Java GDAX Authenticated REST Request HTTP GET Error 400

Question

I am trying to GET data from GDAX Exchange with an authenticated API request. I'm starting with a simple account balance check.

I've been tweaking my code for about 8 hours and can't seem to get anything other than a 400 response. Can anyone help me understand what I'm doing wrong?

https://docs.gdax.com/#authentication

All REST requests must contain the following headers:

• CB-ACCESS-KEY The api key as a string.
• CB-ACCESS-SIGN The base64-encoded signature (see Signing a Message).
• CB-ACCESS-TIMESTAMP A timestamp for your request.
• CB-ACCESS-PASSPHRASE The passphrase you specified when creating the API key.

All request bodies should have content type application/json and be valid JSON.

~

The CB-ACCESS-SIGN header is generated by creating a sha256 HMAC using the base64-decoded secret key on the prehash string timestamp + method + requestPath + body (where + represents string concatenation) and base64-encode the output. The timestamp value is the same as the CB-ACCESS-TIMESTAMP header.

The body is the request body string or omitted if there is no request body (typically for GET requests).

The method should be UPPER CASE.

~

private static JSONObject getAuthenticatedData() {
    try {

        String accessSign = getAccess();


        URL url = new URL("https://api.gdax.com/accounts");
        HttpURLConnection con = (HttpURLConnection) url.openConnection();
        con.setRequestMethod("GET");
        con.setRequestProperty("Content-Type", "application/json");

        con.setRequestProperty("CB-ACCESS-KEY", "d281dc......");
        con.setRequestProperty("CB-ACCESS-SIGN", accessSign);
        con.setRequestProperty("CB-ACCESS-TIMESTAMP", ""+System.currentTimeMillis() / 1000L);
        con.setRequestProperty("CB-ACCESS-PASSPHRASE", "xxxxx.....");

        con.setConnectTimeout(5000);
        con.setReadTimeout(5000);

        int status = con.getResponseCode();

        BufferedReader in = new BufferedReader(new InputStreamReader(con.getInputStream()));
        String inputLine;
        StringBuffer content = new StringBuffer();
        while ((inputLine = in.readLine()) != null) {
            content.append(inputLine);
        }
        System.out.println(content);
        in.close();

        con.disconnect();

    }catch(Exception e) {
        e.printStackTrace();
    }
    return null;


}

~

public static String getAccess() {

    //Set the Secret
    String secret = "xxxxxxx........";
    //Build the PreHash
    String prehash = Instant.now().toEpochMilli()+"GET"+"/accounts";
    String hash = null;
    try {

        Mac sha256_HMAC = Mac.getInstance("HmacSHA256");
        SecretKeySpec secret_key = new SecretKeySpec(secret.getBytes(), "HmacSHA256");
        sha256_HMAC.init(secret_key);

        hash = Base64.encodeBase64String(sha256_HMAC.doFinal(prehash.getBytes()));
        System.out.println(hash);
       }
       catch (Exception e){
           e.printStackTrace();
       }
    return hash;   
}

Answer 1

You need to add request headers and request properties.

Here is and example of exactly what you are trying to do:

Create Signature

Create Headers

Answer 2

A 400 means that the request was malformed. In other words, the data stream sent by the client to the server didn't follow the rules.

So, something is wrong by your side. In official doc it is mentioned that you should request POST method but you have have request GET method.

 URL url = new URL("https://api.gdax.com/accounts");
 HttpURLConnection con = (HttpURLConnection) url.openConnection();
 con.setRequestMethod("POST");

Hope, this may help!