javascript - How to retrieve POST query parameters?

Here is my simple form:

    

        Email: 
        
    

Here is my Express.js/Node.js code:

app.post('/userlogin', function(sReq, sRes){    
    var email = sReq.query.email.;   
}

I tried sReq.query.email or sReq.query['email'] or sReq.params['email'], etc. None of them work. They all return undefined.

When I change to a Get call, it works, so .. any idea?

Answer

Things have changed once again starting Express 4.16.0, you can now use express.json() and express.urlencoded() just like in Express 3.0.

This was different starting Express 4.0 to 4.15:

$ npm install --save body-parser

and then:

var bodyParser = require('body-parser')
app.use( bodyParser.json() );       // to support JSON-encoded bodies
app.use(bodyParser.urlencoded({     // to support URL-encoded bodies
  extended: true
})); 

The rest is like in Express 3.0:

Firstly you need to add some middleware to parse the post data of the body.

Add one or both of the following lines of code:

app.use(express.json());       // to support JSON-encoded bodies
app.use(express.urlencoded()); // to support URL-encoded bodies

Then, in your handler, use the req.body object:

// assuming POST: name=foo&color=red            <-- URL encoding
//
// or       POST: {"name":"foo","color":"red"}  <-- JSON encoding

app.post('/test-page', function(req, res) {
    var name = req.body.name,
        color = req.body.color;

    // ...
});

---

Note that the use of express.bodyParser() is not recommended.

app.use(express.bodyParser());

...is equivalent to:

app.use(express.json());
app.use(express.urlencoded());
app.use(express.multipart());

Security concerns exist with express.multipart(), and so it is better to explicitly add support for the specific encoding type(s) you require. If you do need multipart encoding (to support uploading files for example) then you should read this.