MMO Server implementation (work in progress)

Currently working on:

• Deploying to azure with Terraform

Build locally with docker

you may need to add some entries to your HOSTS file to point services from docker-compose.yml to application.yml The relevant entries are:

127.0.0.1 redis
127.0.0.1 mongo-service
127.0.0.1 kafka-broker

In windows, the hosts file can be found in: C:\Windows\System32\drivers\etc\hosts.file

In Mac, you need to edit /etc/hosts and add the same entries

Documentation within blog:

Each of the posts contains a video overview.

Stats system and level ups

• handling level ups: https://unreal-mmo-dev.com/2024/08/02/devlog-62-how-i-added-xp-and-level-ups-in-our-mmo-rpg-style-game-with-ue-and-java/
• base stats system, used with items: https://unreal-mmo-dev.com/2023/07/19/45-how-to-handle-rpg-stats-system-and-equipping-items-in-java/

UDP communication, player & motion sync

• integration: https://unreal-mmo-dev.com/2024/06/27/devlog-60-how-to-handle-mmo-style-motion-with-ue-and-custom-server-over-udp/
• UDP with Object deliver in UE: https://unreal-mmo-dev.com/2024/06/20/devlog-59-udp-with-free-object-deliverer-plugin-in-ue/

Websocket communication, player and mob motion sync

• Part 1: Overview of architecture: https://unreal-mmo-dev.com/2023/05/10/39-how-to-synchronize-motion-effectively-with-ue-and-custom-server/
• Part 2: Dive into the backend flow https://unreal-mmo-dev.com/2023/05/11/40-how-to-make-a-good-backend-for-your-mmo-game-and-unreal-engine/
• Part 3: Unreal Engine integration sample: https://unreal-mmo-dev.com/2023/05/14/41-how-to-turn-your-unreal-engine-to-mmo-using-custom-server-and-websockets/
• Part 4: How to smooth player/mob motion https://unreal-mmo-dev.com/2023/05/14/42-how-to-make-smooth-motion-for-your-actors-in-ue/
• Part 5: How to spawn mobs and sync them to this server: https://unreal-mmo-dev.com/2023/05/15/43-how-to-spawn-and-control-mobs-using-unreal-engine-for-mmo/

Character creation examples:

• Part 1: overview using N-Hance Assets: https://unreal-mmo-dev.com/2022/08/10/20-unreal-engine-mmo-style-character-creation-with-n-hance-assets/
• Part 2: Complex nested options: https://unreal-mmo-dev.com/2022/08/17/21-unreal-engine-character-creation-part-2-complex-nested-options/
• Part 3: Apply nested options to meshes: https://unreal-mmo-dev.com/2022/08/27/22-unreal-engine-character-creation-part-3-apply-options-to-mesh-n-hance/
• Part 4: Connecting implementation with the server: https://unreal-mmo-dev.com/2022/09/29/23-unreal-engine-character-creation-part-4-connect-to-custom-server/
• Part 5: Select character screen connected with server: https://unreal-mmo-dev.com/2022/10/08/24-unreal-engine-character-creation-part-5-select-character-with-server/

Logging into the game:

• Part 1: https://unreal-mmo-dev.com/2022/10/19/24-unreal-engine-logging-into-a-custom-server/
• Part 2: https://unreal-mmo-dev.com/2022/10/26/26-unreal-engine-synchronize-motion-with-a-custom-server/
• part 3: https://unreal-mmo-dev.com/2022/11/14/27-unreal-engine-display-nearby-players-with-custom-server/
• part 4: https://unreal-mmo-dev.com/2022/11/24/28-unreal-engine-synchronize-nearby-player-appearance/

Inventory Implementation

• Base implementation: https://unreal-mmo-dev.com/2022/05/11/creating-mmo-rpg-style-inventory-system-with-java-and-mongodb/
• Base integration with UE: https://unreal-mmo-dev.com/2022/05/27/14-mmo-rpg-inventory-in-unreal-engine-server/
• Customise inventory: https://unreal-mmo-dev.com/2022/06/12/16-ue-customized-mmo-rpg-inventory/
• Equipping items example: https://unreal-mmo-dev.com/2022/07/02/17-java-mmo-rpg-inventory-implementation-equipping-items/
• Equipping items continued: https://unreal-mmo-dev.com/2022/07/24/19-unreal-engine-equip-inventory-items-with-custom-server/

Base components, JWT no longer in use, in favor of using Cognito or alternatives

• Configuring MongoDB & creation of characters for account: https://unreal-mmo-dev.com/2021/05/08/7-java-micronaut-with-mongodb-character-controller/

• Setting up Micronaut, jooq, flyway (deprecated with v0.7): https://unreal-mmo-dev.com/2021/04/18/4-java-micronaut-dockered-postgres/

• Setting up JWT Authentication (deprecated): https://unreal-mmo-dev.com/2021/04/26/5-java-micronaut-jwt-authentication/

• Encode password for user, integrate with JWT: https://unreal-mmo-dev.com/2021/05/04/6-java-secure-encode-user-credential/

This project branches from the Micronaut template found here: https://github.com/yazoo321/micronaut_template

To see where components are configured, see mini tutorial on youtube: https://www.youtube.com/watch?v=PF_Bg6CgMts&t=16s

JWT Authentication described here on YouTube tutorial here: https://www.youtube.com/watch?v=acAFcDWuxhI&t=8s

Dependencies

In this project we rely on Docker, you can download it here: https://docs.docker.com/desktop/windows/install/ Docker will be used to spin up the dependencies, including any DBs (postgres, mongodb) and now Kafka + Zookeeper.

Kafka

More in-depth Kafka instructions here: https://unreal-mmo-dev.com/2023/04/17/37-how-to-connect-your-java-micronaut-springboot-with-kafka-sasl/

There was a very useful video covering some details that can be found here: https://www.youtube.com/watch?v=bj5SKXanaAI

Kafka is spun up using 'docker-compose' so check the relevant entries there. the './configs' directory contains the necessary configs for SASL enabled Kafka Do note that you will need to change these for production use.

Some useful kafka CLI commands:

// create topic:
kafka-topics --create --bootstrap-server kafka1:9093 --replication-factor 1 --partitions 1 --topic test
--command-config /etc/kafka/configs/config.properties

// producer example:
kafka-console-producer --broker-list kafka1:9093 --topic test --producer.config /etc/kafka/configs/config.properties

// consumer example:
kafka-console-consumer --bootstrap-server kafka1:9093 --topic test --from-beginning --partition 0
--consumer.config /etc/kafka/configs/config.properties

Micronaut also offers some useful documentation: https://guides.micronaut.io/latest/micronaut-kafka-maven-java.html

Micronaut 2.4.1 Documentation

• User Guide
• API Reference
• Configuration Reference

• Micronaut Guides

Feature http-client documentation

• Micronaut HTTP Client documentation

Getting started

In order to build the project run: ./gradlew build

In order to remove the docker container and its database, run docker rm -f -v <container_name>

This project is a base template for getting started with micronaut + postgres + jooq + flyway + lombok.

It contains a very simple migration file (resources/db/postgres/V1__create_user_table.sql) to create a base users table and an entry with a user. Modify this based on your requirements.

Sample request to socket

The inventory sample requests can be found in: resources/inventory/inventorySampleRequests

Motion sample requests can be found in: resources/motion/updateMotionRequest