Node.js: HTTP/2 server setup

In this tutorial we will check how to setup a very simple HTTP/2 server using node.js. We will be using the HTTP/2 module to setup the server and a web browser as client.

Introduction

In this tutorial we will check how to setup a very simple HTTP/2 server using node.js. We will be using the HTTP/2 module to setup the server and a web browser as client. Upon receiving the request, the server will just return back a “Hello World” message to the client.

Note that you may need to update the node.js version for the HTTP/2 module to be available. I’ll be using version 11.6.0 of node.js.

One important thing to take in consideration is that currently no browser supports HTTP/2 without encryption [1][2], which means that we will need to configure our server to work over a secure connection (HTTPS).

This means that we will need to generate a testing server certificate (it will be self signed) and a private key. We will check how to do it on the next section.

The tests shown here were done on Windows 8.1.

Generating the certificates

Before generating the required certificate and private key, we need to install openssl. Only after that it will be possible to send the command needed to generate both. Explaining how to install openssl is outside of the scope of this post but there are plenty of sources available on the web that explain how to do it.

Once you install openssl, open a command line on your machine and send the command shown below. Note that this is the same command that is shown on the node.js HTTP/2 documentation server example.

openssl req -x509 -newkey rsa:2048 -nodes -sha256 -subj '/CN=localhost' -keyout localhost-privkey.pem -out localhost-cert.pem

After running the command, two files should have been created on the directory where you are located. They are named localhost-cert.pem and localhost-privkey.pem, as shown in figure 1.

Figure 1 – Created certificate and key.

Alternatively, in case you find any problems while generating the files or installing openssl, below is the content of both files. You just need to copy the content of each one and save them in files with the names and the extensions indicated before.

localhost-privkey.pem

localhost-cert.pem

The code

The code for this tutorial will be very simple. The first thing we are going to do is importing the modules needed for the code to work. The first module we are going to need is the HTTP/2 module, which will make available the HTTP/2 related functionality.

const http2 = require('http2');

Additionally, we will need to import the file system module, so we can read both our certificate and private key files.

const fs = require('fs');

Next, we will need to define a callback function that will be executed when a HTTP/2 request is received by the server.

This function will be invoked with two arguments: an object of class Http2ServerRequest and an object of class Http2ServerResponse.

The first object may be used to access the request status, headers, and data [1]. Nonetheless, we are not going to use it for this tutorial.

The second object allows to send data back to the client and we are going to use it to send a “Hello World” message as response of the request.

function onRequest (req, resp) {
// implementation
}

Now, in order to send the response to the client, we will simply call the end method on our Http2ServerResponse object.

We will pass as input of this method a string with the content we want to send back to the client. Note that, besides sending the data back to the client, this method is responsible for signaling that all the content was sent and the message should be considered complete [1].

function onRequest (req, resp) {
	resp.end("Hello World");
}

After this, we can create our server by calling the createSecureServer function of the HTTP/2 module. As first input, this function receives a JavaScript object representing some options and, as second input, it can optionally receive a callback function to handle a request received event.

Regarding the first parameter, for this simple tutorial, we will have to create an object with two attributes called key and cert. The first attribute value should correspond to the private key we have previously generated and the second attribute should correspond to the server certificate we also generated.

We can read both files by calling the readFileSync function of the file system module, passing as input the path to the file. Note that, in the code below, I’m assuming that both the .pem files and the JavaScript file are located in the same directory, which is why I’m simply passing the file names and not the whole paths.

Regarding the second parameter, we simply need to pass the onRequest callback function we have defined earlier.

This function will return a Http2SecureServer instance, which we will store on a variable.

const server = http2.createSecureServer({
  key: fs.readFileSync('localhost-privkey.pem'),
  cert: fs.readFileSync('localhost-cert.pem')
}, onRequest);

Finally, we will call the listen method on the server object, passing as input the number of the port where it should listen to incoming requests. We will be using port 8443.

server.listen(8443);

The final code can be seen below.

const http2 = require('http2');
const fs = require('fs');

function onRequest (req, resp) {
	resp.end("Hello World");
}

const server = http2.createSecureServer({
  key: fs.readFileSync('localhost-privkey.pem'),
  cert: fs.readFileSync('localhost-cert.pem')
}, onRequest);

server.listen(8443);

Testing the code

To test the code, simply run the previous script on a tool of your choice. I’ll be using Visual Studio Code with the Code Runner extension.

After running the code, open a web browser of your choice with HTTP/2 support. I’m using Google Chrome. Then, access the following URL:

https://localhost:8443/stream

Note that the “/stream” path is optional and we can use another one if we want, since we are not defining which routes are valid in our server. In other words, it means that our server will always answer no matter which route we try to access.

Since we are using a self signed certificate, the browser should complain about security issues. Simply choose to advance.

You should get an output similar to figure 2, which shows the message we defined on the code.

Figure 2 – Response sent back to the client.

References

[1] https://nodejs.org/api/http2.html

[2] https://http2.github.io/faq/#does-http2-require-encryption

Node.js: HTTP/2 server setup

Introduction

Generating the certificates

The code

Testing the code

References

4 thoughts on “Node.js: HTTP/2 server setup”

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Introduction

Generating the certificates

The code

Testing the code

References

4 thoughts on “Node.js: HTTP/2 server setup”

Leave a ReplyCancel reply

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