Node.js http2stream.priority() Method

The http2stream.priority() is an inbuilt application programming interface of class Http2Stream within http2 module which is used to update the priority for this Http2Stream instance.

Syntax:

const http2stream.priority(options)

Parameters: This method accepts the following options parameter:

• exclusive: When it is true, the parent identifies a parent Stream and this stream is made the sole direct dependency of the parent, with all other existing dependents made a dependent of this stream otherwise false.
• parent: It is the numeric identifier of a stream.
• weight: It is the relative dependency of a stream in relation to other streams with the same parent.
• silent: When it is true, it changes the priority locally without sending a PRIORITY frame to the connected peer.

Return Value: This method does not return anything.

How to generate the private key and public certificate?

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

   -----BEGIN RSA PRIVATE KEY-----
   MIICXQIBAAKBgQC38R9wXcUbhOd44FavgmE5R3K4JeYOHLnI7dUq1B8/Gv7l3SOg
   JKef/m9gM1KvUx951mapXGtcWgwB08J3vUE2YOZ4tWJArrVZES0BI/RmFAyhQFP5
   HcWl3LSM9LRihP98F33oIkKaCxA5LxOrkgpV4HrUzIKTABDYah7RPex1WQIDAQAB
   AoGBAIXR71xxa9gUfc5L7+TqBs+EMmrUb6Vusp8CoGXzQvRHMJCMrMFySV0131Nu
   o0YYRDsAh1nJefYLMNcXd1BjqI+qY8IeRsxaY+9CB2KKGVVDO2uLdurdC2ZdlWXT
   Vwr3dDoyR0trnXJMmH2ijTeO6bush8HuXxvxJBjvEllM5QYxAkEA3jwny9JP+RFu
   0rkqPBe/wi5pXpPl7PUtdNAGrh6S5958wUoR4f9bvwmTBv1nQzExKWu4EIp+7vjJ
   fBeRZhnBvQJBANPjjge8418PS9zAFyKlITq6cxmM4gOWeveQZwXVNvav0NH+OKdQ
   sZnnDiG26JWmnD/B8Audu97LcxjxcWI8Jc0CQEYA5PhLU229lA9EzI0JXhoozIBC
   TlcKFDuLm88VSmlHqDyqvF9YNOpEdc/p2rFLuZS2ndB4D+vu6mjwc5iZ3HECQCxy
   GBHRclQ3Ti9w76lpv+2kvI4IekRMZWDWnnWfwta+DGxwCgw2pfpleBZkWqdBepb5
   JFQbcxQJ0wvRYXo8qaUCQQCgTvWswBj6OTP7LTvBlU1teAN2Lnrk/N5AYHZIXW6m
   nUG9lYvH7DztWDTioXMrruPF7bdXfZOVJD8t0I4OUzvC
   -----END RSA PRIVATE KEY-----
   

   Now save the file as private-key.pem

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

   -----BEGIN CERTIFICATE-----
   MIICfzCCAegCCQDxxeXw914Y2DANBgkqhkiG9w0BAQsFADCBgzELMAkGA1UEBhMC
   SU4xEzARBgNVBAgMCldlc3RiZW5nYWwxEDAOBgNVBAcMB0tvbGthdGExFDASBgNV
   BAoMC1BhbmNvLCBJbmMuMRUwEwYDVQQDDAxSb2hpdCBQcmFzYWQxIDAeBgkqhkiG
   9w0BCQEWEXJvZm9mb2ZAZ21haWwuY29tMB4XDTIwMDkwOTA1NTExN1oXDTIwMTAw
   OTA1NTExN1owgYMxCzAJBgNVBAYTAklOMRMwEQYDVQQIDApXZXN0YmVuZ2FsMRAw
   DgYDVQQHDAdLb2xrYXRhMRQwEgYDVQQKDAtQYW5jbywgSW5jLjEVMBMGA1UEAwwM
   Um9oaXQgUHJhc2FkMSAwHgYJKoZIhvcNAQkBFhFyb2ZvZm9mQGdtYWlsLmNvbTCB
   nzANBgkqhkiG9w0BAQEFAAOBjQAwgYkCgYEAt/EfcF3FG4TneOBWr4JhOUdyuCXm
   Dhy5yO3VKtQfPxr+5d0joCSnn/5vYDNSr1MfedZmqVxrXFoMAdPCd71BNmDmeLVi
   QK61WREtASP0ZhQMoUBT+R3Fpdy0jPS0YoT/fBd96CJCmgsQOS8Tq5IKVeB61MyC
   kwAQ2Goe0T3sdVkCAwEAATANBgkqhkiG9w0BAQsFAAOBgQATe6ixdAjoV7BSHgRX
   bXM2+IZLq8kq3s7ck0EZrRVhsivutcaZwDXRCCinB+OlPedbzXwNZGvVX0nwPYHG
   BfiXwdiuZeVJ88ni6Fm6RhoPtu2QF1UExfBvSXuMBgR+evp+e3QadNpGx6Ppl1aC
   hWF6W2H9+MAlU7yvtmCQQuZmfQ==
   -----END CERTIFICATE-----
   

   Now save the file as public-cert.pem

Example 1: Filename: index.js

// Node.js program to demonstrate the
// Http2Stream.priority(options) 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'),
};

// Some element for priority
const options1 = {
  exclusive:  true,
  parent: 8000,
  weight: 24,
  silent:  true,
};

// 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 ');

   // Checking if stream has been assigned
   // by using priority(options) method
   const status = stream.priority(options1);

   stream.end("priority has been set");

   // 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");
  })
});

Run the index.js file using the following command:

node index.js

Output:

status : 200
Received: hello
Received: priority has been set
client destroyed
server destroyed

Example 2: Filename: index.js

// Node.js program to demonstrate the
// Http2Stream.priority() 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'),
};

// Some element for priority
const options1 = {
  exclusive:  true,
  parent: 8000,
  weight: 24,
  silent:  true,
};

// Creating and initializing server
// by using http2.createServer() method
const server = http2.createServer(options);

server.on('stream', (stream, requestHeaders) => {

   // Checking if stream has been assigned
   // by using priority(options) method
   const status = stream.priority(options1);

   stream.end("priority has been set");

   // 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('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:

Received: stream has been assigned
client destroyed
server destroyed

Reference: https://nodejs.org/dist/latest-v12.x/docs/api/http2.html#http2_http2stream_priority_options