Overview

Thresh is a low-level infrastructure library for League Client API integration.

It provides composable transport, discovery, and event primitives. It does not provide high-level application orchestration.

Core API surfaces

Thresh exposes two primary abstractions designed to work together:

  1. ILcuHttpClient for resilient HTTP interactions
  2. IEventStream for real-time WAMP events (OnJsonApiEvent)

Package map

  • Thresh.Extensions — DI registration and core runtime composition
  • Thresh.Endpoints — optional typed endpoint groups over ILcuHttpClient
  • Thresh.Hosting — hosting/lifecycle integration for background processes
  • Thresh.HealthChecks — health check integration
  • Thresh.Reactive — optional reactive wrappers around event streams

Start with Thresh.Extensions, then add optional packages only where needed.

Architecture at a glance

  • Public abstractions: Thresh.Abstractions
  • Runtime implementation: Thresh.Core
  • DI integration: Thresh.Extensions

This separation keeps business logic independent from transport internals and improves testability.

Design principles

  • async-first APIs with CancellationToken support
  • DI-first composition
  • resilience defaults via Polly v8 retry and circuit-breaker strategies
  • observability hooks via ILogger, Meter, and ActivitySource("Thresh")
  • strict local trust model for authenticated LCU communication

Event model

IEventStream manages connection lifecycle and reconnection, and emits:

  • RawMessage for raw WAMP payloads
  • Message for parsed LeagueEventEnvelope values
  • Reconnected when a connection is re-established

Subscriptions are available by:

  • exact URI (Subscribe(string uri, ...))
  • regex pattern (Subscribe(Regex pattern, ...))
  • typed payload (Subscribe<T>(..., withSnapshot: true|false))

Platform and discovery model

  • Official support targets Windows and macOS.
  • Other environments (including Linux/Wine/Proton variants) are best-effort.
  • Use LCU_LOCKFILE explicitly for non-standard layouts.

Lockfile resolution is deterministic:

  1. LCU_LOCKFILE override
  2. cached lockfile path (if valid)
  3. process-derived candidates
  4. known install paths per platform

Boundary reminder

Thresh stays intentionally focused on reliable primitives.

Higher-level workflows, state machines, and domain orchestration should live in consumer code or optional packages.