Added upload method to generic service

src/lib/services/generic.service.ts

@@ -1,4 +1,4 @@
-import { HttpClient, HttpParams } from '@angular/common/http';
+import { HttpClient, HttpEvent, HttpParams } from '@angular/common/http';
 import { Injector } from '@angular/core';
 import { Observable } from 'rxjs';
 import { CustomHttpUrlEncodingCodec, List, RequiredParam, Validate } from '../utils';
@@ -40,7 +40,11 @@ export abstract class GenericService<I> {
     }
 
     @Validate()
-    delete(@RequiredParam() body: unknown, modelPath = this._defaultModelPath, queryParams?: List<QueryParam>): Observable<unknown> {
+    delete(
+        @RequiredParam() body: unknown,
+        modelPath = this._defaultModelPath,
+        queryParams?: List<QueryParam>,
+    ): Observable<unknown> {
         let path = `/${encodeURI(modelPath)}`;
 
         if (typeof body === 'string') {
@@ -55,6 +59,24 @@ export abstract class GenericService<I> {
         });
     }
 
+    @Validate()
+    upload<R = I>(data?: Blob, modelPath = this._defaultModelPath): Observable<HttpEvent<R>> {
+        const formParams = new FormData();
+
+        if (data !== undefined) {
+            formParams.append('file', data);
+        }
+
+        // TODO: Fix getHeaders()?
+        const headers = HeadersConfiguration.getHeaders().delete('content-type');
+
+        return this._http.post<R>(`/${encodeURI(modelPath)}`, formParams, {
+            headers,
+            observe: 'events',
+            reportProgress: true,
+        });
+    }
+
     @Validate()
     protected _post<R = I>(
         @RequiredParam() body: unknown,