Angular中可以使用HttpInterceptor来进行API响应缓存。可以在服务中实现HttpInterceptor并在响应给客户端之前对响应进行缓存。这将减少API响应的加载时间,并大大提高应用程序的性能。
以下是一个示例,演示如何在Angular中使用HttpInterceptor来缓存API响应:
首先,创建一个服务类来实现HttpInterceptor接口:
import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';
import { Observable, of } from 'rxjs';
import { tap, shareReplay } from 'rxjs/operators';
@Injectable()
export class CacheInterceptor implements HttpInterceptor {
private cache = new Map>>();
constructor() {}
intercept(req: HttpRequest, next: HttpHandler): Observable> {
if (!req.headers.has('Cache-Control')) {
// 如果请求没有Cache-Control标头,则跳过缓存
return next.handle(req);
}
const cacheKey = req.urlWithParams;
if (this.cache.has(cacheKey)) {
return this.cache.get(cacheKey)!;
}
const reqClone = req.clone({ headers: req.headers.delete('Cache-Control') });
const httpEvent$ = next.handle(reqClone).pipe(
tap((response) => {
// 在收到响应时将其存储在缓存中
this.cache.set(cacheKey, of(response));
}),
shareReplay()
);
this.cache.set(cacheKey, httpEvent$);
return httpEvent$;
}
}
然后,在应用程序的根模块中注册此拦截器:
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpClientModule, HTTP_INTERCEPTORS } from '@angular/common/http';
import { AppComponent } from './app.component';
import { CacheInterceptor } from './cache.interceptor';
@NgModule({
declarations: [AppComponent],
imports: [BrowserModule, HttpClientModule],
providers: [
{
provide: HTTP