Kavoshgar is a Simple Service Discovery Protocol (SSDP) for JVM written in Kotlin.

As a demo, I also developed a LAN messenger on top of it for both Android and Desktop using KMP.

SSDP

According to Wikipedia:

"The Simple Service Discovery Protocol (SSDP) is a network protocol based on the Internet protocol suite for advertisement and discovery of network services and presence information. It accomplishes this without assistance of server-based configuration mechanisms, such as Dynamic Host Configuration Protocol (DHCP) or Domain Name System (DNS), and without special static configuration of a network host."

In simple words, giving a network with a couple of nodes, some of them can decide to become a server and, other nodes (i.e., clients) will be notified about the presence of servers.

Usage

Only the network nodes you want to be a server should start advertising presence information:

val server = KavoshgarServer(name = "Test Server")
server.advertisePresence()

All other network nodes are clients by default and should start discovering available servers:

KavoshgarClient()
    .startServerDiscovery()
    .collect { server ->
        println("Server discovered: ${server.addressName}")
    }

▶ Demo

This repository contains a demo application built on top of Kavoshgar to showcase its features and usage. It is a LAN messenger that you can chat with anybody on the same network. The application supports both Android and Desktop platforms using Compose Multiplatform:

• Android Demo
• Desktop Demo

⚙ Technologies

The project is based on socket programming.

Other technologies used in demo applications:

• Kotlin Coroutines
• Kotlin Multiplatform
• Compose Multiplatform
• Material 3
• AndroidX Lifecycle
• Version Catalog

💡 Inspiration

This was the final project for the Internet Engineering course during my B.Sc. in Computer Engineering. I was curious about how in LAN multiplayer video games (Counter-Strike, for example), players join a lobby and start playing the game without knowing each other's network address. And it took me to the SSDP.

🤝 Contribution

Feel free to create pull requests.

🙏 Acknowledgment

Thanks to Dr. Nastooh Taheri Javan for his guidance toward the project.

License

Copyright 2023 Ali Bagherifam

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.