Allow specifying which sources are checked with canReadList

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Improvements
 - Show a loading spinner on the image display in geojs in girder ([#1559](../../pull/1559))
 - Better handle images that are composed of a folder and an item ([#1561](../../pull/1561))
+- Allow specifying which sources are checked with canReadList ([#1562](../../pull/1562))
 
 ### Bug Fixes
 - Fix a compositing error in transformed multi source images ([#1560](../../pull/1560))

large_image/tilesource/__init__.py

@@ -208,6 +208,7 @@ def canRead(*args, **kwargs) -> bool:
 
 def canReadList(
         pathOrUri: Union[str, PosixPath], mimeType: Optional[str] = None,
+        availableSources: Optional[Dict[str, Type[FileTileSource]]] = None,
         *args, **kwargs) -> List[Tuple[str, bool]]:
     """
     Check if large_image can read a path or uri via each source.
@@ -218,16 +219,18 @@ def canReadList(
     :param pathOrUri: either a file path or a fixed source via
         large_image://<source>.
     :param mimeType: the mimetype of the file, if known.
+    :param availableSources: an ordered dictionary of sources to try.  If None,
+        use the primary list of sources.
     :returns: A list of tuples of (source name, canRead).
     """
-    if not len(AvailableTileSources):
+    if availableSources is None and not len(AvailableTileSources):
         loadTileSources()
     sourceList = getSortedSourceList(
-        AvailableTileSources, pathOrUri, mimeType, *args, **kwargs)
+        availableSources or AvailableTileSources, pathOrUri, mimeType, *args, **kwargs)
     result = []
     for entry in sorted(sourceList):
         sourceName = entry[-1]
-        result.append((sourceName, AvailableTileSources[sourceName].canRead(
+        result.append((sourceName, (availableSources or AvailableTileSources)[sourceName].canRead(
             pathOrUri, *args, **kwargs)))
     return result
 

test/lisource_compare.py

@@ -139,7 +139,11 @@ def source_compare(sourcePath, opts):  # noqa
     else:
         sys.stdout.write('%s\n' % sourcePath)
     sys.stdout.flush()
-    canread = large_image.canReadList(sourcePath)
+    sublist = {
+        k: v for k, v in large_image.tilesource.AvailableTileSources.items()
+        if (getattr(opts, 'skipsource', None) is None or k not in opts.skipsource) and
+           (getattr(opts, 'usesource', None) is None or k in opts.usesource)}
+    canread = large_image.canReadList(sourcePath, availableSources=sublist)
     large_image.cache_util.cachesClear()
     slen = max([len(source) for source, _ in canread] + [10])
     sys.stdout.write('Source' + ' ' * (slen - 6))