org.dasein.cloud.google.GenerateToken.java Source code

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Here is the source code for org.dasein.cloud.google.GenerateToken.java

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/**
 * Copyright (C) 2012-2013 Dell, Inc
 * See annotations for authorship information
 *
 * ====================================================================
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * ====================================================================
 */

package org.dasein.cloud.google;

import org.apache.commons.codec.binary.Base64;
import java.io.*;
import java.security.*;
import java.text.MessageFormat;
import java.util.Enumeration;

public class GenerateToken {

    public static String getToken(String iss, String p12File) {

        String header = "{\"alg\":\"RS256\",\"typ\":\"JWT\"}";
        String claimTemplate = "'{'\"iss\": \"{0}\", \"scope\": \"{1}\", \"aud\": \"{2}\", \"exp\": \"{3}\", \"iat\": \"{4}\"'}'";

        try {
            StringBuffer token = new StringBuffer();

            //Encode the JWT Header and add it to our string to sign
            token.append(Base64.encodeBase64URLSafeString(header.getBytes("UTF-8")));

            //Separate with a period
            token.append(".");

            //Create the JWT Claims Object
            String[] claimArray = new String[5];
            claimArray[0] = iss;
            claimArray[1] = "https://www.googleapis.com/auth/compute";
            claimArray[2] = "https://accounts.google.com/o/oauth2/token";
            claimArray[3] = Long.toString((System.currentTimeMillis() / 1000) + 300);
            claimArray[4] = Long.toString((System.currentTimeMillis() / 1000));
            MessageFormat claims;
            claims = new MessageFormat(claimTemplate);
            String payload = claims.format(claimArray);
            //         System.out.println(claimArray[3]);
            //         System.out.println(claimArray[4]);
            //Add the encoded claims object
            token.append(Base64.encodeBase64URLSafeString(payload.getBytes("UTF-8")));

            char[] password = "notasecret".toCharArray();
            FileInputStream fin = new FileInputStream(new File(p12File));
            KeyStore store = KeyStore.getInstance("PKCS12");
            try {
                store.load(fin, password);
            } finally {
                try {
                    fin.close();
                } catch (IOException e) {
                }
            }
            String alias = "";
            // KeyStore keystore = getKeyStore(password);            
            Enumeration<String> enum1 = store.aliases(); // List the aliases
            while (enum1.hasMoreElements()) {
                String keyStoreAlias = enum1.nextElement().toString();
                if (store.isKeyEntry(keyStoreAlias)) { //Does alias refer to a private key?
                    alias = keyStoreAlias;
                    break;
                }
            }
            PrivateKey privateKey = (PrivateKey) store.getKey(alias, password);

            //Sign the JWT Header + "." + JWT Claims Object
            Signature signature = Signature.getInstance("SHA256withRSA");
            signature.initSign(privateKey);
            signature.update(token.toString().getBytes("UTF-8"));
            String signedPayload = Base64.encodeBase64URLSafeString(signature.sign());

            //Separate with a period
            token.append(".");

            //Add the encoded signature
            token.append(signedPayload);

            //      System.out.println(token.toString());
            return token.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

}