DEV: Implement os.walk analog for ContentsManagers.

IPython/html/services/contents/manager.py

@@ -30,6 +30,21 b' from IPython.utils.py3compat import string_types'
 copy_pat = re.compile(r'\-Copy\d*\.')
 
 
+def _separate_dirs_files(models):
+    """
+    Split an iterable of models into a list of file paths and a list of
+    directory paths.
+    """
+    dirs = []
+    files = []
+    for model in models:
+        if model['type'] == 'directory':
+            dirs.append(model['path'])
+        else:
+            files.append(model['path'])
+    return dirs, files
+
+
 class CheckpointManager(LoggingConfigurable):
     """
     Base class for managing checkpoints for a ContentsManager.
@@ -499,6 +514,31 b' class ContentsManager(LoggingConfigurable):'
         """Should this file/directory name be displayed in a listing?"""
         return not any(fnmatch(name, glob) for glob in self.hide_globs)
 
+    def walk(self):
+        """
+        Like os.walk, but written in terms of the ContentsAPI.
+
+        Returns a generator of tuples of the form:
+        (directory name, [subdirectories], [files in directory])
+        """
+        return self._walk([''])
+
+    def _walk(self, dirs):
+        """
+        Recursive helper for walk.
+        """
+        for directory in dirs:
+            children = self.get(
+                directory,
+                content=True,
+                type='directory',
+            )['content']
+            dirs, files = map(sorted, _separate_dirs_files(children))
+            yield (directory, dirs, files)
+            if dirs:
+                for entry in self._walk(dirs):
+                    yield(entry)
+
     # Part 3: Checkpoints API
     def create_checkpoint(self, path):
         """Create a checkpoint."""

IPython/html/services/contents/tests/test_contents_api.py

@@ -614,3 +614,82 b' class APITest(NotebookTestBase):'
         with TemporaryDirectory() as td:
             with self.patch_cp_root(td):
                 self.test_file_checkpoints()
+
+    def test_walk(self):
+        """
+        Test ContentsManager.walk.
+        """
+        results = list(self.notebook.contents_manager.walk())
+        expected = [
+            (
+                '',
+                [
+                    'Directory with spaces in',
+                    'foo',
+                    'ordering',
+                    u'unicodé',
+                    u'å b',
+                ],
+                ['inroot.blob', 'inroot.ipynb', 'inroot.txt'],
+            ),
+            (
+                'Directory with spaces in',
+                [],
+                ['inspace.blob', 'inspace.ipynb', 'inspace.txt'],
+            ),
+            (
+                'foo',
+                ['bar'],
+                [
+                    'a.blob', 'a.ipynb', 'a.txt',
+                    'b.blob', 'b.ipynb', 'b.txt',
+                    'name with spaces.blob',
+                    'name with spaces.ipynb',
+                    'name with spaces.txt',
+                    u'unicodé.blob', u'unicodé.ipynb', u'unicodé.txt'
+                ]
+            ),
+            (
+                'foo/bar',
+                [],
+                ['baz.blob', 'baz.ipynb', 'baz.txt'],
+            ),
+            (
+                'ordering',
+                [],
+                [
+                    'A.blob', 'A.ipynb', 'A.txt',
+                    'C.blob', 'C.ipynb', 'C.txt',
+                    'b.blob', 'b.ipynb', 'b.txt',
+                ],
+            ),
+            (
+                u'unicodé',
+                [],
+                ['innonascii.blob', 'innonascii.ipynb', 'innonascii.txt'],
+            ),
+            (
+                u'å b',
+                [],
+                [u'ç d.blob', u'ç d.ipynb', u'ç d.txt'],
+            ),
+        ]
+
+        for idx, (dname, subdirs, files) in enumerate(expected):
+            result_dname, result_subdirs, result_files = results[idx]
+            if dname == '':
+                sep = ''
+            else:
+                sep = '/'
+            self.assertEqual(
+                dname,
+                result_dname,
+            )
+            self.assertEqual(
+                [sep.join([dname, sub]) for sub in subdirs],
+                result_subdirs,
+            )
+            self.assertEqual(
+                [sep.join([dname, fname]) for fname in files],
+                result_files,
+            )