Modern Command Dispatch Architecture #97

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opened 2026-03-15 04:13:11 +00:00 by freemo · 0 comments

freemo commented

2026-03-15 04:13:11 +00:00

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Background and Context

The specification (§ Command Dispatch Router, § Action Middleware Pipeline) describes a
modern command dispatch system that replaces the current Wisper pub/sub fan-out pattern
with a trie-based command router and composable middleware pipeline.

Currently, player input is broadcast to ALL subscribed CommandHandler instances via
Wisper's :player_input event. Each handler independently regex-matches the input.
This is O(n) in the number of handlers and provides no centralized middleware for
cross-cutting concerns like permission checks, balance validation, or logging.

The specified architecture uses:

Trie-based router — O(k) lookup where k = command length, with self-registration
Middleware pipeline — before_action/after_action filters with priority ordering

Expected Behavior

All player commands dispatch through CommandRouter with O(k) lookup. Cross-cutting
concerns are handled by middleware rather than duplicated in each handler.

Acceptance Criteria

Trie-based CommandRouter replaces Wisper fan-out for command dispatch
Middleware pipeline handles permission, balance, position, cooldown checks
EventSourcingMiddleware centralizes ES event emission
All existing commands migrated to new registration pattern
All child Epics completed

Subtasks

Complete Epic: Trie-based Command Dispatch Router
Complete Epic: Action Middleware Pipeline

Definition of Done

This Legendary is complete when all child Epics are closed and their acceptance
criteria are satisfied.

## Background and Context The specification (§ Command Dispatch Router, § Action Middleware Pipeline) describes a modern command dispatch system that replaces the current Wisper pub/sub fan-out pattern with a trie-based command router and composable middleware pipeline. Currently, player input is broadcast to ALL subscribed `CommandHandler` instances via Wisper's `:player_input` event. Each handler independently regex-matches the input. This is O(n) in the number of handlers and provides no centralized middleware for cross-cutting concerns like permission checks, balance validation, or logging. The specified architecture uses: 1. **Trie-based router** — O(k) lookup where k = command length, with self-registration 2. **Middleware pipeline** — before_action/after_action filters with priority ordering ## Expected Behavior All player commands dispatch through `CommandRouter` with O(k) lookup. Cross-cutting concerns are handled by middleware rather than duplicated in each handler. ## Acceptance Criteria - Trie-based CommandRouter replaces Wisper fan-out for command dispatch - Middleware pipeline handles permission, balance, position, cooldown checks - EventSourcingMiddleware centralizes ES event emission - All existing commands migrated to new registration pattern - All child Epics completed ## Subtasks - [ ] Complete Epic: Trie-based Command Dispatch Router - [ ] Complete Epic: Action Middleware Pipeline ## Definition of Done This Legendary is complete when all child Epics are closed and their acceptance criteria are satisfied.