- add DatasetApiService wit HttpService

- Interfaces for stations and phenomena

src/app/services/http.service.ts

@@ -0,0 +1,45 @@
+// https://github.com/52North/helgoland-toolbox/blob/495f75cadcc3e7232206db1cd5dd8bbf3a172c4b/libs/core/src/lib/dataset-api/http.service.ts#L37
+import { Injectable } from '@angular/core';
+import { HttpClient, HttpEvent, HttpHandler, HttpRequest } from '@angular/common/http';
+import { Inject, InjectionToken, Optional } from '@angular/core';
+import { Observable } from 'rxjs';
+
+import { HttpRequestOptions } from '../../shared/models/http-requests';
+
+export const HTTP_SERVICE_INTERCEPTORS = new InjectionToken<HttpServiceInterceptor>('HTTP_SERVICE_INTERCEPTORS');
+
+export interface HttpServiceHandler {
+    handle(req: HttpRequest<any>, options: Partial<HttpRequestOptions>): Observable<HttpEvent<any>>;
+}
+
+export interface HttpServiceInterceptor {
+    intercept(req: HttpRequest<any>, options: Partial<HttpRequestOptions>, next: HttpServiceHandler): Observable<HttpEvent<any>>;
+}
+
+
+@Injectable()
+export class HttpService {
+
+    private handler: HttpServiceHandler;
+
+    constructor(
+        protected httpHandler: HttpHandler,
+        @Optional() @Inject(HTTP_SERVICE_INTERCEPTORS) interceptors: HttpServiceInterceptor[] | null
+    ) {
+        let handler: HttpServiceHandler = {
+            handle: (req, options) => httpHandler.handle(req)
+        };
+        if (interceptors) {
+            handler = interceptors.reduceRight((next, interceptor) => ({
+                handle: (req, options) => interceptor.intercept(req, options, next)
+            }), handler);
+        }
+        this.handler = handler;
+    }
+
+    public client(options: HttpRequestOptions = {}): HttpClient {
+        return new HttpClient({
+            handle: (req) => this.handler.handle(req, options)
+        });
+    }
+}