I know it's possible to get data sent by the user in the back-end using Express.js which is:
router.get("/pathName", async function(req, res){
count = req.body;
})
But how to do this in vanilla (pure) Node.js itself?
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1nodejs.dev/learn/get-http-request-body-data-using-nodejsBarmar– Barmar2022-05-21 00:33:02 +00:00Commented May 21, 2022 at 0:33
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2Why? What are you trying to do that makes "using express" (or any other established web server framework) not an option? Node might have http/https APIs available, but they're just the http/https parts, and writing a web server on top of those is neither trivial, nor smart.Mike 'Pomax' Kamermans– Mike 'Pomax' Kamermans2022-05-21 00:33:37 +00:00Commented May 21, 2022 at 0:33
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I am just a beginner, and I wanna learn Node Js for it to be easy to master other node frameworks. That's why I try to build some simple projects in Node Jsuser16421569– user164215692022-05-21 00:38:18 +00:00Commented May 21, 2022 at 0:38
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1Does this answer your question? How is an HTTP POST request made in node.js?ricklink– ricklink2022-05-21 00:39:58 +00:00Commented May 21, 2022 at 0:39
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express is just a js library go look at the source code to see how they do it.Jared Smith– Jared Smith2022-05-21 01:02:48 +00:00Commented May 21, 2022 at 1:02
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1 Answer
Here's an example of a simple server.
const http = require('http');
http
.createServer((req, res) => {
res.writeHead(200, {
'Content-Type': 'text/html',
});
switch (req.url) {
// http://localhost:8080/
case '/':
res.write('<h1>Home</h1>');
break;
// http://localhost:8080/page
case '/page':
res.write('<h1>Page</h1>');
break;
}
res.end();
})
.listen(8080);
Also, here's an example (probably incomplete in terms of all edge cases...) of getting JSON data from a request payload:
const http = require("http");
// server that only supports POST /count
// expects JSON data to be passed like { "count": 100 }
// must have application/json content type header and POST method
http
.createServer(async (req, res) => {
// ensure method is content type json, POST, and /count
if (
req.headers["content-type"] != "application/json" ||
req.url !== "/count" ||
req.method !== "POST"
) {
res.writeHead(404, {
"Content-Type": "application/json",
});
res.write(JSON.stringify({ message: "Unsupported route" }));
res.end();
}
// try to read body
let body;
try {
body = await readBody(req);
} catch (err) {
res.writeHead(400, {
"Content-Type": "application/json",
});
res.write(JSON.stringify({ message: err.message }));
res.end();
}
// try to parse body
let parsedBody;
try {
parsedBody = JSON.parse(body);
} catch (err) {
res.writeHead(400, {
"Content-Type": "application/json",
});
res.write(JSON.stringify({ message: err.message }));
res.end();
}
// make sure count property is present in parsed body
if (typeof parsedBody.count === "undefined") {
res.writeHead(400, {
"Content-Type": "application/json",
});
res.write(JSON.stringify({ message: err.message }));
res.end();
}
// create response
res.writeHead(200, {
"Content-Type": "application/json",
});
res.write(JSON.stringify({ message: "Got " + parsedBody.count }));
res.end();
})
.listen(8080);
function readBody(req) {
return new Promise((res, rej) => {
let body = "";
req.on("data", (data) => {
body += data;
});
req.on("end", () => {
res(body);
});
req.on("error", (err) => {
rej(err);
});
});
}
Cool to see how it works for learning. But if you're using it for a project, I'd highly recommend Express or another framework/lib as you'll find it will get quite painful to try to consider all various cases you will need. Frameworks like Express are quite light anyway.
