This is a fork of devopvoid's webrtc-java library, a Java wrapper for the WebRTC Native API. You can join the Discord for help with this fork.

This fork

This is jlftt's fork of Kas-tle/webrtc-java, used by the Geyser portal bridge through NetworkCompatible. It fixes memory leaks that grew a busy Velocity proxy's heap by about 100 MB an hour:

• Every received message leaked two Java objects, the RTCDataChannelBuffer handed to the observer and the direct ByteBuffer inside it. OnMessage runs on a native thread that stays attached to the JVM, so the JNI local references it created were never freed. They are now deleted after each message.
• Every closed connection leaked its native PeerConnection: close() cleared the Java handle without releasing the reference it owned. It now releases it. Because the connection is really freed now, every other call takes its own reference to it first, under the same monitor close() empties the handle under, so a call racing with close() on another thread cannot use a freed connection.
• Every registered data channel observer leaked, along with the JNI global reference to the Java observer, which kept the whole closed channel reachable. It is now freed when it is replaced, unregistered, or the channel is disposed. A callback whose thread can no longer attach to the JVM is dropped instead of crashing.

The last two are ported from devopvoid/webrtc-java@8b77ec8, the first matches devopvoid/webrtc-java@40e538b.

Versions are named 1.0.4-ip.N. The Publish Packages workflow publishes them to this repository's GitHub Packages, with the native jars of a finished Build run, so a release does not rebuild WebRTC. It runs after each successful Build on master, or by hand with a Build run ID. Reading the packages needs a token with read:packages; Geyser's release uses its PACKAGES_TOKEN secret.

Differences from the Original Project

This stripped down version of the library removes audio and video support, focusing solely on data channels for peer-to-peer data exchange. It is intended for use cases where only data transfer is required, such as multiplayer gaming or real-time data synchronization. The removal of media capabilities results in a significantly smaller library size and increased portability.

It also adds support for ARM Windows systems, and has testing coverage for all platforms via GitHub Actions.

Usage

The base project is published under the group dev.kastle.webrtc and artifact webrtc-java. The native libraries are published under the same group and artifact with platform-specific classifiers:

• linux-x86_64
• linux-aarch32
• linux-aarch64
• windows-x86_64
• windows-aarch64
• macos-x86_64
• macos-aarch64

Maven Usage

<dependency>
    <groupId>dev.kastle.webrtc</groupId>
    <artifactId>webrtc-java</artifactId>
    <version>VERSION</version>
</dependency>
<dependency>
    <groupId>dev.kastle.webrtc</groupId>
    <artifactId>webrtc-java</artifactId>
    <version>VERSION</version>
    <classifier>PLATFORM-ARCH</classifier>
</dependency>

Gradle Usage (Groovy)

implementation 'dev.kastle.webrtc:webrtc-java:VERSION'
implementation 'dev.kastle.webrtc:webrtc-java:VERSION:PLATFORM-ARCH'

Gradle Usage (Kotlin DSL)

implementation("dev.kastle.webrtc:webrtc-java:VERSION")
implementation("dev.kastle.webrtc:webrtc-java:VERSION:PLATFORM-ARCH")

Note that the natives are not bundled with the main library, so you will need to appropriately include those that are needed for your project. If your project is an executable jar, you may want to read JEP-472. Because this project uses JNI, you may need to enable native access, depending on your Java version and execution environment. The main module is named dev.kastle.webrtc, and the natives modules are named dev.kastle.webrtc.natives.<platform> (e.g. dev.kastle.webrtc.natives.linux.x86_64), with any hyphens replaced by periods.

Development

The project has a preconfigured .vscode setup for easy development. Make sure to install the recommended extensions when prompted. Run the ./gradlew build command to build the project. Note that building the native libraries requires clang and cmake to be installed and on your path.

The initial build will take significant time to compile, as cloning the WebRTC source code brings in multiple other repo source trees from the Chromium project, requiring about 30 GB of disk space. On Windows, you may need to set WEBRTC_CHECKOUT_FOLDER to a shorter path to avoid exceeding file path length limits.

The version of WebRTC used can be changed by modifying the webrtc.branch property in webrtc-jni/gradle.properties. Note, however, that changing the version used will likely require updating the patches in webrtc-jni/src/main/cpp/dependencies/webrtc/patches/ to ensure successful compilation.

License

This copyright notice is maintained from the original project:

Copyright (c) 2019 Alex Andres

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](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.