OWSave: Implement get_filters() for dynamic retrieval of available filters

Author: janezd

Orange/data/io.py

@@ -395,6 +395,8 @@ def write_file(cls, filename, data):
     # the sort order in file open/save combo boxes. Lower is better.
     PRIORITY = 10000
     OPTIONAL_TYPE_ANNOTATIONS = False
+    SUPPORT_COMPRESSED = False
+    SUPPORT_SPARSE_DATA = False
 
     def __init__(self, filename):
         """

Orange/widgets/data/owsave.py

@@ -1,8 +1,8 @@
 import os.path
 
 from Orange.data.table import Table
-from Orange.data.io import TabReader, CSVReader, PickleReader, ExcelReader, \
-    XlsReader
+from Orange.data.io import \
+    TabReader, CSVReader, PickleReader, ExcelReader, XlsReader, FileFormat
 from Orange.widgets import gui, widget
 from Orange.widgets.widget import Input
 from Orange.widgets.settings import Setting
@@ -22,14 +22,6 @@ class OWSave(OWSaveBase):
 
     settings_version = 2
 
-    writers = [TabReader, CSVReader, PickleReader, ExcelReader, XlsReader]
-    filters = {
-        **{f"{w.DESCRIPTION} (*{w.EXTENSIONS[0]})": w
-           for w in writers},
-        **{f"Compressed {w.DESCRIPTION} (*{w.EXTENSIONS[0]}.gz)": w
-           for w in writers if w.SUPPORT_COMPRESSED}
-    }
-
     class Inputs:
         data = Input("Data", Table)
 
@@ -38,6 +30,8 @@ class Error(OWSaveBase.Error):
 
     add_type_annotations = Setting(True)
 
+    builtin_order = [TabReader, CSVReader, PickleReader, ExcelReader, XlsReader]
+
     def __init__(self):
         super().__init__(2)
 
@@ -53,6 +47,21 @@ def __init__(self):
         self.grid.setRowMinimumHeight(1, 8)
         self.adjustSize()
 
+    @classmethod
+    def get_filters(cls):
+        writers = [format for format in FileFormat.formats
+                   if getattr(format, 'write_file', None)
+                   and getattr(format, "EXTENSIONS", None)]
+        writers.sort(key=lambda writer: cls.builtin_order.index(writer)
+                     if writer in cls.builtin_order else 99)
+
+        return {
+            **{f"{w.DESCRIPTION} (*{w.EXTENSIONS[0]})": w
+               for w in writers},
+            **{f"Compressed {w.DESCRIPTION} (*{w.EXTENSIONS[0]}.gz)": w
+               for w in writers if w.SUPPORT_COMPRESSED}
+        }
+
     @Inputs.data
     def dataset(self, data):
         self.data = data
@@ -137,7 +146,7 @@ def default_valid_filter(self):
         valid = self.valid_filters()
         if self.data is None or not self.data.is_sparse() \
                 or (self.filter in valid
-                    and valid[self.filter].SUPPORT_SPARSE_DATA):
+                        and valid[self.filter].SUPPORT_SPARSE_DATA):
             return self.filter
         return next(iter(valid))
 

Orange/widgets/data/tests/test_owsave.py

@@ -8,7 +8,7 @@
 from AnyQt.QtWidgets import QFileDialog
 
 from Orange.data import Table
-from Orange.data.io import TabReader, PickleReader, ExcelReader
+from Orange.data.io import TabReader, PickleReader, ExcelReader, FileFormat
 from Orange.tests import named_file
 from Orange.widgets.data.owsave import OWSave, OWSaveBase
 from Orange.widgets.utils.save.tests.test_owsavebase import \
@@ -23,6 +23,15 @@ def _w(s):  # pylint: disable=invalid-name
     return s.replace("/", os.sep)
 
 
+class MockFormat(FileFormat):
+    EXTENSIONS = ('.mock',)
+    DESCRIPTION = "Mock file format"
+
+    @staticmethod
+    def write_file(filename, data):
+        pass
+
+
 class OWSaveTestBase(WidgetTest, SaveWidgetsTestBaseMixin):
     def setUp(self):
         with open_widget_classes():
@@ -285,7 +294,12 @@ def test_valid_default_filter(self):
         widget.data.X = sp.csr_matrix(widget.data.X)
         self.assertTrue(
             widget.get_filters()[widget.default_valid_filter()]
-                .SUPPORT_SPARSE_DATA)
+            .SUPPORT_SPARSE_DATA)
+
+    def test_add_on_writers(self):
+        # test adding file formats after registering the widget
+        self.assertIn(MockFormat, self.widget.valid_filters().values())
+        # this test doesn't call it - test_save_uncompressed does
 
     def test_send_report(self):
         widget = self.widget
@@ -387,12 +401,14 @@ def test_save_uncompressed(self):
 
                 self.send_signal(widget.Inputs.data, self.iris)
                 widget.save_file_as()
-                self.assertEqual(len(Table(filename)), 150)
+                if hasattr(writer, "read"):
+                    self.assertEqual(len(Table(filename)), 150)
 
                 if writer.SUPPORT_SPARSE_DATA:
                     self.send_signal(widget.Inputs.data, spiris)
                     widget.save_file()
-                    self.assertEqual(len(Table(filename)), 150)
+                    if hasattr(writer, "read"):
+                        self.assertEqual(len(Table(filename)), 150)
 
 
 @unittest.skipUnless(sys.platform == "linux", "Tests for dialog on Linux")