CODEWITHSUNDEEP
javajsoncurl
Mo Lillaney
Mo Lillaney

Reputation: 11

Ameritrade API POST Request JSON Response

I haven't coded in JAVA for years, and am trying to put an algorithm together to automatically make trades based on certain conditions.

I'm hoping to use the Ameritrade API

I've tried sending a cURL message in command prompt and I do indeed get a response back from the server 'Invalid Key'. I'd like to see the 'Invalid Key' response come back in Java as this will prove that I can send POST and receive JSON objects back into Java. From there I will work at authenticating but one step at a time!

Here's the curl message sent in command prompt that works, try it yourself by copying and pasting::

curl -X POST -H "Content-Type: application/x-www-form-urlencoded" -d "grant_type=authorization_code&refresh_token=&access_type=offline&code=&client_id=&redirect_uri=" " https://api.tdameritrade.com/v1/oauth2/token

The first thing I'd like to do is be able to send this curl message in JAVA and receive the JSON response back in JAVA

This is what I have for code so far, but I get a 500 error, which makes me think its something with the way im sending the message to the server? 

public void trytoAuthenticate() {
    HttpURLConnection connection = null;
    //
    //this is the curl message in command prompt you can send to receive JSON response back
    //curl -X POST --header "Content-Type: application/x-www-form-urlencoded" -d 
    //"grant_type=authorization_code&
    //refresh_token=&
    //access_type=offline&
    //code=&
    //client_id=&
    //redirect_uri=" "https://api.tdameritrade.com/v1/oauth2/token"

    try {
        //Create connection
        URL url = new URL("https://api.tdameritrade.com/v1/oauth2/token");
        String urlParameters = "grant_type=" + URLEncoder.encode("authorization_code", "UTF-8") + 
                "&refresh_token=" + URLEncoder.encode("", "UTF-8") + 
                "&access_type=" + URLEncoder.encode("", "UTF-8") + 
                "&code=" + URLEncoder.encode("", "UTF-8") + 
                "&client_id=" + URLEncoder.encode("", "UTF-8") + 
                "&redirect_uri=" + URLEncoder.encode("", "UTF-8");

        connection = (HttpURLConnection) url.openConnection();
        connection.setRequestMethod("POST"); //-X
        connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); //-H
        connection.setRequestProperty("Content-Length", 
                Integer.toString(urlParameters.getBytes().length));
        connection.setRequestProperty("Content-Language", "en-US");  

        connection.setUseCaches(false);
        connection.setDoOutput(true);//connection will be output
        connection.setDoInput(true);//connection will be input

        //Send request
        DataOutputStream wr = new DataOutputStream (connection.getOutputStream());
        wr.writeBytes(urlParameters);
        System.out.println(urlParameters); //added for testing
        wr.close();

        //Get Response  
        DataInputStream is = new DataInputStream (connection.getInputStream());
        BufferedReader rd = new BufferedReader(new InputStreamReader(is));
        rd.readLine();
        //StringBuffer response = new StringBuffer(); // or StringBuffer/StringBuilder if Java version 5+
        //String line;
        //while ((line = rd.readLine()) != null) {
        //  response.append(line);
        //  response.append('\r');
        //}
        rd.close();
        //System.out.println(response.toString());
        //return response.toString();
    } catch (Exception e) {
        e.printStackTrace();
        //return null;
    } finally {
        if (connection != null) {
            connection.disconnect();
        }
    }
}
}

Upvotes: 1

Views: 561

Answers (1)

Andy
Andy

Reputation: 902

A few things:

You need four parameters: grant_type, access_type, redirect_url and code.

  1. You should URLDecode the authorization code you got from the browser login you probably just performed (as per their instructions)

  2. Remove empty parameters, leave only what I mentioned above.

  3. The redirect URL must match EXACTLY the redirect URL you added when you created your APP in the console.

  4. If this is an app (looks like it), you probably have to set the access_type to "offline". Again see their documentation. Depends on your application.

  5. grant_type should be "authorization_code", as that's what you want.

Upvotes: 0

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