Incorrect Header Check when using zlib in node.js

Question

I am trying to send a simple HTTP POST request, retrieve the response body.Following is my code. I am getting

Error: Incorrect header check

inside the "zlib.gunzip" method. I am new to node.js and I appreciate any help.

;

    fireRequest: function() {

    var rBody = '';
    var resBody = '';
    var contentLength;

    var options = {
        'encoding' : 'utf-8'
    };

    rBody = fSystem.readFileSync('resources/im.json', options);

    console.log('Loaded data from im.json ' + rBody);

    contentLength = Buffer.byteLength(rBody, 'utf-8');

    console.log('Byte length of the request body ' + contentLength);

    var httpOptions = {
        hostname : 'abc.com',
        path : '/path',
        method : 'POST',
        headers : {
            'Authorization' : 'Basic VHJhZasfasNWEWFScsdfsNCdXllcjE6dHJhZGVjYXJk',
            'Content-Type' : 'application/json; charset=UTF=8',
            // 'Accept' : '*/*',
            'Accept-Encoding' : 'gzip,deflate,sdch',
            'Content-Length' : contentLength
        }
    };

    var postRequest = http.request(httpOptions, function(response) {

        var chunks = '';
        console.log('Response received');
        console.log('STATUS: ' + response.statusCode);
        console.log('HEADERS: ' + JSON.stringify(response.headers));
        // response.setEncoding('utf8');
        response.setEncoding(null);
        response.on('data', function(res) {
            chunks += res;
        });

        response.on('end', function() {
            var encoding = response.headers['content-encoding'];
            if (encoding == 'gzip') {

                zlib.gunzip(chunks, function(err, decoded) {

                    if (err)
                        throw err;

                    console.log('Decoded data: ' + decoded);
                });
            }
        });

    });

    postRequest.on('error', function(e) {
        console.log('Error occured' + e);
    });

    postRequest.write(rBody);
    postRequest.end();

}

question from:https://stackoverflow.com/questions/19438884/incorrect-header-check-when-using-zlib-in-node-js

Answer 1

response.on('data', ...) can accept a Buffer, not just plain strings. When concatenating you are converting to string incorrectly, and then later can't gunzip. You have 2 options:

1) Collect all the buffers in an array, and in the end event concatentate them using Buffer.concat(). Then call gunzip on the result.

2) Use .pipe() and pipe the response to a gunzip object, piping the output of that to either a file stream or a string/buffer string if you want the result in memory.

Both options (1) and (2) are discussed here: http://nickfishman.com/post/49533681471/nodejs-http-requests-with-gzip-deflate-compression