Amazon AWIS request works with php but not with node.js code

I tried to make requests to Amazon AWIS, but I always get an error.

The official documentation is available here:

http://ift.tt/1qzyAk6

Making Requests > Calculating Signatures

Here is an official php file to make a request, and it worked:

http://ift.tt/1wFtqS8

I wrote the following code in node.js but it didn't work:

    var key = "foo";
    var host = "awis.amazonaws.com";
    var query =
        "Action=UrlInfo" +
        "&AWSAccessKeyId=bar" +
        "&Count=10" + 
        "&ResponseGroup=Rank" +
        "&SignatureMethod=HmacSHA256" +
        "&SignatureVersion=2" +
        "&Start=1" +
        "&Timestamp=2015-03-01T21%3A05%3A00.005Z" +
        "&Url=stackoverflow.com";

    var stringToSign = 
        "GET\n" + 
        host + "\n" + 
        "/\n" + 
        query;

    log("stringToSign: " + stringToSign);


    var signature = crypto.createHmac("sha256", key).update(stringToSign).digest('hex');

     signature = new Buffer(signature).toString("base64");

    console.log("signature:     " + signature);


    signature = encodeURIComponent(signature).replace(/!/g, '%21').replace(/'/g, '%27').replace(/\(/g, '%28').replace(/\)/g, '%29').replace(/\*/g, '%2A');

    console.log("enc signature: " + signature);

    query += "&Signature=" + signature;

    log("\n\nfinal query:\n" + query);

    request.get({
        url: "http://" + host + "/?" + query,
    }, function(err, response, body) {
        res.send(body);
    });

Could somebody go through the PHP code and my code and check what could be different?

EDIT 1: I found out that the hmac function from php takes a fourth parameter:

hash_hmac('sha256', $sign, $this->secretAccessKey, true) // <- true param

which returns binary data instead of hex data.

I accordingly change my code from this to the other two following examples:

var signature = crypto.createHmac("sha256", key).update(stringToSign).digest("hex");         
signature = signature.toString("base64");

Neither this

var signature = crypto.createHmac("sha256", key).update(stringToSign).digest("binary"); // <- notice "binary"   
console.log(signature); // this returns some strange symbols in cmd, the same as in the php script, so this seems normal
signature = signature.toString("base64");

nor this

var signature = crypto.createHmac("sha256", key).update(stringToSign).digest("binary"); // <- notice "binary"   

signature = (new Buffer(hmac, "binary")).toString("base64");

worked.