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AstrBot SDK v4 架构与实现文档

目录

  1. 架构概览
  2. 目录结构
  3. 核心模块详解
  4. 五大硬性协议规则
  5. 数据流与通信模型
  6. 扩展机制

架构概览

AstrBot SDK v4 采用分层架构设计,从上到下分为:

┌─────────────────────────────────────────────────────┐
│                    用户层 (User Layer)               │
│              插件开发者编写的 Star 类                 │
├─────────────────────────────────────────────────────┤
│                    API 层 (API Layer)                │
│     Star, Context, decorators, filter, events       │
├─────────────────────────────────────────────────────┤
│                 翻译层 (Translation Layer)           │
│     HandlerDispatcher, Loader, LegacyAdapter        │
├─────────────────────────────────────────────────────┤
│                通信层 (Communication Layer)          │
│        Peer, Transport, CapabilityRouter            │
└─────────────────────────────────────────────────────┘

核心设计原则

  1. 协议优先: 所有通信通过标准化的协议消息
  2. 能力抽象: 通过 Capability 系统暴露核心功能
  3. 双向通信: Plugin ↔ Core 的对称通信模型
  4. 向后兼容: LegacyAdapter 提供 v3 兼容层

目录结构

src-new/astrbot_sdk/
├── __init__.py              # 顶层导出
├── __main__.py              # CLI 入口点
├── cli.py                   # Click 命令行工具
├── star.py                  # Star 基类与 Handler 发现
├── context.py               # 运行时 Context 与 CancelToken
├── decorators.py            # 装饰器 @on_command, @on_message 等
├── events.py                # MessageEvent 事件定义
├── errors.py                # AstrBotError 错误模型
├── compat.py                # 兼容层导出
├── _legacy_api.py           # Legacy Context 与 CommandComponent
│
├── protocol/                # 协议层
│   ├── __init__.py
│   ├── descriptors.py       # HandlerDescriptor, CapabilityDescriptor
│   ├── messages.py          # 五种协议消息类型
│   └── legacy_adapter.py    # v3 JSON-RPC ↔ v4 协议转换
│
├── runtime/                 # 运行时层
│   ├── __init__.py
│   ├── peer.py              # 核心通信端点
│   ├── transport.py         # 传输层实现
│   ├── loader.py            # 插件加载器
│   ├── handler_dispatcher.py # Handler 分发器
│   ├── capability_router.py # Capability 路由器
│   └── bootstrap.py         # Supervisor/Worker 运行时
│
├── clients/                 # 客户端层
│   ├── __init__.py
│   ├── _proxy.py            # CapabilityProxy 代理
│   ├── llm.py               # LLM 客户端
│   ├── db.py                # 数据库客户端
│   ├── memory.py            # 记忆客户端
│   └── platform.py          # 平台客户端
│
└── api/                     # API 层
    ├── __init__.py
    ├── components/          # 组件导出
    │   ├── __init__.py
    │   └── command.py       # CommandComponent 导出
    ├── event/               # 事件相关
    │   ├── __init__.py
    │   └── filter.py        # filter 命名空间
    └── star/                # Star 相关
        ├── __init__.py
        └── context.py       # Legacy Context 导出

核心模块详解

协议层 (protocol/)

descriptors.py - 描述符定义

定义了 Handler 和 Capability 的元数据结构。

核心类型:

# 权限配置
class Permissions(_DescriptorBase):
    require_admin: bool = False
    level: int = 0

# 四种 Trigger 类型 (discriminated union)
class CommandTrigger:
    type: Literal["command"] = "command"
    command: str
    aliases: list[str] = []
    description: str | None = None

class MessageTrigger:
    type: Literal["message"] = "message"
    regex: str | None = None
    keywords: list[str] = []
    platforms: list[str] = []

class EventTrigger:
    type: Literal["event"] = "event"
    event_type: str

class ScheduleTrigger:
    type: Literal["schedule"] = "schedule"
    cron: str | None = None
    interval_seconds: int | None = None

# Trigger 联合类型
Trigger = Annotated[
    CommandTrigger | MessageTrigger | EventTrigger | ScheduleTrigger,
    Field(discriminator="type"),
]

# Handler 描述符
class HandlerDescriptor(_DescriptorBase):
    id: str
    trigger: Trigger
    priority: int = 0
    permissions: Permissions

# Capability 描述符
class CapabilityDescriptor(_DescriptorBase):
    name: str
    description: str
    input_schema: dict[str, Any] | None = None
    output_schema: dict[str, Any] | None = None
    supports_stream: bool = False
    cancelable: bool = False

messages.py - 协议消息

定义五种协议消息类型,遵循统一 id 字段原则。

消息类型:

类型 用途 关键字段
InitializeMessage 初始化握手 peer, handlers, metadata
InvokeMessage 调用 Capability capability, input, stream
ResultMessage 返回结果 success, output, error
EventMessage 流式事件 phase (started/delta/completed/failed)
CancelMessage 取消请求 reason

核心函数:

def parse_message(payload: str | bytes | dict) -> ProtocolMessage:
    """解析 JSON 为协议消息对象"""

legacy_adapter.py - 协议适配器

实现 v3 JSON-RPC 与 v4 协议的双向转换。

核心类:

class LegacyAdapter:
    def legacy_to_v4(self, payload) -> LegacyToV4Message:
        """Legacy JSON-RPC → v4 Message"""

    def legacy_request_to_message(self, payload) -> InitializeMessage | InvokeMessage | ...:
        """Legacy Request 转换"""

    def initialize_to_legacy_handshake_response(self, message) -> dict:
        """v4 Initialize → Legacy Response"""

    def invoke_to_legacy_request(self, message) -> dict:
        """v4 Invoke → Legacy Request"""

常量:

LEGACY_JSONRPC_VERSION = "2.0"
LEGACY_CONTEXT_CAPABILITY = "internal.legacy.call_context_function"
LEGACY_HANDSHAKE_METADATA_KEY = "legacy_handshake_payload"
LEGACY_ADAPTER_MESSAGE_EVENT = 3

运行时层 (runtime/)

peer.py - 核心通信端点

实现 Plugin ↔ Core 的对称通信模型。

核心方法:

class Peer:
    # 生命周期
    async def start(self) -> None: ...
    async def stop(self) -> None: ...

    # 初始化
    async def initialize(self, handlers, metadata) -> InitializeOutput: ...

    # Capability 调用
    async def invoke(self, capability, payload, stream=False) -> dict: ...
    async def invoke_stream(self, capability, payload) -> AsyncIterator[EventMessage]: ...

    # 取消
    async def cancel(self, request_id, reason="user_cancelled") -> None: ...

    # Handler 设置
    def set_initialize_handler(self, handler): ...
    def set_invoke_handler(self, handler): ...
    def set_cancel_handler(self, handler): ...

内部状态:

self._pending_results: dict[str, asyncio.Future[ResultMessage]]  # 普通调用
self._pending_streams: dict[str, asyncio.Queue]                  # 流式调用
self._inbound_tasks: dict[str, tuple[Task, CancelToken]]         # 入站任务

transport.py - 传输层实现

抽象传输层,支持多种通信方式。

类层次:

Transport (ABC)
├── StdioTransport        # 进程间通信 (stdin/stdout)
├── WebSocketServerTransport  # WebSocket 服务端
└── WebSocketClientTransport  # WebSocket 客户端

StdioTransport 特性:

  • 支持作为父进程启动子进程 (command 参数)
  • 支持直接读写 stdin/stdout
  • 自动处理进程生命周期

WebSocket 特性:

  • 心跳机制
  • 单连接限制 (Server 端)
  • 自动重连 (Client 端)

loader.py - 插件加载器

负责插件发现、环境准备和实例化。

核心类型:

@dataclass
class PluginSpec:
    name: str
    plugin_dir: Path
    manifest_path: Path
    requirements_path: Path
    python_version: str
    manifest_data: dict[str, Any]

@dataclass
class LoadedHandler:
    descriptor: HandlerDescriptor
    callable: Any
    owner: Any
    legacy_context: Any | None = None

@dataclass
class LoadedPlugin:
    plugin: PluginSpec
    handlers: list[LoadedHandler]
    instances: list[Any]

核心函数:

def discover_plugins(plugins_dir: Path) -> PluginDiscoveryResult:
    """扫描插件目录,发现所有有效插件"""

def load_plugin(plugin: PluginSpec) -> LoadedPlugin:
    """加载插件,返回 Handler 列表"""

class PluginEnvironmentManager:
    """使用 uv 管理插件虚拟环境"""
    def prepare_environment(self, plugin: PluginSpec) -> Path:
        """准备插件 Python 环境,返回 python 路径"""

Handler ID 格式:

{plugin_name}:{module}.{ClassName}.{method_name}

handler_dispatcher.py - Handler 分发器

处理 handler.invoke Capability 的调用。

class HandlerDispatcher:
    async def invoke(self, message, cancel_token) -> dict[str, Any]:
        """调用指定 Handler"""

    async def cancel(self, request_id: str) -> None:
        """取消正在执行的 Handler"""

    async def _run_handler(self, loaded, event, ctx) -> None:
        """执行 Handler处理同步/异步/生成器返回值"""

    def _build_args(self, handler, event, ctx) -> list[Any]:
        """根据签名注入 event 和 ctx 参数"""

参数注入规则:

参数名 注入值
event MessageEvent 实例
ctx / context Context 实例

capability_router.py - Capability 路由器

管理和路由 Capability 调用。

class CapabilityRouter:
    def register(self, descriptor, call_handler=None, stream_handler=None, exposed=True):
        """注册 Capability"""

    async def execute(self, capability, payload, stream, cancel_token, request_id):
        """执行 Capability 调用"""

@dataclass
class StreamExecution:
    iterator: AsyncIterator[dict[str, Any]]
    finalize: Callable[[list[dict]], dict[str, Any]]

内置 Capabilities:

Capability 功能
llm.chat 对话 (返回文本)
llm.chat_raw 对话 (返回完整响应)
llm.stream_chat 流式对话
memory.search 搜索记忆
memory.save 保存记忆
memory.delete 删除记忆
db.get 读取 KV
db.set 写入 KV
db.delete 删除 KV
db.list 列出 KV
platform.send 发送消息
platform.send_image 发送图片
platform.get_members 获取群成员

Capability 命名规则:

RESERVED_CAPABILITY_PREFIXES = ("handler.", "system.", "internal.")
CAPABILITY_NAME_PATTERN = r"^[a-z][a-z0-9_]*\.[a-z][a-z0-9_]*$"

bootstrap.py - 运行时启动器

定义三种运行模式。

运行模式:

模式 用途
Supervisor SupervisorRuntime 管理多插件,聚合 Handler
Worker PluginWorkerRuntime 单插件进程,处理 Handler 调用
WebSocket run_websocket_server() 开发调试用 WebSocket 服务
class WorkerSession:
    """Supervisor 管理的单插件会话"""
    async def start(self) -> None: ...
    async def invoke_handler(self, handler_id, event_payload, request_id) -> dict: ...

class SupervisorRuntime:
    """Supervisor 运行时"""
    async def start(self) -> None:
        # 1. 发现插件
        # 2. 为每个插件启动 Worker 进程
        # 3. 聚合 Handler 并向 Core 初始化

class PluginWorkerRuntime:
    """Worker 运行时"""
    async def start(self) -> None:
        # 1. 加载插件
        # 2. 创建 Dispatcher
        # 3. 向 Supervisor 初始化

客户端层 (clients/)

_proxy.py - Capability 代理

提供类型安全的 Capability 调用接口。

class CapabilityProxy:
    async def call(self, name: str, payload: dict) -> dict[str, Any]:
        """普通调用"""

    async def stream(self, name: str, payload: dict) -> AsyncIterator[dict[str, Any]]:
        """流式调用"""

llm.py - LLM 客户端

class LLMClient:
    async def chat(self, prompt, system=None, history=None, model=None, temperature=None) -> str:
        """简单对话,返回文本"""

    async def chat_raw(self, prompt, **kwargs) -> LLMResponse:
        """完整对话,返回结构化响应"""

    async def stream_chat(self, prompt, system=None, history=None) -> AsyncGenerator[str, None]:
        """流式对话"""

class LLMResponse(BaseModel):
    text: str
    usage: dict[str, Any] | None = None
    finish_reason: str | None = None
    tool_calls: list[dict[str, Any]] = []

db.py - 数据库客户端

class DBClient:
    async def get(self, key: str) -> dict[str, Any] | None: ...
    async def set(self, key: str, value: dict[str, Any]) -> None: ...
    async def delete(self, key: str) -> None: ...
    async def list(self, prefix: str | None = None) -> list[str]: ...

memory.py - 记忆客户端

class MemoryClient:
    async def search(self, query: str) -> list[dict[str, Any]]: ...
    async def save(self, key: str, value: dict[str, Any] | None = None, **extra) -> None: ...
    async def delete(self, key: str) -> None: ...

platform.py - 平台客户端

class PlatformClient:
    async def send(self, session: str, text: str) -> dict[str, Any]: ...
    async def send_image(self, session: str, image_url: str) -> dict[str, Any]: ...
    async def get_members(self, session: str) -> list[dict[str, Any]]: ...

API 层 (api/)

star.py - Star 基类

class Star:
    __handlers__: tuple[str, ...] = ()

    def __init_subclass__(cls, **kwargs):
        """收集子类的 Handler 方法名到 __handlers__"""

    async def on_start(self, ctx) -> None:
        """生命周期钩子:启动时"""

    async def on_stop(self, ctx) -> None:
        """生命周期钩子:停止时"""

    async def on_error(self, error, event, ctx) -> None:
        """错误处理钩子"""

    @classmethod
    def __astrbot_is_new_star__(cls) -> bool:
        return True  # 新版 Star 返回 True

Handler 发现机制:

  1. @on_command 等装饰器在方法上设置 __astrbot_handler_meta__
  2. Star.__init_subclass__ 遍历 MRO 收集带 meta 的方法名
  3. Loader 读取 __handlers__ 并构建 HandlerDescriptor

decorators.py - 装饰器

# 命令触发
@on_command("hello", aliases=["hi"], description="问候")
def hello_handler(event): ...

# 消息触发
@on_message(regex=r"^ping", keywords=["ping"], platforms=["qq"])
def ping_handler(event): ...

# 事件触发
@on_event("group_join")
def join_handler(event): ...

# 定时触发
@on_schedule(cron="0 9 * * *")  # 或 interval_seconds=60
def scheduled_handler(): ...

# 权限
@on_command("admin")
@require_admin
def admin_handler(event): ...

context.py - 运行时 Context

@dataclass
class CancelToken:
    def cancel(self) -> None: ...
    @property
    def cancelled(self) -> bool: ...
    async def wait(self) -> None: ...
    def raise_if_cancelled(self) -> None: ...

class Context:
    def __init__(self, *, peer, plugin_id, cancel_token=None, logger=None):
        self.llm = LLMClient(CapabilityProxy(peer))
        self.memory = MemoryClient(CapabilityProxy(peer))
        self.db = DBClient(CapabilityProxy(peer))
        self.platform = PlatformClient(CapabilityProxy(peer))
        self.plugin_id = plugin_id
        self.logger = logger or base_logger.bind(plugin_id=plugin_id)
        self.cancel_token = cancel_token or CancelToken()

events.py - 事件定义

@dataclass
class PlainTextResult:
    text: str

ReplyHandler = Callable[[str], Awaitable[None]]

class MessageEvent:
    def __init__(self, *, text, user_id, group_id, platform, session_id, raw, context, reply_handler):
        self.text = text
        self.user_id = user_id
        self.group_id = group_id
        self.platform = platform
        self.session_id = session_id or group_id or user_id or ""
        self.raw = raw or {}
        self._reply_handler = reply_handler

    @classmethod
    def from_payload(cls, payload, context=None, reply_handler=None) -> "MessageEvent":
        """从 payload 构造"""

    def to_payload(self) -> dict[str, Any]:
        """序列化为 payload"""

    async def reply(self, text: str) -> None:
        """回复消息 (依赖注入 reply_handler)"""

    def bind_reply_handler(self, reply_handler: ReplyHandler) -> None:
        """绑定回复处理器"""

    def plain_result(self, text: str) -> PlainTextResult:
        """创建纯文本结果"""

依赖注入模式:

# HandlerDispatcher 中
event = MessageEvent.from_payload(message.input.get("event", {}))
event.bind_reply_handler(lambda text: ctx.platform.send(event.session_id, text))

errors.py - 错误模型

@dataclass
class AstrBotError(Exception):
    code: str
    message: str
    hint: str = ""
    retryable: bool = False

    @classmethod
    def cancelled(cls, message="调用被取消") -> "AstrBotError": ...

    @classmethod
    def capability_not_found(cls, name: str) -> "AstrBotError": ...

    @classmethod
    def invalid_input(cls, message: str) -> "AstrBotError": ...

    @classmethod
    def protocol_version_mismatch(cls, message: str) -> "AstrBotError": ...

    @classmethod
    def protocol_error(cls, message: str) -> "AstrBotError": ...

    @classmethod
    def internal_error(cls, message: str) -> "AstrBotError": ...

    def to_payload(self) -> dict[str, object]: ...

    @classmethod
    def from_payload(cls, payload) -> "AstrBotError": ...

_legacy_api.py - 兼容层

class LegacyContext:
    """v3 Context 兼容实现"""
    def __init__(self, plugin_id: str):
        self.plugin_id = plugin_id
        self._runtime_context: NewContext | None = None
        self.conversation_manager = LegacyConversationManager(self)

    def bind_runtime_context(self, runtime_context: NewContext) -> None: ...

    async def llm_generate(self, chat_provider_id, prompt, ...) -> LLMResponse: ...
    async def tool_loop_agent(self, chat_provider_id, prompt, ...) -> LLMResponse: ...
    async def send_message(self, session, message_chain) -> None: ...
    async def put_kv_data(self, key, value) -> None: ...
    async def get_kv_data(self, key) -> dict | None: ...
    async def delete_kv_data(self, key) -> None: ...

class CommandComponent(Star):
    """v3 插件基类"""
    @classmethod
    def __astrbot_is_new_star__(cls) -> bool:
        return False  # 标识为旧版

api/event/filter.py - filter 命名空间

ADMIN = "admin"

def command(name: str):
    return on_command(name)

def regex(pattern: str):
    return on_message(regex=pattern)

def permission(level):
    if level == ADMIN:
        return require_admin
    return lambda func: func

class _FilterNamespace:
    command = staticmethod(command)
    regex = staticmethod(regex)
    permission = staticmethod(permission)

filter = _FilterNamespace()

核心文件

cli.py - 命令行接口

@click.group()
def cli(): ...

@cli.command()
@click.option("--plugins-dir", default="plugins")
def run(plugins_dir: Path):
    """启动 Supervisor"""
    asyncio.run(run_supervisor(plugins_dir=plugins_dir))

@cli.command(hidden=True)
@click.option("--plugin-dir", required=True)
def worker(plugin_dir: Path):
    """启动 Worker (内部命令)"""
    asyncio.run(run_plugin_worker(plugin_dir=plugin_dir))

@cli.command(hidden=True)
@click.option("--port", default=8765)
def websocket(port: int):
    """启动 WebSocket 服务 (调试用)"""

五大硬性协议规则

1. 统一 id 字段

规则: 所有协议消息必须有 id 字段。

class InitializeMessage(_MessageBase):
    type: Literal["initialize"] = "initialize"
    id: str  # 必须有
    ...

class ResultMessage(_MessageBase):
    type: Literal["result"] = "result"
    id: str  # 必须有
    ...

2. event 仅用于 stream=true

规则: EventMessage 只在流式调用中使用。

# Peer._handle_result
if queue is not None:  # stream=true 的 pending stream
    await queue.put(AstrBotError.protocol_error("stream=true 调用不应收到 result"))

# Peer._handle_event
if future is not None:  # stream=false 的 pending result
    future.set_exception(AstrBotError.protocol_error("stream=false 调用不应收到 event"))

3. handler.invoke 用于回调

规则: 插件 Handler 调用通过 handler.invoke Capability。

# HandlerDispatcher 中
if message.capability != "handler.invoke":
    raise AstrBotError.capability_not_found(message.capability)

4. cancel 作为 request-stop

规则: 取消请求发送 CancelMessage,等待终端事件。

async def cancel(self, request_id: str, reason: str = "user_cancelled") -> None:
    await self._send(CancelMessage(id=request_id, reason=reason))

# Worker 收到后
token.cancel()
task.cancel()

5. initialize 失败处理

规则: 初始化失败后连接进入不可用状态并关闭。

async def _reject_initialize(self, message, error):
    await self._send(ResultMessage(id=message.id, kind="initialize_result", success=False, error=...))
    self._unusable = True
    self._remote_initialized.set()
    await self.stop()

数据流与通信模型

初始化流程

┌────────┐                              ┌────────┐
│  Core  │                              │ Plugin │
└───┬────┘                              └───┬────┘
    │                                       │
    │──── InitializeMessage ───────────────>│
    │   {id, peer, handlers, metadata}      │
    │                                       │
    │<─── ResultMessage ────────────────────│
    │   {id, kind="initialize_result",      │
    │    success, output: {peer,            │
    │    capabilities, metadata}}           │
    │                                       │

Capability 调用流程 (普通)

┌────────┐                              ┌────────┐
│  Core  │                              │ Plugin │
└───┬────┘                              └───┬────┘
    │                                       │
    │──── InvokeMessage ───────────────────>│
    │   {id, capability, input, stream=false}│
    │                                       │
    │<─── ResultMessage ────────────────────│
    │   {id, success, output/error}         │
    │                                       │

Capability 调用流程 (流式)

┌────────┐                              ┌────────┐
│  Core  │                              │ Plugin │
└───┬────┘                              └───┬────┘
    │                                       │
    │──── InvokeMessage ───────────────────>│
    │   {id, capability, input, stream=true}│
    │                                       │
    │<─── EventMessage(phase="started") ────│
    │                                       │
    │<─── EventMessage(phase="delta") ──────│
    │   {data: {...}}                       │
    │<─── EventMessage(phase="delta") ──────│
    │   ...                                 │
    │                                       │
    │<─── EventMessage(phase="completed") ──│
    │   {output: {...}}                     │
    │                                       │

取消流程

┌────────┐                              ┌────────┐
│  Core  │                              │ Plugin │
└───┬────┘                              └───┬────┘
    │                                       │
    │──── CancelMessage ───────────────────>│
    │   {id, reason}                        │
    │                                       │
    │<─── EventMessage(phase="failed") ─────│
    │   {error: {code: "cancelled"}}        │
    │                                       │

扩展机制

添加新 Capability

  1. CapabilityRouter._register_builtin_capabilities() 中注册:
self.register(
    CapabilityDescriptor(
        name="my.custom_action",
        description="自定义操作",
        input_schema={"type": "object", "properties": {...}, "required": [...]},
        output_schema={"type": "object", "properties": {...}},
        supports_stream=False,
        cancelable=False,
    ),
    call_handler=my_handler,
    exposed=True,  # 是否暴露给对端
)

添加新 Trigger 类型

  1. descriptors.py 中定义新的 Trigger 类:
class CustomTrigger(_DescriptorBase):
    type: Literal["custom"] = "custom"
    custom_field: str
  1. 更新 Trigger 联合类型:
Trigger = Annotated[
    CommandTrigger | MessageTrigger | EventTrigger | ScheduleTrigger | CustomTrigger,
    Field(discriminator="type"),
]
  1. decorators.py 中添加装饰器:
def on_custom(custom_field: str):
    def decorator(func):
        meta = _get_or_create_meta(func)
        meta.trigger = CustomTrigger(custom_field=custom_field)
        return func
    return decorator

添加新 Transport

  1. 继承 Transport 基类:
class MyTransport(Transport):
    async def start(self) -> None: ...
    async def stop(self) -> None: ...
    async def send(self, payload: str) -> None: ...

版本兼容性

组件 v3 v4
插件基类 CommandComponent Star
Context LegacyContext Context
装饰器 @filter.command @on_command
协议 JSON-RPC 2.0 自定义协议
通信 单向 双向对称

兼容策略: LegacyAdapter 实现协议转换,CommandComponent 继承 Star 并标记 __astrbot_is_new_star__ = False