configuration option for type of PDF viewer fixes #337

src-ui/src/app/pipes/safe.pipe.spec.ts

@@ -0,0 +1,8 @@
+import { SafePipe } from './safe.pipe';
+
+describe('SafePipe', () => {
+  it('create an instance', () => {
+    const pipe = new SafePipe();
+    expect(pipe).toBeTruthy();
+  });
+});

src-ui/src/app/pipes/safe.pipe.ts

@@ -0,0 +1,19 @@
+import { Pipe, PipeTransform } from '@angular/core';
+import { DomSanitizer } from '@angular/platform-browser';
+
+@Pipe({
+  name: 'safe'
+})
+export class SafePipe implements PipeTransform {
+
+  constructor(private sanitizer: DomSanitizer) { }
+
+  transform(url) {
+    if (url == null) {
+      return this.sanitizer.bypassSecurityTrustResourceUrl("")
+    } else {
+      return this.sanitizer.bypassSecurityTrustResourceUrl(url);
+    }
+  }
+
+}