Merge pull request #895 from girder/can-read-list

Add canReadList function to show what sources could be used.

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Features
 - Add a tifffile tile source ([885](../../pull/885))
+- Added a canReadList method to large_image to show which source can be used ([895](../../pull/895))
 
 ### Improvements
 - Pass options to the annotationLayer mode ([881](../../pull/881))

large_image/__init__.py

@@ -15,7 +15,7 @@
 #############################################################################
 
 from . import tilesource  # noqa
-from .tilesource import canRead, getTileSource, new, open  # noqa
+from .tilesource import canRead, canReadList, getTileSource, new, open  # noqa
 
 try:
     from importlib.metadata import PackageNotFoundError

large_image/tilesource/__init__.py

@@ -66,17 +66,16 @@ def loadTileSources(entryPointName='large_image.source', sourceDict=AvailableTil
                 'Failed to loaded tile source %s' % entryPoint.name)
 
 
-def getSourceNameFromDict(availableSources, pathOrUri, *args, **kwargs):
+def getSortedSourceList(availableSources, pathOrUri, *args, **kwargs):
     """
-    Get a tile source based on a ordered dictionary of known sources and a path
-    name or URI.  Additional parameters are passed to the tile source and can
-    be used for properties such as encoding.
+    Get an ordered list of sources where earlier sources are more likely to
+    work for a specified path or uri.
 
     :param availableSources: an ordered dictionary of sources to try.
     :param pathOrUri: either a file path or a fixed source via
         large_image://<source>.
-    :returns: the name of a tile source that can read the input, or None if
-        there is no such source.
+    :returns: a list of (clash, priority, sourcename) for sources where
+        sourcename is a key in availableSources.
     """
     uriWithoutProtocol = str(pathOrUri).split('://', 1)[-1]
     isLargeImageUri = str(pathOrUri).startswith('large_image://')
@@ -99,6 +98,22 @@ def getSourceNameFromDict(availableSources, pathOrUri, *args, **kwargs):
             getattr(availableSources[sourceName], k, False) != v
             for k, v in properties.items())
         sourceList.append((propertiesClash, priority, sourceName))
+    return sourceList
+
+
+def getSourceNameFromDict(availableSources, pathOrUri, *args, **kwargs):
+    """
+    Get a tile source based on a ordered dictionary of known sources and a path
+    name or URI.  Additional parameters are passed to the tile source and can
+    be used for properties such as encoding.
+
+    :param availableSources: an ordered dictionary of sources to try.
+    :param pathOrUri: either a file path or a fixed source via
+        large_image://<source>.
+    :returns: the name of a tile source that can read the input, or None if
+        there is no such source.
+    """
+    sourceList = getSortedSourceList(availableSources, pathOrUri, *args, **kwargs)
     for _clash, _priority, sourceName in sorted(sourceList):
         if availableSources[sourceName].canRead(pathOrUri, *args, **kwargs):
             return sourceName
@@ -161,6 +176,21 @@ def canRead(*args, **kwargs):
     return False
 
 
+def canReadList(*args, **kwargs):
+    """
+    Check if large_image can read a path or uri via each source.
+
+    :returns: A list of tuples of (source name, canRead).
+    """
+    if not len(AvailableTileSources):
+        loadTileSources()
+    sourceList = getSortedSourceList(AvailableTileSources, *args, **kwargs)
+    result = []
+    for _clash, _priority, sourceName in sorted(sourceList):
+        result.append((sourceName, AvailableTileSources[sourceName].canRead(*args, **kwargs)))
+    return result
+
+
 def new(*args, **kwargs):
     """
     Create a new image.

test/test_source_base.py

@@ -499,3 +499,9 @@ def testGetTileFramesQuadInfo(options, lensrc, lenquads, frame10, src0, srclast,
         crop10 = results['quads'][10]['crop']
         for key, value in quads10.items():
             assert crop10[key] == value
+
+
+def testCanReadList():
+    imagePath = datastore.fetch('sample_image.ptif')
+    assert len(large_image.canReadList(imagePath)) > 1
+    assert any(canRead for source, canRead in large_image.canReadList(imagePath))