- add DatasetApiService wit HttpService

- Interfaces for stations and phenomena

src/app/services/dataset-api.service.ts

@@ -0,0 +1,63 @@
+// https://github.com/52North/helgoland-toolbox/blob/develop/libs/core/src/lib/dataset-api/dataset-impl-api-interface.service.ts
+// https://github.com/52North/helgoland-toolbox/blob/495f75cadcc3e7232206db1cd5dd8bbf3a172c4b/libs/core/src/lib/abstract-services/api-interface.ts#L6
+// https://github.com/52North/helgoland-toolbox/blob/495f75cadcc3e7232206db1cd5dd8bbf3a172c4b/libs/core/src/lib/api-communication/connectors/dataset-api-v3-connector/api-v3-interface.ts#L321
+import { Injectable } from '@angular/core';
+import { HttpClient, HttpHeaders  } from '@angular/common/http';
+import { Observable } from 'rxjs';
+import { Phenomenon } from '../../shared/models/phenomenon';
+import { Station } from '../../shared/models/station';
+
+import { HttpService } from './http.service';
+import { HttpRequestOptions } from '../../shared/models/http-requests';
+import { HttpParams } from '@angular/common/http';
+
+
+// @Injectable({
+//   providedIn: 'root'
+// })
+
+@Injectable()
+export class DatasetApiService {
+
+    // constructor() { }
+    constructor(
+        private httpClient: HttpClient,
+        protected httpService: HttpService,) {
+    }
+
+    public getPhenomena(apiUrl: string, params?, options?) {
+        const url = this.createRequestUrl(apiUrl, 'phenomena');        
+        return this.requestApi<Phenomenon[]>(url, params, options);
+    }
+
+    public getStations(apiUrl: string, params?, options?: HttpRequestOptions): Observable<Station[]> {
+        const url = this.createRequestUrl(apiUrl, 'features');
+        return this.requestApi<Station[]>(url, params, options);
+    }
+
+
+    protected createRequestUrl(apiUrl: string, endpoint: string, id?: string) {
+        // TODO Check whether apiUrl ends with slash
+        let requestUrl = apiUrl + endpoint;
+        if (id) { requestUrl += '/' + id; }
+        return requestUrl;
+    }
+
+    protected requestApi<T>(
+        url: string, params: HttpParams = new HttpParams(), options: HttpRequestOptions = {}
+    ): Observable<T> {
+        return this.httpService.client(options).get<T>(url,
+            {
+                params,
+                headers: this.createBasicAuthHeader(options.basicAuthToken)
+            }
+        );
+    }
+
+    protected createBasicAuthHeader(token: string): HttpHeaders {
+        const headers = new HttpHeaders();
+        if (token) { return headers.set('Authorization', token); }
+        return headers;
+    }
+
+}