refactored requestCacheReducer

src/app/core/cache/response-cache.service.ts

@@ -0,0 +1,87 @@
+import { Injectable } from "@angular/core";
+import { Store } from "@ngrx/store";
+import {
+  ResponseCacheState, ResponseCacheEntry
+} from "./response-cache.reducer";
+import { Observable } from "rxjs";
+import { hasNoValue } from "../../shared/empty.util";
+import {
+  ResponseCacheRemoveAction,
+  ResponseCacheAddAction
+} from "./response-cache.actions";
+import { Response } from "./response-cache.models";
+
+/**
+ * A service to interact with the response cache
+ */
+@Injectable()
+export class ResponseCacheService {
+  constructor(
+    private store: Store<ResponseCacheState>
+  ) {}
+
+  add(key: string, response: Response, msToLive: number): Observable<ResponseCacheEntry> {
+      if (!this.has(key)) {
+        // this.store.dispatch(new ResponseCacheFindAllAction(key, service, scopeID, paginationOptions, sortOptions));
+        this.store.dispatch(new ResponseCacheAddAction(key, response, new Date().getTime(), msToLive));
+      }
+    return this.get(key);
+  }
+
+  /**
+   * Get an observable of the response with the specified key
+   *
+   * @param key
+   *    the key of the response to get
+   * @return Observable<ResponseCacheEntry>
+   *    an observable of the ResponseCacheEntry with the specified key
+   */
+  get(key: string): Observable<ResponseCacheEntry> {
+    return this.store.select<ResponseCacheEntry>('core', 'cache', 'response', key)
+      .filter(entry => this.isValid(entry))
+      .distinctUntilChanged()
+  }
+
+  /**
+   * Check whether the response with the specified key is cached
+   *
+   * @param key
+   *    the key of the response to check
+   * @return boolean
+   *    true if the response with the specified key is cached,
+   *    false otherwise
+   */
+  has(key: string): boolean {
+    let result: boolean;
+
+    this.store.select<ResponseCacheEntry>('core', 'cache', 'response', key)
+      .take(1)
+      .subscribe(entry => result = this.isValid(entry));
+
+    return result;
+  }
+
+  /**
+   * Check whether a ResponseCacheEntry should still be cached
+   *
+   * @param entry
+   *    the entry to check
+   * @return boolean
+   *    false if the entry is null, undefined, or its time to
+   *    live has been exceeded, true otherwise
+   */
+  private isValid(entry: ResponseCacheEntry): boolean {
+    if (hasNoValue(entry)) {
+      return false;
+    }
+    else {
+      const timeOutdated = entry.timeAdded + entry.msToLive;
+      const isOutDated = new Date().getTime() > timeOutdated;
+      if (isOutDated) {
+        this.store.dispatch(new ResponseCacheRemoveAction(entry.key));
+      }
+      return !isOutDated;
+    }
+  }
+
+}