests (currently getting undexpected token '<' error in console)
app.get('*', function (req, res) {
res.sendFile(path.resolve(__dirname, '../dist', 'index.html'));
});
export default app;
Express works by implementing a series of middleware that you "plug in" in order via .use. The cool thing is your routes are also just middlware — so you can separate them out, have them before your history fallback, and then only requests that make it past your routes (e.g., didn't match any routes) will hit the fallback.
Try something like the following:
const app = express();
// ...
var routes = exprss.Router();
routes.get('/api/news', function (req, res) {
fetch('http://app-service:5000/news')
.then( response => response.json() )
.then( data => res.send(data) )
.catch( () => res.sendStatus(404) );
});
app.use(routes);
app.use(historyApiFallback({
verbose : true
}));