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Node.js serverhttp2session.altsvc() Method

  • Last Updated : 06 Sep, 2021

The serverhttp2session.altsvc()  is  an inbuilt application programming interface of class serverhttp2session within http2 module which is used to submit an ALTSVC frame (as defined by RFC 7838) to the connected client.

Syntax:

const serverhttp2session.altsvc(alt, originOrStream)

Parameters: This method takes the following arguments as parameter.

  • alt: A description of the alternative service configuration as defined by RFC 7838.
  • originOrStream: Either a URL string specifying the origin (or an Object with an origin property) or the numeric identifier of an active Http2Stream as given by the http2stream.id property.

Return Value: This method does not return any value.

How to generate private key and public certificate



Private key

Step – 1: Open notepad and copy and paste the following key

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

Step – 2: Save as private-key.pem

Public certificate

Step – 1: Open notepad and copy and paste the following key

-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

Step – 2: Save as public-cert.pem

Example 1: Filename: index.js

Javascript




// Node.js program to demonstrate the
// serverhttp2session.altsvc() method
const http2 = require('http2');
const fs = require('fs');
 
// Private key and public certificate for access
const options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem'),
};
 
// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options);
 
server.on('session', (session) => {
  // Set altsvc for origin https://example.org:80
  session.altsvc('h2=":8000"', 'http://localhost:8000');
  console.log("ALTSVC frame is submitted")
});
 
 
server.on('stream', (stream, requestHeaders) => {
 
  // setting response header to client
  // by using respond() method
  stream.respond({ ':status': 200, 'content-type': 'text/plain' });
  stream.write('hello ');
 
   // checking if header is sent or not
   // by using pushAllowed method
   const status = stream.pushAllowed;
 
   if(status)
      stream.end("push stream is accepted");
   else
      stream.end("push stream is not accepted");
 
  // stopping the server by
  // using the close() method
  server.close(()=>{
    console.log("server destroyed");
  })
});
server.listen(8000);
 
 
// creating and initializing client
// by using tls.connect() method
const client = http2.connect(
        'http://localhost:8000');
 
const req = client.request({
    ':method': 'GET',
    ':path': '/'
});
 
req.on('response', (responseHeaders) => {
   
  console.log("status : "
    + responseHeaders[":status"]);
});
 
req.on('data', (data) => {
 
  console.log('Received: %s ',
          data.toString().replace(/(\n)/gm,""));
});
 
req.on('end', () => {
  client.close(()=>{
    console.log("client destroyed");
  })
   
});

Output:

ALTSVC frame is submitted
status : 200
Received: hello
Received: push stream is accepted
client destroyed
server destroyed

Run the index.js file using the following command:

node index.js

Example 2: Filename: index.js

Javascript




// Node.js program to demonstrate the
// serverhttp2session.altsvc() API
const http2 = require('http2');
const fs = require('fs');
 
// private key and public certificate for access
const options = {
  key: fs.readFileSync('private-key.pem'),
  cert: fs.readFileSync('public-cert.pem'),
};
 
// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options);
 
server.on('stream', (stream, requestHeaders) => {
 
  // Setting response header to client
  // by using respond() method
  stream.respond({
    ':status': 200,
    'content-type': 'text/plain'
  });
 
  stream.write('hello ');
 
  const session = stream.session;
 
  // Set altsvc for origin
  session.altsvc('h2=":8000"',
 
  stream.end("ALTSVC frame is submitted")
 
  // Stopping the server by
  // using the close() method
  server.close(()=>{
    console.log("server destroyed");
  })
});
server.listen(8000);
 
 
// Creating and initializing client
// by using tls.connect() method
const client = http2.connect(
        'http://localhost:8000');
 
const req = client.request({
  ':method': 'GET',
  ':path': '/'
});
 
req.on('response', (responseHeaders) => {
   
  console.log("status : "
    + responseHeaders[":status"]);
});
 
req.on('data', (data) => {
 
  console.log('Received: %s ',
          data.toString().replace(/(\n)/gm,""));
});
 
req.on('end', () => {
  client.close(()=>{
    console.log("client destroyed");
  })
   
});

Output:

status : 200
Received: hello
Received: ALTSVC frame is submitted
client destroyed
server destroyed

Run the index.js file using the following command:

node index.js

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http2.html#http2_serverhttp2session_altsvc_alt_originorstream




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