Merge pull request #702 from GNS3/Basic-cache-for-some-of-the-services

Basic cache for some of the services

src/app/services/symbol.service.spec.ts

@@ -8,6 +8,7 @@ import { getTestServer } from './testing';
 import { SymbolService } from './symbol.service';
 import { Symbol } from '../models/symbol';
 import { AppTestingModule } from '../testing/app-testing/app-testing.module';
+import { of } from 'rxjs';
 
 describe('SymbolService', () => {
   let httpClient: HttpClient;
@@ -50,20 +51,11 @@ describe('SymbolService', () => {
   }));
 
   it('should load symbols', inject([SymbolService], (service: SymbolService) => {
-    service.load(server).subscribe();
+    spyOn(service, 'load').and.returnValue(of([]));
 
-    const req = httpTestingController.expectOne('http://127.0.0.1:3080/v2/symbols');
+    service.list(server).subscribe();
 
-    req.flush([{ symbol_id: 'myid' }]);
+    expect(service.load).toHaveBeenCalled();
-
-    const raw = httpTestingController.expectOne('http://127.0.0.1:3080/v2/symbols/myid/raw');
-    raw.flush('myraw');
-
-    service.symbols.subscribe(symbols => {
-      expect(symbols.length).toEqual(1);
-      expect(symbols[0].symbol_id).toEqual('myid');
-      expect(symbols[0].raw).toEqual('myraw');
-    });
   }));
 
   it('should get symbols', inject([SymbolService], (service: SymbolService) => {

src/app/services/symbol.service.ts

@@ -1,13 +1,17 @@
 import { Injectable } from '@angular/core';
-import { BehaviorSubject, forkJoin, Observable } from 'rxjs';
+import { BehaviorSubject, forkJoin, Observable, of } from 'rxjs';
 
 import { Symbol } from '../models/symbol';
 import { Server } from '../models/server';
 import { HttpServer } from './http-server.service';
+import { shareReplay } from 'rxjs/operators';
+
+const CACHE_SIZE = 1;
 
 @Injectable()
 export class SymbolService {
   public symbols: BehaviorSubject<Symbol[]> = new BehaviorSubject<Symbol[]>([]);
+  private cache: Observable<Symbol[]>;
 
   constructor(private httpServer: HttpServer) {}
 
@@ -16,25 +20,22 @@ export class SymbolService {
   }
 
   add(server: Server, symbolName: string, symbol: string) {
+    this.cache = null;
     return this.httpServer.post(server, `/symbols/${symbolName}/raw`, symbol)
   }
 
   load(server: Server): Observable<Symbol[]> {
-    const subscription = this.list(server).subscribe((symbols: Symbol[]) => {
+    return this.httpServer.get<Symbol[]>(server, '/symbols');
-      const streams = symbols.map(symbol => this.raw(server, symbol.symbol_id));
-      forkJoin(streams).subscribe(results => {
-        symbols.forEach((symbol: Symbol, i: number) => {
-          symbol.raw = results[i];
-        });
-        this.symbols.next(symbols);
-        subscription.unsubscribe();
-      });
-    });
-    return this.symbols.asObservable();
   }
 
   list(server: Server) {
-    return this.httpServer.get<Symbol[]>(server, '/symbols');
+    if(!this.cache) {
+      this.cache = this.load(server).pipe(
+        shareReplay(CACHE_SIZE)
+      );
+    }
+
+    return this.cache;
   }
 
   raw(server: Server, symbol_id: string) {