Setting up a checksum on user and team instances to lower connection delay

Pierre-yves Baloche

2015-03-06 f6cbed8bf3fd630f1d02832240e93fa89dd118e3

Setting up a checksum on user and team instances to lower connection delay

 src/main/java/com/gitblit/auth/AuthenticationProvider.java

@@ -15,7 +15,13 @@
 */
package com.gitblit.auth;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@@ -77,25 +83,70 @@
        }
    }

    /**
     * Utility method to calculate the checksum of an object.
     * @param sourceObject The object from which to establish the checksum.
     * @return The checksum
     * @throws IOException
     * @throws NoSuchAlgorithmException
     */
    private BigInteger checksum(Object sourceObject) throws IOException, NoSuchAlgorithmException {

        if (sourceObject == null) {
          return BigInteger.ZERO;   
        }

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ObjectOutputStream oos = new ObjectOutputStream(baos);
        oos.writeObject(sourceObject);
        oos.close();

        MessageDigest m = MessageDigest.getInstance("SHA1");
        m.update(baos.toByteArray());

        return new BigInteger(1, m.digest());
    }
	
    protected void updateUser(UserModel userModel) {
        // TODO implement user model change detection
        // account for new user and revised user

        // username
        // displayname
        // email address
        // cookie

        userManager.updateUserModel(userModel);
        final UserModel userLocalDB = userManager.getUserModel(userModel.getName());
        try {
            // Establish the checksum of the current version of the user
            final BigInteger userCurrentCheck = checksum(userModel);
            // Establish the checksum of the stored version of the user
            final BigInteger userLocalDBcheck = checksum(userLocalDB);
            // Compare the checksums
            if (!userCurrentCheck.equals(userLocalDBcheck))
            {
                // If mismatch, save the new instance.
                userManager.updateUserModel(userModel);
            }
        } catch (NoSuchAlgorithmException | IOException e) {
            // Trace any potential error.
            if (logger.isErrorEnabled()) {
                logger.error(e.getMessage());
            }
        }
    }

    protected void updateTeam(TeamModel teamModel) {
        // TODO implement team model change detection
        // account for new team and revised team

        // memberships

        userManager.updateTeamModel(teamModel);
        final TeamModel teamLocalDB = userManager.getTeamModel(teamModel.name);
        try {
            // Establish the checksum of the current version of the team
            final BigInteger teamCurrentCheck = checksum(teamModel);
            // Establish the checksum of the stored version of the team
            final BigInteger teamLocalDBcheck = checksum(teamLocalDB);
            // Compare the checksums
            if (!teamCurrentCheck.equals(teamLocalDBcheck))
            {
                // If mismatch, save the new instance.
                userManager.updateTeamModel(teamModel);
            }
        } catch (NoSuchAlgorithmException | IOException e) {
            // Trace any potential error.
            if (logger.isErrorEnabled()) {
                logger.error(e.getMessage());
            }
        }
    }

    public abstract void setup();