From fd32ae5dcce556a576703359481785340ecd0a94 Mon Sep 17 00:00:00 2001
From: ChrisChen <yuanson.chen@gmail.com>
Date: Mon, 3 Nov 2025 17:10:18 +0000
Subject: [PATCH] Update src/app/services/crudServices/crud.service.ts

---
 src/app/services/crudServices/crud.service.ts | 162 ++++++++++++++++++
 1 file changed, 162 insertions(+)

diff --git a/src/app/services/crudServices/crud.service.ts b/src/app/services/crudServices/crud.service.ts
index 6021d75..ee372a5 100644
--- a/src/app/services/crudServices/crud.service.ts
+++ b/src/app/services/crudServices/crud.service.ts
@@ -178,3 +178,165 @@ export class CombinedKeyCrudService<T> implements ICrudService<T> {
   }
 
 } 
+// Type definitions
+type TextResponse = { message: string };
+/**
+* Base CRUD service that targets the provided controller path.
+*
+* It mirrors the endpoints of CrudBaseApiController<T>:
+* GET /api/{controller}
+* GET /api/{controller}/{id}
+* POST /api/{controller} -> string
+* POST /api/{controller}/batch -> string[]
+* PUT /api/{controller}
+* PUT /api/{controller}/batch -> number
+* DELETE /api/{controller}/{id}
+* DELETE /api/{controller}/batch -> text summary
+* GET /api/{controller}/{id}/exists -> boolean
+* GET /api/{controller}/count -> number
+*/
+@Injectable({ providedIn: 'root' })
+export class CrudBaseApiService<T extends object> {
+    /**
+    * Example: baseUrl = 'https://your-api', controller = 'Customer' →
+    * endpoint = 'https://your-api/api/Customer'
+    */
+    protected readonly endpoint: string;
+
+
+    /**
+    * @param http Angular HttpClient
+    * @param baseUrl API root without trailing slash (e.g., environment.apiBaseUrl)
+    * @param controllerName Controller name (e.g., 'Customer', 'Orders')
+    */
+    constructor(
+        protected http: HttpClient,
+        protected apiConfig: ApiConfigService,
+        @Inject(String) private controllerName: string
+    ) {
+        this.endpoint = apiConfig.getApiUrl(this.controllerName);
+    }
+
+
+    /** Optional default headers (JSON). Override in subclasses if needed. */
+    protected get jsonHeaders(): HttpHeaders {
+        return new HttpHeaders({ 'Content-Type': 'application/json' });
+    }
+
+
+    /** Shared error handler that surfaces useful messages. */
+    protected handleError(error: HttpErrorResponse): Observable<never> {
+        let msg = 'Unknown error';
+        if (error.error instanceof Blob) {
+            // In case backend returns text/plain; charset=utf-8 as Blob
+            return throwError(() => new Error('Server returned an error blob'));
+        }
+        if (typeof error.error === 'string') msg = error.error;
+        else if (error.error?.message) msg = error.error.message;
+        else if (error.message) msg = error.message;
+        return throwError(() => new Error(msg));
+    }
+    /** Prepare the response for the given entity. Override in subclasses if needed. */
+    protected prepareResponse(response: T): T {
+        // Do nothing by default
+        return response;
+    }
+
+    /** GET /api/{controller} */
+    getAll(): Observable<T[]> {
+        return this.http
+            .get<T[]>(this.endpoint)
+            .pipe(
+                map(response => {
+
+                    for (let i = 0; i < response.length; i++) {
+                        const element = response[i];
+                        response[i] = this.prepareResponse(element);
+                    }
+                    return response;
+                }),
+                catchError(err => this.handleError(err)));
+    }
+
+
+    /** GET /api/{controller}/{id} */
+    getById(id: string): Observable<T> {
+        return this.http
+            .get<T>(`${this.endpoint}/${id}`)
+            .pipe(
+                map(response => this.prepareResponse(response)),
+                catchError(err => this.handleError(err)));
+    }
+
+
+
+    /** POST /api/{controller} -> string */
+    create(entity: T): Observable<string> {
+        return this.http
+            .post<string>(this.endpoint, entity, { headers: this.jsonHeaders })
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** POST /api/{controller}/batch -> string[] */
+    createRange(entities: T[]): Observable<string[]> {
+        return this.http
+            .post<string[]>(`${this.endpoint}/batch`, entities, { headers: this.jsonHeaders })
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** PUT /api/{controller} */
+    update(entity: T): Observable<void> {
+        return this.http
+            .put<void>(this.endpoint, entity, { headers: this.jsonHeaders })
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** PUT /api/{controller}/batch -> number (updated count) */
+    updateRange(entities: T[]): Observable<number> {
+        return this.http
+            .put<number>(`${this.endpoint}/batch`, entities, { headers: this.jsonHeaders })
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** DELETE /api/{controller}/{id} */
+    delete(id: string): Observable<void> {
+        return this.http
+            .delete<void>(`${this.endpoint}/${id}`)
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** DELETE /api/{controller}/batch -> text summary */
+    deleteRange(ids: string[]): Observable<TextResponse> {
+        // API returns a plain text message; map it into a TextResponse for convenience
+        return this.http
+            .delete(`${this.endpoint}/batch`, {
+                body: ids,
+                headers: this.jsonHeaders
+            })
+            .pipe(
+                map((response: any) => ({ message: response || 'Batch delete completed' })),
+                catchError(err => this.handleError(err))
+            );
+    }
+
+
+    /** GET /api/{controller}/{id}/exists -> boolean */
+    exists(id: string): Observable<boolean> {
+        return this.http
+            .get<boolean>(`${this.endpoint}/${id}/exists`)
+            .pipe(catchError(err => this.handleError(err)));
+    }
+
+
+    /** GET /api/{controller}/count -> number */
+    count(): Observable<number> {
+        return this.http
+            .get<number>(`${this.endpoint}/count`)
+            .pipe(catchError(err => this.handleError(err)));
+    }
+}