From a27a0c8b9c46472e26c9e7a2535a4088617140d3 Mon Sep 17 00:00:00 2001
From: Lorenz Hilpert <l.hilpert@paragon-data.de>
Date: Tue, 31 May 2022 15:55:04 +0200
Subject: [PATCH] Zxing ask for camera permission

---
 .../lib/zxing-modal/zxing-modal.component.ts  | 88 ++++++++++++-------
 1 file changed, 54 insertions(+), 34 deletions(-)

diff --git a/apps/adapter/scan/src/lib/zxing-modal/zxing-modal.component.ts b/apps/adapter/scan/src/lib/zxing-modal/zxing-modal.component.ts
index 29fe38252..18bc3a18a 100644
--- a/apps/adapter/scan/src/lib/zxing-modal/zxing-modal.component.ts
+++ b/apps/adapter/scan/src/lib/zxing-modal/zxing-modal.component.ts
@@ -1,5 +1,5 @@
 import { Component, ChangeDetectionStrategy, ViewChild, ElementRef, AfterViewInit, NgZone, Inject, OnDestroy, OnInit } from '@angular/core';
-import { UiModalRef, UiModalService } from '@ui/modal';
+import { UiMessageModalComponent, UiModalRef, UiModalService } from '@ui/modal';
 import { BarcodeFormat, DecodeHintType, BrowserMultiFormatReader } from '@zxing/library';
 import { BehaviorSubject, from, ReplaySubject, Subject } from 'rxjs';
 import { filter, takeUntil, tap } from 'rxjs/operators';
@@ -27,45 +27,65 @@ export class ZxingModalComponent implements OnInit, OnDestroy {
 
   constructor(private _modalRef: UiModalRef, private readonly _zone: NgZone, private readonly _modal: UiModalService) {}
 
-  ngOnInit(): void {
-    const hints = new Map<DecodeHintType, any>();
+  async ngOnInit() {
+    try {
+      const mediaStream: MediaStream = await navigator.mediaDevices.getUserMedia({ video: true, audio: false });
+      mediaStream.getVideoTracks().forEach((track) => track.stop());
 
-    const formats = [
-      BarcodeFormat.EAN_8,
-      BarcodeFormat.EAN_13,
-      BarcodeFormat.UPC_A,
-      BarcodeFormat.UPC_E,
-      BarcodeFormat.CODE_128,
-      BarcodeFormat.CODE_39,
-      BarcodeFormat.CODE_93,
-      BarcodeFormat.ITF,
-      BarcodeFormat.QR_CODE,
-    ];
+      const hints = new Map<DecodeHintType, any>();
 
-    hints.set(DecodeHintType.POSSIBLE_FORMATS, formats);
+      const formats = [
+        BarcodeFormat.EAN_8,
+        BarcodeFormat.EAN_13,
+        BarcodeFormat.UPC_A,
+        BarcodeFormat.UPC_E,
+        BarcodeFormat.CODE_128,
+        BarcodeFormat.CODE_39,
+        BarcodeFormat.CODE_93,
+        BarcodeFormat.ITF,
+        BarcodeFormat.QR_CODE,
+      ];
 
-    this._reader = new BrowserMultiFormatReader(hints, 1000);
+      hints.set(DecodeHintType.POSSIBLE_FORMATS, formats);
 
-    from(this._reader.listVideoInputDevices()).subscribe((devices) => {
-      this.devices$.next(devices);
-      this.selectedDevice$.next(devices[0].deviceId);
-    });
+      this._reader = new BrowserMultiFormatReader(hints, 1000);
 
-    this.selectedDevice$
-      .pipe(
-        takeUntil(this._onDestroy$),
-        filter((v) => !!v),
-        tap(() => {
-          this._reader?.reset();
-        })
-      )
-      .subscribe((device) => {
-        this._reader.decodeFromVideoDevice(device, this.scanContainer.nativeElement, (result) => {
-          if (result) {
-            this._modalRef.close(result.getText());
-          }
-        });
+      from(this._reader.listVideoInputDevices()).subscribe((devices) => {
+        this.devices$.next(devices);
+        this.selectedDevice$.next(devices[0].deviceId);
       });
+
+      this.selectedDevice$
+        .pipe(
+          takeUntil(this._onDestroy$),
+          filter((v) => !!v),
+          tap(() => {
+            this._reader?.reset();
+          })
+        )
+        .subscribe((device) => {
+          this._reader.decodeFromVideoDevice(device, this.scanContainer.nativeElement, (result) => {
+            if (result) {
+              this._modalRef.close(result.getText());
+            }
+          });
+        });
+    } catch (error) {
+      this.cancel();
+      this._modal
+        .open({
+          content: UiMessageModalComponent,
+          data: {
+            message: `
+    Scanner kann nicht aktiviert werden.
+    Bitte stellen Sie sicher, dass der zugriff auf die Kamera erlaubt ist.
+  `,
+          },
+        })
+        .afterClosed$.subscribe(() => {
+          this.cancel();
+        });
+    }
   }
 
   cancel() {