Decentralized Instant Messaging Protocol (Java)

Dependencies

• Latest Versions

Name	Version	Description
Cryptography		Crypto Keys
Ming Ke Ming (名可名)		Decentralized User Identity Authentication
Dao Ke Dao (道可道)		Universal Message Module

• build.gradle

allprojects {
    repositories {
        mavenLocal()
        mavenCentral()
        google()
    }
}

dependencies {

    // https://central.sonatype.com/artifact/chat.dim/DIMP
    implementation group: 'chat.dim', name: 'DIMP', version: '2.0.0'

}

• pom.xml

<dependencies>

    <!-- https://mvnrepository.com/artifact/chat.dim/DIMP -->
    <dependency>
        <groupId>chat.dim</groupId>
        <artifactId>DIMP</artifactId>
        <version>2.0.0</version>
        <type>pom</type>
    </dependency>

</dependencies>

Examples

Extends Command

• Handshake Command Protocol 0. (C-S) handshake start
  1. (S-C) handshake again with new session
  2. (C-S) handshake restart with new session
  3. (S-C) handshake success

public enum HandshakeState {
    START,    // C -> S, without session key(or session expired)
    AGAIN,    // S -> C, with new session key
    RESTART,  // C -> S, with new session key
    SUCCESS,  // S -> C, handshake accepted
}

/**
 *  Handshake command message
 *
 *  <blockquote><pre>
 *  data format: {
 *      type : 0x88,
 *      sn   : 123,
 *
 *      command : "handshake",    // command name
 *      title   : "Hello world!", // "DIM?", "DIM!"
 *      session : "{SESSION_KEY}" // session key
 *  }
 *  </pre></blockquote>
 */
public class HandshakeCommand extends BaseCommand {

    public final static String HANDSHAKE = "handshake";

    public HandshakeCommand(Map<String, Object> content) {
        super(content);
    }

    public HandshakeCommand(String text, String session) {
        super(HANDSHAKE);
        // text message
        assert text != null : "new handshake command error";
        put("title", text);
        // session key
        if (session != null) {
            put("session", session);
        }
    }

    public String getTitle() {
        return getString("title", null);
    }

    public String getSessionKey() {
        return getString("session", null);
    }

    public HandshakeState getState() {
        return checkState(getTitle(), getSessionKey());
    }

    private static HandshakeState checkState(String text, String session) {
        assert text != null : "handshake title should not be empty";
        if (text.equals("DIM!")/* || text.equals("OK!")*/) {
            return HandshakeState.SUCCESS;
        } else if (text.equals("DIM?")) {
            return HandshakeState.AGAIN;
        } else if (session == null) {
            return HandshakeState.START;
        } else {
            return HandshakeState.RESTART;
        }
    }

    //
    //  Factories
    //

    public static HandshakeCommand start() {
        return new HandshakeCommand("Hello world!", null);
    }

    public static HandshakeCommand restart(String sessionKey) {
        return new HandshakeCommand("Hello world!", sessionKey);
    }

    public static HandshakeCommand again(String sessionKey) {
        return new HandshakeCommand("DIM?", sessionKey);
    }

    public static HandshakeCommand success(String sessionKey) {
        return new HandshakeCommand("DIM!", sessionKey);
    }
}

Extends Content

/**
 *  Application Customized message: {
 *      'type' : i2s(0xA0),
 *      'sn'   : 123,
 *
 *      'app'   : "{APP_ID}",  // application (e.g.: "chat.dim.sechat")
 *      'extra' : info         // others
 *  }
 */
public class ApplicationContent extends BaseContent implements AppContent {

    public ApplicationContent(Map<String, Object> content) {
        super(content);
    }

    public ApplicationContent(String app) {
        super(ContentType.APPLICATION);
        put("app", app);
    }

    @Override
    public String getApplication() {
        return getString("app", "");
    }

}

Extends ID Address

• Examples in Plugins

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