oauth2 token refresher

gistfile1.java

/*

# random client_id and random client_secret
curl --form client_id='3MVG9Nc1qcT7BbZ1AmkC7gLt_RtFNrY9XCsATBeio3ijPozoP.4qTcKKDGOT5V2V78I.4Ne1RXRTEJjqoZzNC' \
     --form client_secret='6092197970455970980' \
     --form grant_type=password \
     --form username='[email protected]'\
     --form password='password' \
      https://site.com/services/oauth2/token
      
# save results to test.json

curl https://cs24.salesforce.com/services/apexrest/Fidelity \
     -H 'Authorization: Bearer 00D19000000EFgv!AQ4AQASefbMqsyupDpqCmktdDF5M1x_b2Sf4aQHznBcCP85d2D5c_0kxAifuQQppw4ozgleScpH2pCFqr7P.t4QCmblIEsSi' \
     -H "Content-Type: application/json" -d "@test.json"
     
     
Note. It requires a plain text files with the following lines:
edpoint url
client_id
client secred
grant type
username
password


Originally implemented for Salesforce.com inside Talend ESB.

*/



package routines;

package routines;

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.net.ssl.HttpsURLConnection;

public class OAuthRefresher {

		
	private final static String USER_AGENT = "Mozilla/5.0";

	static String url = "";
	static String client_id = "";
	static String client_secret = "";
	static String grant_type = "";
	static String username="";
	static String password="";
	
	public static String instance_url="";
	public static String token="";
   
    public static String[] refresh(String filename) throws Exception {
    	
    	// reset old variables
    	token = "";
    	instance_url = "";
    	
    	readConf(filename);
    	
		HttpsURLConnection con = getConnection();
		doCall(con);
		String response = handleResponse(con);
		
		dirtyParseJSON(response);
		
		String ret[] = {token , instance_url};
		return ret;
    }
    
    private static void readConf(String filename) {
    	BufferedReader br = null;
    	String line = "";
    	try {
    		List<String> fields = new ArrayList<String>();
    		br = new BufferedReader(new FileReader(filename));
    		while ((line = br.readLine()) != null) {
     
    			fields.add(line);
     
    		}
    		url = fields.get(0);
    		client_id = fields.get(1);
    		client_secret = fields.get(2);
    		grant_type = fields.get(3);
    		username = fields.get(4);
    		password = fields.get(5);     
    	} catch (FileNotFoundException e) {
    		e.printStackTrace();
    	} catch (IOException e) {
    		e.printStackTrace();
    	} finally {
    		if (br != null) {
    			try {
    				br.close();
    			} catch (IOException e) {
    				e.printStackTrace();
    			}
    		}
    	}
    }

	private static boolean dirtyParseJSON(String response) {
		// super dirty manual plain json parsing
		Map<String, String> responseMap = new HashMap<String,String>();
		response = response.substring(1, response.length()-2);
		String[] pairs = response.split("\",\"");
		for(String pair : pairs) {
			String[] s = pair.split("\":\"");
			responseMap.put(s[0], s[1]);
		}
		
		if(responseMap.containsKey("instance_url") && responseMap.containsKey("access_token")) {
			instance_url = responseMap.get("instance_url");
			token = responseMap.get("access_token");
			return true;
		} else {
			return false;
		}
	}

	private static String handleResponse(HttpsURLConnection con)
			throws IOException {
		
		String responseString = null;
		int responseCode = con.getResponseCode();
		InputStreamReader inputStream;
		
		System.out.println("\nSending 'POST' request to URL : " + url);
		System.out.println("Response Code : " + responseCode);
		
		if (responseCode != 200) {
			System.out.println("Error code: "+responseCode);
			inputStream = new InputStreamReader(con.getErrorStream());
			responseString = "";
        } else {
        	inputStream = new InputStreamReader(con.getInputStream());
        }
		
		BufferedReader in = new BufferedReader(inputStream);
		String inputLine;
		StringBuffer response = new StringBuffer();
 
		while ((inputLine = in.readLine()) != null) {
			response.append(inputLine);
		}
		in.close();
		
		if(responseString==null) {
			responseString = response.toString();
		} else {
			System.out.println("Error string: "+responseString);
		}
				
		return responseString;
	}

	private static void doCall(HttpsURLConnection con) throws IOException {
		// Send post request
		con.setDoOutput(true);
		DataOutputStream wr = new DataOutputStream(con.getOutputStream());
		
		wr.writeBytes("client_id="+ client_id+'&');
		wr.writeBytes("client_secret="+ client_secret+'&');
		wr.writeBytes("grant_type="+ grant_type+'&');
		wr.writeBytes("username="+ username+'&');
		wr.writeBytes("password="+ password+'&');
		
		wr.flush();
		wr.close();
	}

	private static HttpsURLConnection getConnection()
			throws MalformedURLException, IOException, ProtocolException {
		URL obj = new URL(url);
		HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
 
		//add reuqest header
		con.setRequestMethod("POST");
		con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded"); 
		con.setRequestProperty("charset", "UTF-8"); 
		con.setRequestProperty("User-Agent", USER_AGENT);
		return con;
	}
}