Don't scan as many files when checking for multi file dicom

CHANGELOG.md

@@ -5,7 +5,7 @@
 ### Improvements
 - Read config values from the environment variables ([#1422](../../pull/1422))
 - Optimizing when reading arrays rather than images from tiff files ([#1423](../../pull/1423))
-- Better filter DICOM adjacent files to ensure they share series instance IDs ([#1424](../../pull/1424), [#1436](../../pull/1436))
+- Better filter DICOM adjacent files to ensure they share series instance IDs ([#1424](../../pull/1424), [#1436](../../pull/1436), [#1442](../../pull/1442))
 - Optimizing small getRegion calls and some tiff tile fetches ([#1427](../../pull/1427))
 - Started adding python types to the core library ([#1432](../../pull/1432), [#1433](../../pull/1433), [#1437](../../pull/1437), [#1438](../../pull/1438), [#1439](../../pull/1439))
 - Use parallelism in computing tile frames ([#1434](../../pull/1434))

sources/dicom/large_image_source_dicom/__init__.py

@@ -53,6 +53,7 @@ def _lazyImportPydicom():
 
     if pydicom is None:
         import pydicom
+    return pydicom
 
 
 def dicom_to_dict(ds, base=None):
@@ -138,6 +139,12 @@ def __init__(self, path, **kwargs):
             if not os.path.isfile(path):
                 raise TileSourceFileNotFoundError(path) from None
             root = os.path.dirname(path) or '.'
+            try:
+                _lazyImportPydicom()
+                pydicom.filereader.dcmread(path, stop_before_pixels=True)
+            except Exception as exc:
+                msg = f'File cannot be opened via dicom tile source ({exc}).'
+                raise TileSourceError(msg)
             self._largeImagePath = [
                 os.path.join(root, entry) for entry in os.listdir(root)
                 if os.path.isfile(os.path.join(root, entry)) and

sources/dicom/large_image_source_dicom/girder_source.py

@@ -5,8 +5,9 @@
 from girder.models.folder import Folder
 from girder.models.item import Item
 from girder.utility import assetstore_utilities
+from large_image.exceptions import TileSourceError
 
-from . import DICOMFileTileSource
+from . import DICOMFileTileSource, _lazyImportPydicom
 from .assetstore import DICOMWEB_META_KEY
 
 
@@ -46,8 +47,13 @@
         filelist = [
             File().getLocalFilePath(file) for file in Item().childFiles(self.item)
             if self._pathMightBeDicom(file['name'])]
-        if len(filelist) > 1:
+        if len(filelist) != 1:
             return filelist
+        try:
+            _lazyImportPydicom().filereader.dcmread(filelist[0], stop_before_pixels=True)
+        except Exception as exc:
+            msg = f'File cannot be opened via dicom tile source ({exc}).'
+            raise TileSourceError(msg)
         filelist = []
         folder = Folder().load(self.item['folderId'], force=True)
         for item in Folder().childItems(folder):