Introduction to Client Services

What is a Client Service?

Client Services are the backbone of the player's local experience in OpenCore. They encapsulate interaction with the GTA V engine, UI management, and local entity control. Unlike Server Services which handle global authority, Client Services focus on responsiveness, visuals, and local player interaction.

1. Automatic Injection

Just like on the server, OpenCore handles the lifecycle of client services automatically. By using the @Client.Controller() or @Server.Service() decorators, dependencies are resolved and injected into your constructor.

Key Rule:

• No manual instantiation: Never use new MyClientService().
• Constructor Injection: Define the service in your class constructor to receive the framework-managed instance.

@Client.Controller()
export class MyUIController {
  // NotificationService is automatically injected
  constructor(private readonly notification: NotificationService) {}

  @Client.Key('E')
  onPressE() {
    this.notification.show('You pressed E!')
  }
}

2. Environment Awareness

Client services are optimized for the high-frequency nature of the FiveM client. Many services include internal caching or optimized tick-based logic to ensure that gameplay remains smooth (maintaining high FPS).

3. Core Responsibilities

Client Services handle several critical areas:

• Streaming: Loading and unloading models, animations, and textures.
• Visuals: Managing blips, markers, and native notifications.
• Life Cycle: Handling the complex process of spawning and resurrecting the player.
• Interactions: Displaying progress bars and managing NUI communication.

4. Summary of Core Client Services

Service	Responsibility
SpawnService	Orchestrates the complete player spawn/respawn lifecycle.
NotificationService	Displays native GTA V notifications, help text, and subtitles.
BlipService	Manages map icons for entities, positions, and radii.
StreamingService	High-level API for requesting and releasing game assets (models, anims).
ProgressService	Displays progress bars with animation and prop support.
StreamingService	Efficient loading of models, animations, and particles.