111 lines
3.3 KiB
TypeScript
111 lines
3.3 KiB
TypeScript
import { Injectable } from '@angular/core';
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import { Hero } from './hero';
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import { MessageService } from './message.service';
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import { HttpClient, HttpHeaders } from '@angular/common/http';
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import { catchError, map, tap } from 'rxjs/operators';
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import { Observable, of } from 'rxjs';
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@Injectable({
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providedIn: 'root'
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})
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export class HeroService {
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private heroesUrl = 'api/heroes'; // URL to web api
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httpOptions = {
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headers: new HttpHeaders({ 'Content-Type': 'application/json' })
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};
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constructor(
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private http: HttpClient,
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private messageService: MessageService)
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{ }
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/** GET heroes from the server */
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getHeroes(): Observable<Hero[]> {
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return this.http.get<Hero[]>(this.heroesUrl)
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.pipe(
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tap(_ => this.log('fetched heroes')),
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catchError(this.handleError<Hero[]>('getHeroes', []))
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);
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}
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/** GET hero by id. Will 404 if id not found */
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getHero(id: number): Observable<Hero> {
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const url = `${this.heroesUrl}/${id}`;
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return this.http.get<Hero>(url).pipe(
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tap(_ => this.log(`fetched hero id=${id}`)),
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catchError(this.handleError<Hero>(`getHero id=${id}`))
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);
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}
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/** PUT: update the hero on the server */
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updateHero(hero: Hero): Observable<any> {
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return this.http.put(this.heroesUrl, hero, this.httpOptions).pipe(
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tap(_ => this.log(`updated hero id=${hero.id}`)),
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catchError(this.handleError<any>('updateHero'))
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);
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}
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/** POST: add a new hero to the server */
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addHero(hero: Hero): Observable<Hero> {
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return this.http.post<Hero>(this.heroesUrl, hero, this.httpOptions).pipe(
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tap((newHero: Hero) => this.log(`added hero w/ id=${newHero.id}`)),
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catchError(this.handleError<Hero>('addHero'))
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);
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}
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/** DELETE: delete the hero from the server */
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deleteHero(id: number): Observable<Hero> {
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const url = `${this.heroesUrl}/${id}`;
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return this.http.delete<Hero>(url, this.httpOptions).pipe(
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tap(_ => this.log(`deleted hero id=${id}`)),
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catchError(this.handleError<Hero>('deleteHero'))
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);
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}
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/* GET heroes whose name contains search term */
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searchHeroes(term: string): Observable<Hero[]> {
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if (!term.trim()) {
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// if not search term, return empty hero array.
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return of([]);
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}
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return this.http.get<Hero[]>(`${this.heroesUrl}/?name=${term}`)
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.pipe(
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tap(x => x.length ?
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this.log(`found heroes matching "${term}"`) :
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this.log(`no heroes matching "${term}"`)),
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catchError(this.handleError<Hero[]>('searchHeroes', []))
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);
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}
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/**
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* Handle Http operation that failed.
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* Let the app continue.
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*
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* @param operation - name of the operation that failed
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* @param result - optional value to return as the observable result
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*/
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private handleError<T>(operation = 'operation', result?: T) {
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return (error: any): Observable<T> => {
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// TODO: send the error to remote logging infrastructure
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console.error(error); // log to console instead
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// TODO: better job of transforming error for user consumption
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this.log(`${operation} failed: ${error.message}`);
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// Let the app keep running by returning an empty result.
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return of(result as T);
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};
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}
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/** Log a HeroService message with the MessageService */
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private log(message: string) {
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this.messageService.add(`HeroService: ${message}`);
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}
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}
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