Node.js http2.bufferSize Method

The http2.bufferSize is an inbuilt application programming interface of class Http2Stream within http2 module which is used to get the number of characters currently buffered to be written.

Syntax:

const http2stream.bufferSize

Parameters: This method does not accept any parameter.

Return Value: This method returns the number of characters currently buffered to be written.

How to generate the private key and public certificate?

Private key: Open notepad and copy paste the following key:

Now save the file as private-key.pem

Public certificate: Open notepad and copy paste the following key:

Now save the file as public-cert.pem

Example 1: Filename: index.js

JavaScript

// Node.js program to demonstrate the
// Http2Stream.bufferSize 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('stream', (stream, requestHeaders) => {
  stream.respond({ 
    ':status': 200, 
    'content-type': 'text/plain' 
  });

  stream.write('hello ');
  stream.end('world');

  // Getting buffer size
  // by using stream.bufferSize method
  const value = stream.bufferSize;

  console.log("buffer size : " + value);
  
  // Stopping the server
  // by using the close() method
  server.close(() => {
    console.log("server closed");
  })
});

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 closed");
  })
});

Run the index.js file using the following command:

node index.js

Output:

buffer size : 17
status : 200
Received: hello
Received: world
client closed
server closed

Example 2: Filename: index.js

JavaScript

// Node.js program to demonstrate the
// Http2Stream.bufferSize 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('stream', (stream, requestHeaders) => {
  // Getting buffer size
  // by using stream.bufferSize method
  const value = stream.bufferSize;

  stream.end("buffer size : " + value);
  
  // Stopping the server
  // by using the close() method
  server.close(() => {
    console.log("server closed");
  })
});

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('data', (data) => {
  console.log('Received: %s ',
  data.toString().replace(/(\n)/gm, ""));
});

req.on('end', () => {
  client.close(() => {
    console.log("client closed");
  })
});

Run the index.js file using the following command:

node index.js

Output:

Received: buffer size : 0
client closed
server closed

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http2.html#http2_http2stream_buffersize

Node.js http2.bufferSize Method

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