POST and GET are two common HTTP Request used for building REST API’s. Both of these calls are meant for some special purpose.
As per the documentation GET request are meant to fetch data from specified resource and POST are meant to submit data to a specified resource.
Express allows you to handle GET and POST request using the instance of express. Due to the depreciation of connect middle-ware handling POST request however seems confusing to many people.
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GET request:
Handling GET request in Express seems so easy. You have to create instance of express and call get method. Here is small snippet to demonstrate that.
var app = express();
app.get('handle',function(request,response){
//code to perform particular action.
//To access GET variable use.
//request.var1, request.var2 etc
});
GET request can be cached and remains in browser history. This is why GET is not supposed to use for sensitive data (passwords, ATM pins, etc). GET are suppose to use to retrieve data only.
POST Request:
Express version 4 and above require extra middle-ware layer to handle a POST request. This middle-ware is called as ‘bodyParser’. This used to be an internal part of Express framework but now you have to install it separately.
You can install bodyParser by two way. Either by mentioning it in package.json or simply executing following command to download and put it in package file.
You have to import this package in your project and tell Express to use this as middle-ware. To do so here is a code.
var bodyParser = require("body-parser");
var app = express();
//Here we are configuring express to use body-parser as middle-ware.
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
Once configured you can use app.post express router to handle POST request. To access the POST query variable you can use request_variable.body.post_variable.
Here is a snippet to demonstrate the code.
var query1=request.body.var1;
var query2=request.body.var2;
});
In this way you can handle the GET and POST request in Express 4.
Demo App : Login System
To demonstrate this i am going to code one simple log-in System which will use GET request to serve HTML page to client and POST request from client to send user name and password to Server. So let’s create our package.json file.
"name": "get-post-demo",
"version": "0.0.1",
"dependencies": {
"body-parser": "^1.8.1",
"express": "^4.9.0"
}
}
Install dependencies using
Next we will create Express web Server.
var bodyParser = require("body-parser");
var app = express();
app.listen(3000,function(){
console.log("Started on PORT 3000");
})
Run Server using
We will use Express Router to handle routes of app. So when user request the app from web browser, we will serve the HTML file.
res.sendfile("index.html");
});
When user click on log-in button on HTML page we will POST request to Server and get the response.
var user_name=req.body.user;
var password=req.body.password;
console.log("User name = "+user_name+", password is "+password);
res.end("yes");
});
Here is complete Server code.
var bodyParser = require("body-parser");
var app = express();
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());
app.get('/',function(req,res){
res.sendfile("index.html");
});
app.post('/login',function(req,res){
var user_name=req.body.user;
var password=req.body.password;
console.log("User name = "+user_name+", password is "+password);
res.end("yes");
});
app.listen(3000,function(){
console.log("Started on PORT 3000");
})
On front-end we will create simple HTML file and call the POST request using Ajax. Here is a code of HTML page.
<head>
<title>Simple login</title>
<script src="//ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"> </script>
<script>
$(document).ready(function(){
var user,pass;
$("#submit").click(function(){
user=$("#user").val();
pass=$("#password").val();
$.post("http://localhost:3000/login",{user: user,password: pass}, function(data){
if(data==='done')
{
alert("login success");
}
});
});
});
</script>
</head>
<body>
<h1>Hello people !</h1>
<input type="TEXT" id="user" size="40"><br>
<input type="password" id="password" size="40"><br>
<input type="button" id="submit" value="Submit">
</body>
</html>
Here is a video of developing app.
That’s not a logging system.
No with session created, csrf token security, …
Hi,
This log-in system was just to demonstrate how to read POST data. I have explained Session too. Please see here.
plz try to solve this …http://stackoverflow.com/questions/33363617/in-mean-im-not-able-to-diplay-list-from-database-mongodb-into-angularjs
Thank you for nice, dedicated post!
what editor did you use there in the video?
Its Atom.
Thanks for this great information.
It is very helpful. Thanks
I got one question for you, do we need to hide our endpoint here to prevent anyone can send request to your server(/login) without going thru your client page? If so, what strategy should we use?
We can prevent IP to send request to our Server. If IP is from other than allowed network then it won’t accept the request. Please look over access-control and allow-origin headers parameters of HTTP.
Once again a resourceful post. Thanks!
However, I have a doubt. Will that alert get fired? Because, you are sending ‘yes’ as response and checking for ‘done’ in the html.
When I tried with specific ‘success’ function and compare with ‘yes’, it worked.
Please correct me if I am wrong.
U are right
Amazing post for using post.
Thanks dude!
But there is a mistake.
yes -> done
to fire alert();
little mistake
yse–>done
great post!!
Thanks men !!! 😀
You don’t really need sudo on that npm
Actually in my Ubuntu system i do need that.
It’s not really good practice to tell people to do that, though.
I cannot get this example to work. The req.body is returning undefined. Any ideas to help me please?
I’l love to help.
Are you using same code or you have done some modification ?
add this line: app.use(bodyParser.json());
Was that video suppose to be helpful ? It went way too fast
It was supposed to be demo of the code not tutorial video.
you require(Body-parser) yet you do not put it in your dependencies or tell anyone to install
i did put that in dependencies !
I cannot get this example to work from another computer.
If I run the server.js on machine 1 (which as an IP of say 10.45.32.102) and go to localhost:3000 everything works as expect.
However when I try to access this page from another computer (on the same network) by doing 10.45.32.102:3000 the Simple Login page shows up but when I hit the submit button It will not POST to the server. I don’t think the jquery is working in this particular instance could you help? The example is nice. But I want people from the network to be able to access the page.
Hi John,
I need to reproduce same scenario and come up with solution.
Stay tuned.
i open a connection using java httpurl connection and write data in output stream but
am not able to read input stream using node express. iam able to read using http module not in express
how to read request input stream using express4
If i had an array of items on my server that i wanted to search from the front end and have it return valid results how would i use post and get (or either) to do this? If search took a long time how would i tackle this?
You need to use POST cause you have to pass some data to SERVER. Pass the data, use indexOf() to search in array and if found return the value.
How to tackle if its slow ? If you get so much large data then you need to implement some search Algorithm like Binary search etc to improve the speed also update the SERVER configuration.
Thanks for sharing!
Other than body-parser module, are there any other modules for parsing the POST,PUT requests?
Hi author, I want the same thing but the slight change in that, In file I have only one POST API which server the response. The requesting is coming from another server.
Input is Json like :
{
name: ‘Veeresh’,
age:100
}
Output:
Just print input in browser.
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I am here now and would just like to say thanks a lot
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Thank you so much for appreciation.
Will keep it up (y)
Thank you for the tutorial, short but enough to get started.
Please look at this and advice me asap please I need it 4 my project .
Here’s how my login system works. I am using was as engine with /views as folder for views. I will skip lots of details
var router =express.Router();
…..
router.get(‘/’,fxn(req,res){
res.render(‘index’); //working
}
router. post(‘/login’, function(req,res){
console.log(‘test login’); //working
res.render(‘users/index’,{ some json data here }); // not working
}
Everything is well set so no working except the part for rendering a view after a post request. Maybe an example will help using express.Router()
Hi Brian,
Its seems to be a routing issue. Please verify the route you provided for the post method is correct.
Great simple example, thanks! Saved my day, wasn’t able to get those req params, thought that “body” usage dedicated to the html elements only…
very usefull
Getting Error : “ReferenceError: setImmediate is not defined”
Where did I use setImmediate ?
i want the code to store to form data into mongo database
can you see any reason why this Angular2 observable call would cause the same Express POST to crash?
public AddProject (body : string): Observable {
let bodyString = JSON.stringify(body); // Stringify payload
let headers
= new Headers({ ‘Content-Type’: ‘application/json’,
‘Accept’: ‘q=0.8;application/json;q=0.9’ }); // … Set content type to JSON
let options = new RequestOptions({ headers: this.headers });
return this.http.post(this.actionUrlnewProject, bodyString, options)
.map(response => response.json())
.catch(this.handleError);
}
Here is the Express code….
// Insert a new resume project
app.post(“/api/resume/newProject”, function(req, res) {
//for new projects we will calculate the uid
var uid = “2”; //req.param(‘uid’);
var name = req.body.name;
console.log(“req.body.name:”, req.body.name);
var year = req.body.year;
var note = req.body.note;
var type = req.body.type;
db.collection(“wr_project”).insert(
{
“uid”:uid,
“name”:name,
“year”:year,
“note”:note,
“type”:type
},
function(err, result) {
if(err) {
res.json(err);
res.end(“yes”);
};
res.json(result);
res.end(“yes”);
});
});
Can you paste the error trace? If it is “Headers already sent” then try to remove the res.end() from error and success block and put return in error block.
Thanks a lot – very good.
For those finding this article now and dont want to use jQuery this will do the same (in ‘newer browsers):
fetch(“localhost:3000/login”,
{
method: “POST”,
body: { user: “user”, password: “pass” }
});
hey can u plz help me with hapi.js for making api ..am new with it
How to go to next page when I click submit?
Will I be able to do the same with angular as front end also?