example 3

Code-examples/Ex3/instructions.md

+Choosing HTTP/2 and JSON for a Node.js Server
+For this example, let's create a simple Node.js server that uses HTTP/2 and JSON for efficient data transfer.
+
+Step 1: Setting up the project
+Initialize a new Node.js project:
+bash
+Copy code
+npm init -y
+Install the necessary dependencies (assuming you have Node.js 8.4.0 or higher, which includes HTTP/2 support):
+bash
+Copy code
+npm install express
+Step 2: Create a simple HTTP/2 server
+To use HTTP/2 with Node.js, you'll need to create an SSL certificate for local development:
+
+bash
+Copy code
+openssl req -x509 -newkey rsa:2048 -nodes -sha256 -subj '/CN=localhost' -keyout localhost-privkey.pem -out localhost-cert.pem
+Now, let's set up the server:
+
+javascript
+Copy code
+const express = require('express');
+const fs = require('fs');
+const http2 = require('http2');
+const app = express();
+
+app.get('/data', (req, res) => {
+    const data = { message: "Hello, this is a lightweight JSON message!" };
+    res.json(data); // Send JSON response
+});
+
+const options = {
+    key: fs.readFileSync('localhost-privkey.pem'),
+    cert: fs.readFileSync('localhost-cert.pem')
+};
+
+// Create HTTP/2 server
+const server = http2.createSecureServer(options, app);
+
+const PORT = 3000;
+server.listen(PORT, () => {
+    console.log(`HTTP/2 server running on https://localhost:${PORT}`);
+});
+Step 3: Running the server and testing
+Run the server with:
+
+bash
+Copy code
+node yourServerFileName.js
+You can test the server with HTTP/2-supporting tools like curl:
+
+bash
+Copy code
+curl --http2 -k https://localhost:3000/data
+The -k flag is used to avoid SSL certificate validation errors since we're using a self-signed certificate for local testing. The --http2 flag forces curl to use HTTP/2.
+
+Conclusion
+By using HTTP/2 and a compact message format like JSON, we can ensure that the amount of data transmitted over the network is minimized, which contributes to energy savings. It's important to balance the need for efficiency with the requirements of the application and the capabilities of the client and server when choosing a protocol and message format.
\ No newline at end of file

Code-examples/Ex3/localhost-cert.pem

+-----BEGIN CERTIFICATE-----
+MIIDCTCCAfGgAwIBAgIUHegPOn/Xy7KXD/qzNtuxnX2mlSMwDQYJKoZIhvcNAQEL
+BQAwFDESMBAGA1UEAwwJbG9jYWxob3N0MB4XDTIzMTEwNzA5NTAwN1oXDTIzMTIw
+NzA5NTAwN1owFDESMBAGA1UEAwwJbG9jYWxob3N0MIIBIjANBgkqhkiG9w0BAQEF
+AAOCAQ8AMIIBCgKCAQEApXlC4UbDqYsoeZ4/RBrZI2tcDpBXl82WZqSAllb3etBu
+6Y4s3QRDZAyypy3BClHQu9VvyJw1kPYCJRbMa0PWqffXOOgdJtFBcJhMigx4I7Y5
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+xIeO/Gd0cp7nEOWgn7qNGDpP4AULuKe1F7zXOka08YzuzsZ2EZbJC35EddWfnHl1
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+tNfiI81ld35ni4QHWl4LUsdfbCPfxSPK/xUUT3l3zei4QbOQ6JtWLINoiD6+CFOF
+a7BD+MDfZk5GwZywpA==
+-----END CERTIFICATE-----

Code-examples/Ex3/localhost-privkey.pem

+-----BEGIN PRIVATE KEY-----
+MIIEvAIBADANBgkqhkiG9w0BAQEFAASCBKYwggSiAgEAAoIBAQCleULhRsOpiyh5
+nj9EGtkja1wOkFeXzZZmpICWVvd60G7pjizdBENkDLKnLcEKUdC71W/InDWQ9gIl
+FsxrQ9ap99c46B0m0UFwmEyKDHgjtjm1QcOggktfNtbOoC7HhstJNvdbDC2fSPoF
+OYY5acg3yAHXXsGnA+vCGVXPbE4UCkziR1qHyoH3IXxJ4vrV2wYcOsHlIip9haPc
+BqwZ5dF8ObpQTevX5JCdRCt7QRLVx8GfID6GizTqqgZOPqk7Lou7AF80o1ny79mv
+qAcYHlMHc3QGPTGRKbC29QvLrfwAJZ65wY7zqknRi4DSl+s2/yPmj1RVfFsq6Egj
+MQlgxUOlAgMBAAECggEAEwI1kRxocKsIOMRZfzDYXc3A8vlY3pri2qKuFNcjscuM
+2i6Xb8JEHZOp2DOU1+MjJ9iycSikrKTeBTWzwOS3nanXYvWjF6j1LAKK1FbvXCbc
+RTqrRt6A2wy5K15SUWBmLOBwFNj2yrP+6Ke9iA3jTqkesQd1FoMIS7FOXrgR1hJT
+Y5Wt24jslzb/y/wrQMmZuICh+PIulJnlX8v1KJlKdPZwCCqRQa27nxz0mTxiJTNB
++C6NfVF1kbkDxL4gKtkTnKM2mLPz21p2tJSN9tVtth/Vptk3o5V6UuytTZshSo0x
+7oZ+NuLQ6QURHhD57w5vxpyre3Svgph9rbOgRQIfcQKBgQDf0z4JK0cA8A6xJk+i
+upi1Hc/S+HvBRnDqtEhlVzq+4hmMtT7cdcBs+Brwr45m9m2q1U4w2NsDIQqbOF0u
+KswCCmHU5LzcBFGg4Hc6ShMaVy6LMkL512xleBhsXeVKKUJtdQNZnuyevQTUmFGY
+G2ElPnBhlja4b70k/i5Qfnr7yQKBgQC9Qq+zsarcCPDJ+72r03s41JSj5ENFZjHH
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+k1WkWACPQuBZlFfZM2tQKZeaiiVKmMMtmwfwJ1yCKWwgvPu8kg7TfKGoJ6RWmnTd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+-----END PRIVATE KEY-----

Code-examples/Ex3/server.js

+const express = require('express');
+const fs = require('fs');
+const http2 = require('http2');
+const app = express();
+
+app.get('/data', (req, res) => {
+    const data = { message: "Hello, this is a lightweight JSON message!" };
+    res.json(data); // Send JSON response
+});
+
+const options = {
+    key: fs.readFileSync('localhost-privkey.pem'),
+    cert: fs.readFileSync('localhost-cert.pem')
+};
+
+// Create HTTP/2 server
+const server = http2.createSecureServer(options, app);
+
+const PORT = 3000;
+server.listen(PORT, () => {
+    console.log(`HTTP/2 server running on https://localhost:${PORT}`);
+});