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Node.js Http2ServerResponse.hasHeader() Method

  • Last Updated : 09 Dec, 2020

The Http2ServerResponse.hasHeader() is an inbuilt application programming interface of the class Http2ServerResponse within the http2 module which is used to check if the header identified by name is currently set in the outgoing headers or not.

Syntax:

response.hasHeader(name)

Parameters: This method accepts the name of the header as the parameter.

Return Value: This method returns true if and only if the header identified by name is currently set in the outgoing headers or not.

How to generate a Private key and Public certificate?



1. Filename: Private key

Open notepad and copy-paste the following key and save the file as private-key.pem

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

2. Filename: Public certificate

Open notepad and copy-paste the following key and save the file as public-cert.pem

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

Example 1: Filename: index.js

Javascript




// Node.js program to demonstrate the
// Http2ServerResponse.hasHeader() 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'),
};
  
// Request and response handler
const http2Handlers = (request, response) => {
  
  // Setting new header
  response.setHeader(
    'Content-Type'
    'hello world; charset=utf-8'
  );
  
  // Checking if the header is present or not
  // by using hasHeader() method
  const value = response.hasHeader('Content-Type')
  
  // Display the header
  if(value) console.log("header is present")
  else console.log("header is not present")
};
  
// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options, http2Handlers);
  
server.on('stream', (stream, requestheader) => {
  stream.write('hello ');
  
  // Getting all information of this http2stream
  // object by using state method
  const status = stream.state;
  
  stream.end("priority weight : " + status.weight);
  
  // 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(
  
const req = client.request({ 
  ':method': 'GET', ':path': '/'});
  
req.on('response', (responsesocket) => {
  console.log("status : " 
  + responsesocket[":status"]);
});
  
req.on('data', (data) => {
  console.log('Received: %s ',
  data.toString().replace(/(\n)/gm,""));
});
  
req.on('end', () => {
  client.close(() => {
    console.log("client destroyed");
  })
});

Run the index.js file using the following command:

node index.js

Output:

header is present
status : 200
Received: hello
Received: priority weight : 16
client destroyed
server destroyed

Example 2: Filename: index.js

Javascript




// Node.js program to demonstrate the
// Http2ServerResponse.hasHeader() 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'),
};
  
// Request and response handler
const http2Handlers = (request, response) => {
  
    // Setting new header
    response.setHeader('Foo', 'bar');
    response.setHeader(
      'Set-Cookie', ['foo=bar', 'bar=baz']);
  
    // Checking if the header is present or not
    // by using hasHeader() method
    const value = response.hasHeader('Content-Type')
  
    // Display the header
    if(value) console.log("header is present")
    else console.log("header is not present")
};
  
// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options, http2Handlers);
  
server.on('stream', (stream, requestHeaders) => {
  
    // Getting all information of this http2stream object
    // by using state method
    const status = stream.state;
  
    stream.end("The sum weight of all Http2Stream : "
    status.sumDependencyWeight);
    
    // 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': '/www.geeksforgeeks.org' });
  
req.on('data', (data) => {
  console.log('Received: %s ',
  data.toString().replace(/(\n)/gm,""));
});
  
req.on('end', () => {
  client.close(() => {
    console.log("client destroyed");
  })
});

Run the index.js file using the following command:

node index.js

Output:

header is not present
Received: The sum weight of all Http2Stream : 0
client destroyed
server destroyed

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http2.html#http2_response_hasheader_name




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