X-Git-Url: https://juplo.de/gitweb/?a=blobdiff_plain;f=src%2Fapp%2Fhero.service.ts;h=349d043a10ee94158ddb3260ea18c6227f8329cc;hb=5c525c7b08b4ea57e94f1c8644297de8e443e2da;hp=d0801f302c28fedf0cd9c61e92addb21569b27ef;hpb=cdbcd5578c991169816c9b621c5a571ffdaefeb8;p=examples%2Fangular-tour-of-heroes

diff --git a/src/app/hero.service.ts b/src/app/hero.service.ts
index d0801f3..349d043 100644
--- a/src/app/hero.service.ts
+++ b/src/app/hero.service.ts
@@ -1,8 +1,10 @@
 import { Injectable } from '@angular/core';
-import { Observable, of } from 'rxjs';
+import { Observable, of, EMPTY } from 'rxjs';
 import { Hero } from './hero';
 import { HEROES } from './mock-heroes';
+import { HttpClient, HttpHeaders } from '@angular/common/http';
 import { MessageService } from './message.service';
+import { catchError, tap } from 'rxjs/operators';
 
 
 @Injectable({
@@ -10,9 +12,77 @@ import { MessageService } from './message.service';
 })
 export class HeroService {
 
-  constructor(private messageService : MessageService) { }
+  heroesUrl = 'api/heroes';  // URL to web api
+  httpOptions = {
+    headers: new HttpHeaders({ 'Content-Type': 'application/json' })
+  };
 
-  getHeroes() : Observable<Hero[]> {
-    return of(HEROES);
+  constructor(
+    private http: HttpClient,
+    private messageService: MessageService) { }
+
+  getHeroes(): Observable<Hero[]> {
+    this.log('fetching heroes...');
+    return this.http
+      .get<Hero[]>(this.heroesUrl)
+      .pipe(
+        tap((heroes: Hero[]) => this.log(`fetched ${heroes.length} heroes`)),
+        catchError(this.handleError<Hero[]>('getHeroes', []))
+      );
+  }
+
+  /** POST: add a new hero to the server */
+  addHero(hero: Hero): Observable<Hero> {
+    return this.http.post<Hero>(this.heroesUrl, hero, this.httpOptions).pipe(
+      tap((newHero: Hero) => this.log(`added hero w/ id=${newHero.id}`)),
+      catchError(this.handleError<Hero>('addHero'))
+    );
+  }
+
+  /** GET hero by id. Will 404 if id not found */
+  getHero(id: number): Observable<Hero> {
+    this.log(`requested hero id=${id}`);
+    const url = `${this.heroesUrl}/${id}`;
+    return this.http.get<Hero>(url).pipe(
+      tap(_ => this.log(`fetched hero id=${id}`)),
+      catchError(this.handleError<Hero>(`getHero id=${id}`))
+    );
+  }
+
+  /** PUT: update the hero on the server */
+  updateHero(hero: Hero): Observable<any> {
+    return this.http.put(this.heroesUrl, hero, this.httpOptions).pipe(
+      tap(_ => this.log(`updated hero id=${hero.id}`)),
+      catchError(this.handleError<any>('updateHero'))
+    );
+  }
+
+  /**
+   * Handle Http operation that failed.
+   * Let the app continue.
+   * @param operation - name of the operation that failed
+   * @param result - optional value to return as the observable result
+   */
+  private handleError<T>(operation = 'operation', result?: T) {
+    return (error: any): Observable<T> => {
+
+      // TODO: send the error to remote logging infrastructure
+      console.error(error); // log to console instead
+
+      // TODO: better job of transforming error for user consumption
+      this.log(`${operation} failed: ${error.message}`);
+
+      // Let the app keep running by returning an empty result.
+      if (result === undefined) {
+        return EMPTY as Observable<T>;
+      } else {
+        return of(result as T);
+      }
+    };
+  }
+
+  /** Log a HeroService message with the MessageService */
+  private log(message: string) {
+    this.messageService.add(`HeroService: ${message}`);
   }
 }