Adds methods to get workflow specs and files

src/app/_services/api.service.ts

@@ -1,7 +1,10 @@
-import {HttpClient} from '@angular/common/http';
+import {HttpClient, HttpParams} from '@angular/common/http';
 import {Injectable} from '@angular/core';
 import {Observable, throwError} from 'rxjs';
 import {catchError} from 'rxjs/operators';
+import {environment} from '../../environments/environment';
+import {WorkflowSpec} from 'sartography-workflow-lib';
+import {FileMeta} from 'sartography-workflow-lib';
 
 export interface ApiError {
   code: string;
@@ -13,9 +16,36 @@ export interface ApiError {
 })
 export class ApiService {
 
+  apiUrl: string = environment.api;
+
   constructor(private httpClient: HttpClient) {
   }
 
+  listWorkflowSpecifications(): Observable<WorkflowSpec[]> {
+    const url = this.apiUrl + '/workflow-specification';
+
+    return this.httpClient
+      .get<WorkflowSpec[]>(url)
+      .pipe(catchError(this._handleError));
+  }
+
+  listBpmnFiles(specId: string): Observable<FileMeta[]> {
+    const url = this.apiUrl + '/file';
+    const params = new HttpParams().set('spec_id', specId);
+
+    return this.httpClient
+      .get<FileMeta[]>(url, {params: params})
+      .pipe(catchError(this._handleError));
+  }
+
+  getFileData(fileId: number): Observable<Blob> {
+    const url = this.apiUrl + '/file/' + fileId + '/data';
+
+    return this.httpClient
+      .get(url, {responseType: 'blob'})
+      .pipe(catchError(this._handleError));
+  }
+
   getBpmnXml(url: string): Observable<string> {
     return this.httpClient
       .get(url, {responseType: 'text'})