Handle report error on missing svg data (#12514) (#12517)

* Handle report error on missing svg data

* Add regression tests

(cherry picked from commit 76a0005b61)

Co-authored-by: Oliver <oliver.henry.walters@gmail.com>

src/backend/InvenTree/report/templatetags/report.py

@@ -451,8 +451,13 @@ def uploaded_image(
 
 
 @register.simple_tag()
-def encode_svg_image(filename: str) -> str:
+def encode_svg_image(filename: str, raise_error: bool = False) -> str:
-    """Return a base64-encoded svg image data string."""
+    """Return a base64-encoded svg image data string.
+
+    Arguments:
+        filename: The filename of the svg image relative to the media root directory
+        raise_error: If True, raise an error if the file cannot be found (default = False)
+    """
     if type(filename) is SafeString:
         # Prepend an empty string to enforce 'stringiness'
         filename = '' + filename
@@ -465,7 +470,12 @@ def encode_svg_image(filename: str) -> str:
 
     # Read out the file contents
     # Note: This will check if the file exists, and raise an error if it does not
-    data = get_media_file_contents(filename)
+    data = get_media_file_contents(filename, raise_error=raise_error)
+
+    # If the file is empty, return an empty string
+    # Note that if raise_error is True, the above function will raise a FileNotFoundError if the file does not exist
+    if not data:
+        return ''
 
     # Return the base64-encoded data
     return 'data:image/svg+xml;charset=utf-8;base64,' + base64.b64encode(data).decode(

src/backend/InvenTree/report/test_tags.py

@@ -524,6 +524,17 @@ class ReportTagTest(PartImageTestMixin, InvenTreeTestCase):
             svg,
         )
 
+        # Test with a missing SVG file - default behavior is to return an empty string
+        missing_path = 'missing_svg_image_123abc.svg'
+        self.assertEqual(report_tags.encode_svg_image(missing_path), '')
+        self.assertEqual(
+            report_tags.encode_svg_image(missing_path, raise_error=False), ''
+        )
+
+        # Test with a missing SVG file, with raise_error=True
+        with self.assertRaises(FileNotFoundError):
+            report_tags.encode_svg_image(missing_path, raise_error=True)
+
     def test_part_parameter(self):
         """Test the part_parameter template tag."""
         # Test with a valid part