Hi I am facing the problem that I need to log each incomming request and the associated responses in my database. My current solution looks like the following:
./routes/customer.js
router.get('/', async (req, res, next) => {
req.allCustomers = await fetchAllCustomers();
res.status(200).send(req.allCustomers);
next(); // <- this is my personal problem
});
./middleware/logging.js
module.exports = function (req, res, next) {
db.query(
`INSERT INTO logging SET ?`,
{
request: JSON.stringify([req.body, req.params]),
response: JSON.stringify(req.response)
}
);
}
routes declaration
module.exports = function(app) {
app.use(express.json());
app.use('/api/customers', customers); // <- ROUTE ./routes/customer.js
app.use(logging); // <- MIDDLEWARE ./middleware/logging.js
}
I already mentioned my problem in my first piece of code. It is really repetitive to call next() in every route manually and I would like to avoid this. I already tried to load the middleware before all routes, call next() in the middleware function and execute my db query afterwards but I do not have the response at this point because of the async functionality.
Is there any way to handle this situation or will I need keep calling next() at the end of each route function?
If you don't want to call next() from your routes, you cannot have middleware run after them. It needs to be placed before. But can you get the response inside a middleware that runs before the route? The answer is yes!
It may be a little hacky, but since your route uses res.send(), you can use that to your advantage. By running before your route, your middleware can hijack that res.send function, to make it do other stuff.
./routes/customer.js
router.get('/', async (req, res, next) => {
req.allCustomers = await fetchAllCustomers();
res.send(req.allCustomers); // We'll hijack this
});
./middleware/logging.js
module.exports = function (shouldBeLoggedFunc) {
return function (req, res, next) {
if (shouldBeLoggedFunc(req)) {
// Store the original send method
const _send = res.send;
// Override it
res.send = function (body) {
// Reset it
res.send = _send;
// Actually send the response
res.send(body);
// Log it (console.log for the demo)
console.log(`INSERT INTO logging SET ?`, {
request: JSON.stringify([req.body, req.params]),
response: JSON.stringify(body)
});
};
}
next();
};
};
routes declaration
function shouldBeLogged(req) {
// Here, check the route and method and decide whether you want to log it
console.log(req.method, req.path); // e.g. GET /api/customers
return true;
}
module.exports = function(app) {
app.use(express.json());
app.use(logging(shouldBeLogged)); // <- Place this before your routes
app.use('/api/customers', customers);
};
when you use express.Router class like you already did and then use this code
app.use('/api/customers', customers);
you don't have to write 'next()' inside callback function in router.get .
there is an example
create a router file named birds.js in the app directory, with the following content:
var express = require('express')
var router = express.Router()
// middleware that is specific to this router
router.use(function timeLog (req, res, next) {
console.log('Time: ', Date.now())
next()
})
// define the home page route
router.get('/', function (req, res) {
res.send('Birds home page')
})
// define the about route
router.get('/about', function (req, res) {
res.send('About birds')
})
module.exports = router
Then, load the router module in the app:
var birds = require('./birds')
// ...
app.use('/birds', birds)
Related
How to set verification of session for all routes?
if(req.session.lang) req.session.lang
else req.session.lang = "pt";
const tradutor = require('../scripts/lang/lang-'+req.session.lang+'');
var traduPT = new tradutor();
this is my code. i want use for check in all routes, maybe something like adding the code and just applying the request on the routes, but how and where to do this code outside the routes?
You can create route-specific middleware.
// validate.js
export const validateSession = (req, res, next) => {
// if the user is logged in, continue
if (req.session.isLoggedIn) return next();
// otherwise, don't continue and go back to the /home route
res.redirect('/home');
};
Then pass it in as the second argument when defining your route:
// main.js
import { validateSession } from './validate.js';
app.get('/dashboard', validateSession, (req, res) => { /* ... */ });
app.get('/login', validateSession, (req, res) => { /* ... */ });
app.get('/foo', validateSession, (req, res) => { /* ... */ });
Normally, a function is passed as callback in app.use(), like so:
const express = require('express');
const app = express();
app.use(function (req, res, next) {
console.log('Time:', Date.now());
next();
});
In the case of node-expose-sspi however a method is passed:
const express = require('express');
const { sso } = require('node-expose-sspi');
const app = express();
app.use(sso.auth()); //stores something in req.sso
app.use((req, res, next) => {
res.json({
sso: req.sso,
});
});
Why is the method passed with ()? If it uses () why is it no called immediately (without arguments)?
Also, how can I wrap a method in a callback function, e.g.
app.use(myCallback);
function myCallback(req, res, next) {
sso.auth(); //req.sso is undefined
}
app.use(sso.auth());
calls sso.auth() and app.use()s its return value.
You can find over here in the node-expose-sspi source that .auth() indeed returns a new middleware function.
As for the second question
Also, how can I wrap a method in a callback function
you shouldn't do that – Express will call your used middlewares in order; a subsequent callback will have access to whatever a previous middleware has injected into the request.
If you for some reason really need to do that,
const ssoAuth = sso.auth();
function myCallback(req, res, next) {
ssoAuth(req, res, () => {
// whatever would regularly be in `myCallback`
next();
});
}
``
Assuming I have two routes one with params, one without:
/foo?bar
/foo
I want to use two different handlers for these two routes. I know I can do something like this.
app.use('/foo', (req, res) => {
if (req.params.foo !== undefined) {
// do something
} else {
// do something else
}
})
But, it would make the code harder to read. Is there a way to match a route that has a parameter? I would like to manage this situation:
app.use('/foo', x);
app.use('/foo?bar', y);
As far as I know, queries can not be filtered on use handler.
Instead, I made out with the very similar situation by using next.
app.use('/foo', (req, res, next) => {
if (req.query.foo !== undefined) return next();
//if foo is undefined, it will look for other matching route which will probably the next '/foo' route
/* things to do with foo */
});
app.use('/foo', (req, res) => {
//things to without foo
});
https://expressjs.com/en/guide/using-middleware.html
this document may also help you
How about this?
const express = require('express');
const app = express();
// curl -X GET http://localhost:3000/foo
app.get('/foo', function (req, res, next) {
res.send('This is foo');
});
// curl -X GET http://localhost:3000/foo/bar
app.get('/foo/:?bar', function (req, res, next) {
res.send('This is foo with bar');
});
app.listen(3000);
Trying to get URl parameters in express js,but got empty object.
var password= require('./routes/password');
app.use('/reset/:token',password);
password.js
router.get('/', function(req, res, next) {
console.log(req.params);
res.send(req.params);
});
console.log(req.params) output is {}
Access url :http://localhost:3000/reset/CiVv6U9HUPlES3i0eUsNwK9zb7xVZpfHsQNuzMNWqLlGA4NJKoagwbcyiUZ8
By default, nested routers do not get passed any parameters that are used in mountpaths from their parent routers.
In your case, app is the parent router, which uses /reset/:token as a mountpath, and router is the nested router.
If you want router to be able to access req.params.token, create it as follows:
let router = express.Router({ mergeParams : true });
Documented here.
You are getting params and query mixed up.
Query approach
Your code should look like this when using query values for the example url: www.example.com?token=123&foo=bar
router.get('/', function(req, res, next) {
console.log(req.query);
console.log(req.query.token); // to log value of token
console.log(req.query.foo); // to log value of foo
res.send(req.query);
});
Params approach
Your code should look like this when using params values for the example url: www.example.com/123
router.get('/:token', function(req, res, next) {
console.log(req.params);
console.log(req.params.token); // to log value of token
res.send(req.params);
});
Instead you can use a middleware to log the path params:
const logger = (req, res, next)=>{
console.log(req.params)
res.send(req.params)
next()//<----very important to call it.
};
app.use(logger); //<----use to apply in the app
router.get('/', (req, res, next)=>res.send('Logged.'));
Actually you messed it up a little bit. You have to pass instance of express to your module.
Server.js:
//adding modules
require('./routes/password')(app);
Password.js:
module.exports = function(router) {
router.get('/reset/:token', function(req, res, next) {
console.log(req.params);
res.send(req.params);
});
//and so on.. your routes go here
}
I'm using Nodejs and Expressjs and Kraken, I need to display message when added a product on index but I tried many time for to config but messages still not appear as I expect. Here is my config.js:
var flash = require('connect-flash');
app = module.exports = express();
app.use(kraken(options));
//flash
app.use(flash());
app.use(function (req, res, next) {
res.locals.messages = require('express-messages')(req, res);
next();
});
My controller :
router.post('/somePath', function (req, res) {
//something to do to add
res.flash('messages','Add success!!')
res.render('path/index');
});
My index.dust file:
`{>"layouts/master" /}
{<body}
{messages|s}
// body goes here
{/body}
`
You're pretty close to the answer.
This line
res.locals.messages = require('express-messages')(req, res);
Stores a function in messages that outputs the flash messages as an html fragment.
res.locals is merged by express with the models that are used to render your template.
Now you just need a way to invoke this function from within the dust template.
Doing this:
{messages|s}
Doesn't actually invoke the function. You need to call it as if it were a context helper:
{#messages /}
You'll have one last hurdle to clear.
The function signature that express-messages expects, is different from what dust provides, so you'll have to wrap it within a helper function (in your server.js file):
app.use(flash());
app.use(function (req, res, next) {
var messages = require('express-messages')(req, res);
res.locals.messages = function (chunk, context, bodies, params) {
return chunk.write(messages());
};
next();
});