41 lines
1.8 KiB
TypeScript
41 lines
1.8 KiB
TypeScript
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// services/api/src/realtime/contract-ws.adapter.ts —— 契约帧协议的 WS 适配器
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// （P2 Task 7）。@nestjs/platform-ws 的 WsAdapter 只分发 {event,data} 信封
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// 帧，而 P2 契约（@photo/contracts realtime.ts）的客户端消息是 {type,...}
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// 判别联合——本子类仅覆写 bindMessageHandler：按 frame.type 查处理映射，
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// 整帧作为载荷传入网关方法（@SubscribeMessage(type)），其余（同端口 HTTP
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// 挂载、upgrade 路由、关闭语义）全部继承 WsAdapter。非法 JSON / 非对象帧 /
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// 未知 type 静默丢弃（EMPTY）——协议层 error 帧只对「可理解但被拒绝」的
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// 消息（如 subscribe 校验失败）由网关显式返回。
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import { WsAdapter } from '@nestjs/platform-ws';
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import type { MessageMappingProperties } from '@nestjs/websockets/gateway-metadata-explorer';
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import { EMPTY, type Observable } from 'rxjs';
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export class ContractWsAdapter extends WsAdapter {
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override bindMessageHandler(
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buffer: { data?: unknown },
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handlersMap: Map<string, MessageMappingProperties>,
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transform: (data: unknown) => Observable<unknown>,
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): Observable<unknown> {
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let frame: unknown;
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try {
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frame = JSON.parse(String(buffer.data));
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} catch {
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return EMPTY;
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}
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if (typeof frame !== 'object' || frame === null) {
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return EMPTY;
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}
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const { type } = frame as { type?: unknown };
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if (typeof type !== 'string') {
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return EMPTY;
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}
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const handler = handlersMap.get(type);
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if (handler === undefined) {
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return EMPTY;
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}
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// 整帧作为载荷（网关方法按契约类型解构）；返回值经 transform 送回客户端
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// （返回 undefined/void 时上层 filter 掉，不发送——无应答语义的消息用此）。
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return transform(handler.callback(frame, type));
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}
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}
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