package com.google.serviceacc;
import java.io.FileInputStream;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.KeyStore;
import java.security.KeyStoreException;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.Signature;
import java.security.SignatureException;
import java.security.UnrecoverableKeyException;
import java.security.cert.CertificateException;
import org.apache.commons.codec.binary.Base64;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpException;
import org.apache.commons.httpclient.methods.PostMethod;
import org.json.JSONException;
import org.json.JSONObject;
public class GoogleServiceAccount<E> {
static String keyAlias = "privatekey";
public static byte[] signData(byte[] data, PrivateKey privateKey) throws InvalidKeyException, SignatureException, NoSuchAlgorithmException
{
Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign(privateKey);
signature.update(data);
return signature.sign();
}
/*public static String encodeBase64(byte[] rawData)
{
byte[] data = Base64.encodeBase64(rawData);
return data.toString();
}*/
private static PrivateKey getPrivateKey(String keyFile, String password)
throws KeyStoreException, IOException, NoSuchAlgorithmException, CertificateException, UnrecoverableKeyException
{
KeyStore keystore = KeyStore.getInstance("PKCS12");
keystore.load(new FileInputStream(keyFile), password.toCharArray());
PrivateKey privateKey = (PrivateKey) keystore.getKey(keyAlias, password.toCharArray());
return privateKey;
}
public static void main(String[] args) throws InvalidKeyException, SignatureException, NoSuchAlgorithmException, UnrecoverableKeyException, KeyStoreException, CertificateException, IOException {
String keystoreLoc = "C:/Users/xyz/Downloads/b5b400df17628d8.p12";
String password = "notasecret";
String jwtStr=null;
String jwtClaimStr=null;
PrivateKey privateKey=null;
JSONObject jwtHeader=new JSONObject();
try {
jwtHeader.put("alg","RS256");
jwtHeader.put("typ","JWT");
jwtStr= jwtHeader.toString();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
byte[] encodedHeader = Base64.encodeBase64(jwtStr.getBytes("UTF-8"));
System.out.println("Original HEaderString: " + jwtStr );
System.out.println("Base64 Encoded HeaderString : " + new String(encodedHeader));
JSONObject jwtClaimSet= new JSONObject();
try {
jwtClaimSet.put("iss", "client_id_email@developer.gserviceaccount.com");
jwtClaimSet.put("scope", "https://www.googleapis.com/auth/devstorage.readonly");
jwtClaimSet.put("aud", "https://accounts.google.com/o/oauth2/token");
jwtClaimSet.put("exp", "1328554385");
jwtClaimSet.put("iat", "1328550785");
jwtClaimStr=jwtClaimSet.toString();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
byte[] encodedClaimSet=Base64.encodeBase64(jwtClaimStr.getBytes("UTF-8"));
System.out.println("Original ClaimSet String:"+jwtClaimStr);
System.out.println("Base64 Encoded ClaimSet:"+ new String(encodedClaimSet) );
StringBuffer token = new StringBuffer();
token.append(Base64.encodeBase64(jwtStr.getBytes("UTF-8")));
token.append(".");
token.append(Base64.encodeBase64(jwtClaimStr.getBytes("UTF-8")));
privateKey= getPrivateKey(keystoreLoc, password);
byte[] sig = signData(token.toString().getBytes("UTF-8"), privateKey);
byte[] signedPayload =Base64.encodeBase64(sig);
token.append(".");
token.append(signedPayload);
HttpClient client = new HttpClient();
PostMethod method = new PostMethod("https://accounts.google.com/o/oauth2/token");
method.addRequestHeader("Content-Type", "application/x-www-form-urlencoded");
method.addParameter("grant_type","urn:ietf:params:oauth:grant-type:jwt-bearer");
System.out.println("printing Token.toString():"+token.toString());
method.addParameter("assertion",token.toString());
System.out.println("Printing QuerString:"+method.getQueryString());
System.out.println("Printing request char set:"+method.getRequestCharSet());
try {
int responseCode=client.executeMethod(method);
System.out.println(responseCode);
System.out.println(method.getResponseBodyAsString());
System.out.println(method.getURI());
} catch (HttpException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
If i try to execute the above code i' am getting { "error" : "invalid_grant" } I created a service account and was able to download private key through the above code.But when i try to exute the request to retrieve the accesstoken iam getting invalid grant error Do I need to add something?
