104 lines
3.3 KiB
TypeScript
104 lines
3.3 KiB
TypeScript
/**
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* HttpCache interceptor.
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* @file 缓存拦截器
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* @module interceptor/cache
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* @author Surmon <https://github.com/surmon-china>
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*/
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import { tap } from 'rxjs/operators'
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import { Observable, of } from 'rxjs'
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import { Reflector } from '@nestjs/core'
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import {
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HttpAdapterHost,
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NestInterceptor,
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ExecutionContext,
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CallHandler,
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Inject,
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Injectable,
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RequestMethod,
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} from '@nestjs/common'
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import { CacheService } from '~/processors/cache/cache.service'
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import * as SYSTEM from '~/constants/system.constant'
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import * as META from '~/constants/meta.constant'
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import { REDIS } from '~/app.config'
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import { IncomingMessage } from 'http'
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/**
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* @class HttpCacheInterceptor
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* @classdesc 弥补框架不支持单独定义 ttl 参数以及单请求应用的缺陷
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*/
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@Injectable()
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export class HttpCacheInterceptor implements NestInterceptor {
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constructor(
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private readonly cacheManager: CacheService,
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@Inject(SYSTEM.REFLECTOR) private readonly reflector: Reflector,
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@Inject(SYSTEM.HTTP_ADAPTER_HOST)
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private readonly httpAdapterHost: HttpAdapterHost,
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) {}
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// 自定义装饰器，修饰 ttl 参数
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async intercept(
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context: ExecutionContext,
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next: CallHandler<any>,
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): Promise<Observable<any>> {
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// 如果想彻底禁用缓存服务，则直接返回 -> return call$;
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const call$ = next.handle()
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if (REDIS.disableApiCache) {
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return call$
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}
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const handler = context.getHandler()
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const isDisableCache = this.reflector.get(META.HTTP_CACHE_DISABLE, handler)
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const key =
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this.trackBy(context) ||
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`api-cache:${
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(context.switchToHttp().getRequest() as IncomingMessage).url
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}`
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if (!key || isDisableCache) {
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return call$
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}
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const target = context.getHandler()
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const metaTTL = this.reflector.get(META.HTTP_CACHE_TTL_METADATA, target)
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const ttl = metaTTL || REDIS.httpCacheTTL
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try {
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const value = await this.cacheManager.get(key)
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return value
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? of(value)
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: call$.pipe(
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tap((response) => this.cacheManager.set(key, response, { ttl })),
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)
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} catch (error) {
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return call$
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}
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}
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/**
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* @function trackBy
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* @description 目前的命中规则是：必须手动设置了 CacheKey 才会启用缓存机制，默认 ttl 为 APP_CONFIG.REDIS.defaultCacheTTL
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*/
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trackBy(context: ExecutionContext): string | undefined {
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const request = context.switchToHttp().getRequest()
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const httpServer = this.httpAdapterHost.httpAdapter
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const isHttpApp = Boolean(httpServer?.getRequestMethod)
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const isGetRequest =
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isHttpApp &&
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httpServer.getRequestMethod(request) === RequestMethod[RequestMethod.GET]
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const cacheKey = this.reflector.get(
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META.HTTP_CACHE_KEY_METADATA,
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context.getHandler(),
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)
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const isMatchedCache = isHttpApp && isGetRequest && cacheKey
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// const requestUrl = httpServer.getRequestUrl(request);
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// console.log('isMatchedCache', isMatchedCache, 'requestUrl', requestUrl, 'cacheKey', cacheKey);
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// 缓存命中策略 -> http -> GET -> cachekey -> url -> undefined
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return isMatchedCache ? cacheKey : undefined
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/*
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return undefined;
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return isMatchedCache ? requestUrl : undefined;
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return isMatchedCache ? (cacheKey || requestUrl) : undefined;
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*/
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}
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}
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