feat: add new Numbas Feature

Added new Numbas Service to the frontend as part of Integration

Changed by: Daniel Maddern

src/app/api/services/numbas.service.ts

@@ -0,0 +1,66 @@
+import { Injectable } from '@angular/core';
+import { HttpClient, HttpErrorResponse, HttpHeaders } from '@angular/common/http';
+import { Observable, throwError } from 'rxjs';
+import { catchError, map, retry } from 'rxjs/operators';
+
+@Injectable({
+  providedIn: 'root'
+})
+export class NumbasService {
+  private readonly API_URL = 'http://localhost:3000/api/numbas_api';
+
+  constructor(private http: HttpClient) {}
+
+  fetchResource(unitId: string, taskId: string, resourcePath: string): Observable<any> {
+    const resourceUrl = `${this.API_URL}/${unitId}/${taskId}/${resourcePath}`;
+    const resourceMimeType = this.getMimeType(resourcePath);
+
+    return this.http.get(resourceUrl, { responseType: 'blob' }).pipe(
+      retry(3),  // Retrying up to 3 times before failing
+      map((blob) => new Blob([blob], { type: resourceMimeType })),
+      catchError((error: HttpErrorResponse) => {
+        console.error('Error fetching Numbas resource:', error);
+        return throwError('Error fetching Numbas resource.');
+      })
+    );
+  }
+
+  getMimeType(resourcePath: string): string {
+    const extension = resourcePath.split('.').pop()?.toLowerCase();
+    const mimeTypeMap: { [key: string]: string } = {
+      'html': 'text/html',
+      'css': 'text/css',
+      'js': 'application/javascript',
+      'json': 'application/json',
+      'png': 'image/png',
+      'jpg': 'image/jpeg',
+      'gif': 'image/gif',
+      'svg': 'image/svg+xml'
+    };
+
+    return mimeTypeMap[extension || ''] || 'text/plain';
+  }
+  uploadTest(unitId: string, taskId: string, file: File): Observable<any> {
+    const uploadUrl = `${this.API_URL}/uploadNumbasTest`;
+    const formData = new FormData();
+
+    formData.append('file', file);
+    formData.append('unit_code', unitId);
+    formData.append('task_definition_id', taskId);
+
+    const httpOptions = {
+      headers: new HttpHeaders({
+        // You might need to set some headers here depending on your backend requirements
+        'Accept': 'application/json'
+      })
+    };
+
+    return this.http.post(uploadUrl, formData, httpOptions).pipe(
+      retry(3),
+      catchError((error: HttpErrorResponse) => {
+        console.error('Error uploading Numbas test:', error);
+        return throwError('Error uploading Numbas test.');
+      })
+    );
+  }
+}