Question

在拦截器下面尝试

import { Injectable } from '@angular/core';
import { HttpEvent, HttpInterceptor, HttpHandler, HttpRequest } from '@angular/common/http';

import { Observable } from 'rxjs/Observable';
import { finalize } from 'rxjs/operators';

@Injectable()
export class HttpRequestsInterceptor implements HttpInterceptor {

    requestQueue = [];
    reqCount: number = 0;
    reqFlag: boolean = false;
    prevCount: number = 0;
    obsIntrReq: any;

    intercept(req: HttpRequest<any>, next: HttpHandler):
        Observable<HttpEvent<any>> {
        this.prevCount++;
        if (this.prevCount >= 4) {
            this.requestQueue.push(req);
            this.obsIntrReq = Observable.interval(1000).do(() => {
                if (this.reqFlag) {                    
                    this.requestQueue.splice(0, 1);
                    return next.handle(this.requestQueue[0]);
                }
            })
                .switchMap(() => this.intervalPreviewChecking(this.reqCount, this.requestQueue.length))
                .subscribe(() => { });
        } else {
            return next.handle(req).pipe(
                finalize(() => {
                    this.prevCount--;
                })
            );
        }

    }

    intervalPreviewChecking(rCount, requestQueueLength) {
        if (requestQueueLength == 0) {
            this.prevCount = 0;
            this.reqFlag = false;
            this.obsIntrReq.unsubscribe();
            return this.obsIntrReq = null;
        }
        if (this.prevCount < 4) {
            this.reqFlag = true;
            return Observable.of(true);
        }
        this.reqFlag = false;
        return Observable.of(false);
    }
}

Answer 1

每次HTTP调用都会调用拦截器。

如果我必须优先考虑我的电话，我不会在拦截器中执行，而是在我的功能中。

这就是我要做的事情（order =请求的优先级）。

const calls: {order: number, call: any}[] = [];

calls.push({order: 0, call: this.myService.makeCall(0) });
calls.push({order: 1, call: this.myService.makeCall(1) });
// etc. 

const orderedCalls = calls.sort((a, b) => a.order - b.order).map(call => call.call);

Observable.forkJoin(orderedCalls);

Angular 4/5如何根据优先级

1 个答案: