gunzip_http_response.js

// Example usage: node gunzip_http_response.js http://www.httpbin.org/gzip
const http = require('http');
const zlib = require('zlib');

const url = process.argv[2];

console.log(`Requesting ${url}...`);

const req = http.request(url);

req.on('response', function(incomingMessage) {
    console.log(`STATUS: ${incomingMessage.statusCode}`);
    console.log(`HEADERS: ${JSON.stringify(incomingMessage.headers)}`);

    let responseBody = Buffer.alloc(0);

    // If you set the encoding, you'll get string chunks instead of buffer chunks
    // incomingMessage.setEncoding('utf8');
    incomingMessage.on('data', function (chunk) {
        if (typeof(chunk) === 'string') {
            console.error("WARNING: Processing a string instead of a buffer. YUCK!");
        }

        responseBody = Buffer.concat([responseBody, chunk]);
    });

    incomingMessage.on('end', function () {
        console.log();
        const destination = process.stdout;

        if (incomingMessage.headers['content-encoding'] === 'gzip') {
            console.log('gunzipping response...');
            console.log();

            const gunzip = zlib.createGunzip();
            gunzip.pipe(destination);
            gunzip.write(responseBody);
        }
        else {
            console.log();
            destination.write(responseBody);
        }
    });
});

req.on('error', (e) => {
    console.error(`problem with request: ${e.message}`);
  });

req.end();