fantasy-net

name

fantasy-net

description

This guide applies to development and code review for Fantasy / Fantasy.Net / Fantasy.Unity written in C#. Use it when a task involves Fantasy server code or Unity client code using Fantasy, ECS entities/components/systems, scenes and subscenes, FTask, network handlers/messages/protocols, Address or Roaming routing, cross-server events and subscriptions, Fantasy.config, scene or database access, HTTP controllers/services, session or client connection logic, or distributed runtime architecture. It may also be used for Fantasy-related code review, troubleshooting, compliance checks, risk analysis, and best practices, even when the user does not explicitly mention Fantasy.

Fantasy-net

Fantasy is a high-performance C# distributed game server framework based on ECS architecture, using FTask for async operations.

Core Principles

Fantasy Technical Specifications

• Use FTask for all async operations, not Task
• Separate Entity data from logic (Handler/System); multi-assembly projects must separate to support hot reload
• All registration is done at compile-time by source generators; don't manually register, don't modify .g.cs
• Entities, components, and Handlers use sealed class; all classes except structs must be created via Entity
• Use file-scoped namespaces (namespace Fantasy;)
• Use Log.Debug/Info/Error() for logging; return error codes via response.ErrorCode; business logic should not throw exceptions
• Use Event system for module decoupling: publish events instead of direct calls; prefer Struct events (zero GC), use Entity events for complex logic; use EventSystem for sync, AsyncEventSystem for async
• Strictly follow SOLID principles

Development Behavioral Guidelines

Tradeoff: These guidelines bias toward caution over speed. For trivial tasks, use judgment.

See references/guidelines-examples.md for detailed Fantasy scenario examples.

1. Think Before Coding

Don't assume. Don't hide confusion. Surface tradeoffs.

Before implementing:

• State your assumptions explicitly. If uncertain, ask.
• If multiple interpretations exist, present them - don't pick silently.
• If a simpler approach exists, say so. Push back when warranted.
• If something is unclear, stop. Name what's confusing. Ask.

Fantasy Key Points: Before implementing, clarify: architecture pattern (single-server/distributed), Entity ownership (which Scene), communication method (Roaming/Address/SphereEvent), configuration state (whether Fantasy.config has relevant nodes configured). When uncertain, ask; don't assume.

2. Simplicity First

Minimum code that solves the problem. Nothing speculative.

• No features beyond what was asked.
• No abstractions for single-use code.
• No "flexibility" or "configurability" that wasn't requested.
• No error handling for impossible scenarios.
• If you write 200 lines and it could be 50, rewrite it.

Ask yourself: "Would a senior engineer say this is overcomplicated?" If yes, simplify.

Fantasy Key Points: Avoid premature abstraction of Entity/Component structures; don't design factory/strategy patterns for single scenarios. When users only need basic functionality, write Component + necessary AwakeSystem directly; refactor when extension is needed.

3. Surgical Changes

Touch only what you must. Clean up only your own mess.

When editing existing code:

• Don't "improve" adjacent code, comments, or formatting.
• Don't refactor things that aren't broken.
• Match existing style, even if you'd do it differently.
• If you notice unrelated dead code, mention it - don't delete it.

When your changes create orphans:

• Remove imports/variables/functions that YOUR changes made unused.
• Don't remove pre-existing dead code unless asked.

The test: Every changed line should trace directly to the user's request.

Fantasy Key Points: Never modify .g.cs generated files (if you find issues, modify source files and regenerate). Don't manually adjust source generator registration code. Don't "optimize" existing Entity/Component structures unless user explicitly requests refactoring.

4. Goal-Driven Execution

Define success criteria. Loop until verified.

Transform tasks into verifiable goals:

• "Add validation" → "Write tests for invalid inputs, then make them pass"
• "Fix the bug" → "Write a test that reproduces it, then make it pass"
• "Refactor X" → "Ensure tests pass before and after"

For multi-step tasks, state a brief plan:

1. [Step] → verify: [check]
2. [Step] → verify: [check]
3. [Step] → verify: [check]

Strong success criteria let you loop independently. Weak criteria ("make it work") require constant clarification.

Fantasy Key Points: Define verifiable steps and criteria: protocol export (dotnet fantasy-export successfully generates .g.cs), compilation passes (dotnet build with no errors), Handler registration (check generated registration code), message flow (Log.Debug outputs key nodes, confirm request/response correctness).

Reference File Navigation

Read the corresponding file based on the requirement; for complex tasks, read multiple files.

File	When to Use
references/ecs/index.md	ECS entry: routes to Scene / SubScene / Entity definition / component operations / object pool / lifecycle; shared by server and Unity; read this first when Entity definition, component management, or ECS mechanism selection is involved
references/review.md	Fantasy code review entry: routes checks by ECS / Event / Timer / Protocol / Roaming / SphereEvent / HTTP / Database / Config; read this first when user wants review, code check, or Fantasy compliance verification
references/guidelines-examples.md	Development behavioral guidelines Fantasy scenario examples: Think Before Coding (clarify assumptions), Simplicity First (avoid over-engineering), Surgical Changes (precise modifications), Goal-Driven Execution (verifiable goals) with detailed comparison cases; read when understanding guideline application in Fantasy, or when code review reveals guideline violations
references/ecs/scene.md	Scene is the container and lifecycle boundary for all Entity/Component: cascade destruction when Scene disposes, OnCreateScene event, access system components via self.Scene (TimerComponent/EventComponent/NetworkMessagingComponent etc.); read when Scene concept, Scene initialization, OnCreateScene event, or Entity ownership is involved
references/ecs/ecs-check.md	ECS review checklist: Entity / Component / System / Scene / object pool / lifecycle common issues; read when user wants to check ECS code for Fantasy compliance
references/timer/index.md	Timer entry: routes to async wait / callback timers / event integration / best practices; read first when user needs delayed execution, repeated tasks, countdown, Wait, OnceTimer, RepeatedTimer
references/timer/implement.md	Timer implementation: FTask.Wait, WaitTill, WaitFrame, OnceTimer, RepeatedTimer, cancel timers; read only when directly writing Timer code
references/timer/event.md	Timer and Event integration: event-based timers, hot reload differences, when to use events instead of Action; read only when hot-reload-friendly Timer logic is needed
references/timer/best-practices.md	Timer best practices and troubleshooting: performance tips, common errors, Scene destruction, precision, cancel strategies; read only when optimizing or troubleshooting Timer code
references/ecs/subscene.md	SubScene dynamic child scenes: lightweight isolated spaces created at runtime from parent Scene, sharing parent Scene core components but with independent entity lists; Scene.CreateSubScene() API details (params, callback execution order), sending Address messages to SubScene, using Addressable on SubScene, destroying SubScene; read when needing instances, match rooms, instanced maps, dynamic battlefields, player private spaces, or on-demand scene creation/destruction
references/ecs/lifecycle.md	ECS lifecycle Systems: AwakeSystem, UpdateSystem, DestroySystem, DeserializeSystem, TransferOutSystem/TransferInSystem (cross-server transfer only) and trigger order; read when responding to Entity lifecycle events
references/event/index.md	Event entry: determine whether to use EventAwaiter or Event, then follow Workflow to corresponding doc; read first when requirement involves "wait for result" or "publish event" mechanism selection
references/event/event-awaiter.md	EventAwaiter entry: routes to implementation / modeling / troubleshooting; read first when user needs to wait for a condition, wait for player action, do request-response async flow, or explicitly mentions EventAwaiter/EventAwaiterComponent
references/event/struct-event.md	Struct event full workflow: Step 1 define event → Step 2 create listener → Step 3 publish event; recommended for most scenarios, read when creating Struct events
references/event/entity-event.md	Entity event full workflow: Step 1 create listener → Step 2 publish existing Entity (note isDisposed param); read only when passing existing Entity
references/event/check-event.md	Event system code review: Struct event checklist, Entity event checklist, listener checklist, common error comparisons; read when checking existing event code
references/server/setup-server.md	Create new Fantasy server project, integrate Fantasy into existing project (.NET/NuGet), three-layer structure setup, logging system quick config
references/unity/index.md	Unity client entry: routes to installation, connection, Session, receiving pushes; read first when Fantasy Unity client is involved
references/unity/unity-check.md	Unity review checklist: version consistency, compile macros, connection methods, Session usage, push Handler common issues; read when user wants to check Unity client code
references/unity/setup-unity.md	Unity client install Fantasy.Unity, configure compile symbols, import protocols; read only during installation or initial integration
references/unity/unity-connection.md	Unity client connect to server: FantasyRuntime component, scene.Connect, Runtime.Connect, protocol selection; read only during connection initialization
references/unity/unity-session.md	Unity client Session usage: send messages, RPC, connection holding, disconnect; read only for how to send messages after connection
references/logging.md	Logging system details: Fantasy.NLog full config, Fantasy config or add logging, NLog.config explanation, custom ILog implementation (Serilog/file logging etc.)
references/logging-check.md	Logging review checklist: logging initialization, NLog rules, config copy, mode switching, custom ILog common issues; read when user wants to check logging integration
references/protocol/index.md	Protocol entry: define .proto, export C#, install export tool routing; read first when .proto, Outer/Inner, protocol export is involved
references/protocol/protocol-check.md	Protocol review checklist: Outer/Inner selection, interface matching, naming, export, Handler alignment; read when user wants to check protocol or Handler definitions
references/protocol/define.md	Protocol definition entry: locate protocol root directory and route to Outer/Inner; read when creating new protocol files or determining where to place protocols
references/protocol/define-outer.md	Outer protocol: client↔server messages, IMessage / IRequest / IResponse; read only when defining Outer protocols
references/protocol/define-inner.md	Inner protocol: server↔server messages, IAddressMessage / IAddressRequest / IAddressResponse; read only when defining Inner protocols
references/protocol/define-common.md	Protocol common features: fields, collections, Map, enums, serialization, code injection; read only when field or serialization details are needed
references/protocol/export.md	Protocol export: check tool, run export, verify results; read after protocol definition is complete or when user requests re-export
references/protocol/export-install.md	Export tool installation and ExporterSettings.json configuration; read when tool is not installed or paths are not configured
references/server/server-message-handler.md	Server-side Handler for client messages, only for messages implementing IMessage/IRequest/IResponse interfaces; Message<T>/MessageRPC<TReq,TRes> templates, reply() usage, error code patterns, Session push; see respective files for Addressable/Roaming
references/server/server-message-handler-check.md	Server message Handler review checklist: base class selection, error codes, reply(), Session lifecycle, duplicate Handler common issues; read when user wants to check client message Handlers
references/unity/unity-message-handler.md	Unity client Handler for server push messages: Message<Session,T>, file location conventions, compile verification; read when user needs to create a Handler in Unity to receive server messages
references/server/address.md	Server-to-server messaging based on Entity.Address (RuntimeId): only for messages implementing IAddressMessage/IAddressRequest/IAddressResponse interfaces; read when defining Address message Handlers
references/server/address-check.md	Address review checklist: message patterns, entry address retrieval, Handler types, first communication and cached address common errors; read when user wants to check Address code
references/server/sphere-event/index.md	SphereEvent entry: cross-server domain events, subscribe, publish, unsubscribe, choosing between Event/Roaming; read first when cross-server event notifications, SphereEventComponent, SphereEventArgs, SphereEventSystem are involved
references/server/sphere-event/implement.md	SphereEvent implementation: define event class, implement handler, subscribe to remote events, publish events, unsubscribe; read only when directly writing SphereEvent code
references/server/sphere-event/best-practices.md	SphereEvent best practices and troubleshooting: object pool, hot reload, event size, disconnect cleanup, differences from Event/Roaming; read only when optimizing or troubleshooting SphereEvent logic
references/server/roaming/index.md	Roaming concept entry: core concepts (SessionRoamingComponent/Terminus/RoamingType) and Workflow decision tree; read this first, then sub-files as needed
references/server/roaming/roaming-check.md	Roaming review checklist: protocol, link establishment, Terminus lifecycle, message flow, transfer common issues; read when user wants to check Roaming code
references/server/roaming/protocol.md	Define roaming protocols: RoamingType.Config configuration, IRoamingMessage/IRoamingRequest/IRoamingResponse format; read only when defining protocols and adding roaming types or servers
references/server/roaming/setup.md	Establish roaming routes: Gate-side TryCreateRoaming/Link, parameter passing; read only when establishing routes
references/server/roaming/on-create-terminus.md	OnCreateTerminus event: event parameters, LinkTerminusEntity API, Args memory management rules, independent Handler implementation per server; read only when handling Terminus creation/reconnection
references/server/roaming/on-dispose-terminus.md	OnDisposeTerminus event: trigger timing, DisposeTerminusType distinction, independent Handler implementation per server; read only when handling Terminus disposal
references/server/roaming/handler.md	Roaming Handler entry: routes to message handling / push / cross-server send / transfer; read first when user wants to write Roaming Handlers or do transfers
references/server/roaming/messaging.md	Roaming message handling: client send, Gate proactive send to backend, Roaming Handler, backend push to client, cross-server send; read only when implementing message flow
references/server/roaming/transfer.md	Terminus transfer: StartTransfer, TransferOutSystem, TransferInSystem, lifecycle and considerations; read only when implementing cross-server transfer
references/server/roaming/error-codes.md	Roaming error codes: meanings and troubleshooting methods; read only when encountering Roaming-related errors
references/http.md	HTTP entry: routes to server configuration events and Controller writing; read first when HTTP server, Controller, OnConfigureHttpServices, OnConfigureHttpApplication are involved
references/http-check.md	HTTP review checklist: service configuration phase, middleware order, SceneContextFilter, return patterns, route mapping common issues; read when user wants to check HTTP code
references/http-server.md	HTTP server configuration: OnConfigureHttpServices, OnConfigureHttpApplication, authentication, authorization, CORS, middleware; read only when configuring HTTP services and middleware
references/http-controller.md	HTTP Controller writing: SceneContextFilter, Scene injection, Action return values, thread switching, Controller examples; read only when writing or troubleshooting Controllers
references/database/index.md	Database entry: MongoDB configuration, getting database instance, persistence, queries, indexes, concurrent modification routing; read first when MongoDB, IDatabase, scene.World.Database, data persistence is involved
references/database/database-check.md	Database review checklist: scene.World access, ISupportedSerialize, isDeserialize, coroutine locks, SeparateTable applicability; read when user wants to check database code
references/database/mongodb.md	MongoDB usage: ISupportedSerialize, Save, Insert, Query, Remove, indexes, isDeserialize, concurrent modification; read only when directly writing database code
references/database/separate-table.md	SeparateTable separate storage: aggregate entity split storage, [SeparateTable], PersistAggregate, LoadWithSeparateTables; read only when aggregate entity child data is too large and needs table separation optimization
references/database/best-practices.md	MongoDB best practices and troubleshooting: config association, query optimization, save strategies, common issues; read only when optimizing or troubleshooting database logic
references/config.md	Fantasy.config entry: routes by "add machine / process / World / Scene / database / port"; read first when Fantasy.config is involved
references/config-check.md	Fantasy.config review checklist: machine/process/world/scene/database reference relationships, ports, World mode ID range common issues; read when user wants to check configuration correctness
references/config-scenarios.md	Fantasy.config common scenarios: new project, add/remove Scene, change database, change port, multi-zone; read when modifying config for specific scenarios
references/server/setup-server-check.md	Server project integration review checklist: three-layer structure, target framework, Fantasy-Net reference, compile macros, AssemblyHelper, Program entry common issues; read when user wants to check server project Fantasy integration
templates/Fantasy.config	Full annotated template: all nodes, attributes, possible values, and examples; read only when writing actual XML