Added FileSelector widget

examples/reference/widgets/CrossSelector.ipynb

@@ -25,13 +25,16 @@
     "\n",
     "##### Core\n",
     "\n",
+    "* **``definition_order``** (boolean, default=True): Whether to preserve definition order after filtering. Disable to allow the order of selection to define the order of the selected list.\n",
+    "* **``filter_fn``** (function): The filter function applied when querying using the text fields, defaults to re.search. Function is two arguments, the query or pattern and the item label.\n",
     "* **``options``** (list or dict): List or dictionary of available options\n",
     "* **``value``** (boolean): Currently selected options\n",
     "\n",
     "##### Display\n",
     "\n",
     "* **``disabled``** (boolean): Whether the widget is editable\n",
     "* **``name``** (str): The title of the widget\n",
+    "* **``size``** (int): The number of items to show in the selected and unselected lists\n",
     "\n",
     "___"
    ]

examples/reference/widgets/FileSelector.ipynb

@@ -0,0 +1,105 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import panel as pn\n",
+    "pn.extension()"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The ``FileSelector`` widget allows browsing the filesystem on the server and selecting one or more files in a directory.\n",
+    "\n",
+    "For more information about listening to widget events and laying out widgets refer to the [widgets user guide](../../user_guide/Widgets.ipynb). Alternatively you can learn how to build GUIs by declaring parameters independently of any specific widgets in the [param user guide](../../user_guide/Param.ipynb). To express interactivity entirely using Javascript without the need for a Python server take a look at the [links user guide](../../user_guide/Param.ipynb).\n",
+    "\n",
+    "#### Parameters:\n",
+    "\n",
+    "For layout and styling related parameters see the [customization user guide](../../user_guide/Customization.ipynb).\n",
+    "\n",
+    "##### Core\n",
+    "\n",
+    "* **``directory``** (str): The directory to browse (cannot access files above this directory).\n",
+    "* **``file_pattern``** (str, default='*'): A glob-like query expression to limit the displayed files.\n",
+    "* **``only_files``** (bool, default=False): Whether to only allow selecting files.\n",
+    "* **``show_hidden``** (bool, default=False): Whether to show hidden files and directories (starting with a period).\n",
+    "* **``value``** (list[str]): A list of file names.\n",
+    "\n",
+    "##### Display\n",
+    "\n",
+    "* **``name``** (str): The title of the widget\n",
+    "* **``size``** (int): The number of items to show in the selected and unselected lists\n",
+    "\n",
+    "___"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "The ``FileSelector`` widget allows exploring the specified directory on the server's filesystem and any directories contained within it. The widget consists of the navigation bar with a number of buttons and the address bar:\n",
+    "\n",
+    "* Back (`◀`): Goes to the previous directory\n",
+    "* Forward (`▶`): Returns to the last directory after navigating back\n",
+    "* Up (`⬆`): Goes one directory up\n",
+    "* Address bar: Display the directory to navigate to\n",
+    "* Enter (`⬇`): Navigates to the directory in the address bar\n",
+    "\n",
+    "The actual file selector displays the contents of the current directory, to navigate to a subfolder click on a directory in the file selector and then hit the down arrow (`⬇`) in the navigation bar. Files and folders may be selected by selecting them in the browser on the left and moving them to the right with the arrow buttons:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "files = pn.widgets.FileSelector('~')\n",
+    "\n",
+    "files"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "To get the currently selected files simply access the `value` parameter:"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "files.value"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.7.5"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 4
+}

panel/tests/widgets/test_file_selector.py

@@ -0,0 +1,167 @@
+from __future__ import absolute_import, division, unicode_literals
+
+import os
+import shutil
+
+from collections import OrderedDict
+
+import pytest
+
+from panel.widgets import FileSelector
+
+@pytest.yield_fixture
+def test_dir():
+    test_dir = os.path.expanduser('~/test_dir')
+    os.mkdir(test_dir)
+    os.mkdir(os.path.expanduser('~/test_dir/subdir1'))
+    with open(os.path.expanduser('~/test_dir/subdir1/a'), 'a'):
+        pass
+    with open(os.path.expanduser('~/test_dir/subdir1/b'), 'a'):
+        pass
+    os.mkdir(os.path.expanduser('~/test_dir/subdir2'))
+    yield test_dir
+    shutil.rmtree(os.path.expanduser('~/test_dir'))
+
+
+def test_file_selector_init(test_dir):
+    selector = FileSelector(test_dir)
+
+    assert selector._selector.options == {
+        '\U0001f4c1subdir1': os.path.join(test_dir, 'subdir1'),
+        '\U0001f4c1subdir2': os.path.join(test_dir, 'subdir2')
+    }
+
+
+def test_file_selector_address_bar(test_dir):
+    selector = FileSelector(test_dir)
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+
+    assert not selector._go.disabled
+
+    selector._go.clicks = 1
+
+    assert selector._cwd == os.path.join(test_dir, 'subdir1')
+    assert selector._go.disabled
+    assert selector._forward.disabled
+    assert not selector._back.disabled
+    assert selector._selector.options == {
+        'a': os.path.join(test_dir, 'subdir1', 'a'),
+        'b': os.path.join(test_dir, 'subdir1', 'b')
+    }
+
+    selector._up.clicks = 1
+
+    selector._selector._lists[False].value = ['subdir1']
+
+    assert selector._directory.value == os.path.join(test_dir, 'subdir1')
+
+    selector._selector._lists[False].value = []
+
+    assert selector._directory.value == test_dir
+
+
+def test_file_selector_back_and_forward(test_dir):
+    selector = FileSelector(test_dir)
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+    selector._go.clicks = 1
+
+    assert selector._cwd == os.path.join(test_dir, 'subdir1')
+    assert not selector._back.disabled
+    assert selector._forward.disabled
+
+    selector._back.clicks = 1
+
+    assert selector._cwd == test_dir
+    assert selector._back.disabled
+    assert not selector._forward.disabled
+
+    selector._forward.clicks = 1
+
+    assert selector._cwd == os.path.join(test_dir, 'subdir1')
+
+
+def test_file_selector_up(test_dir):
+    selector = FileSelector(test_dir)
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+    selector._go.clicks = 1
+
+    assert selector._cwd == os.path.join(test_dir, 'subdir1')
+
+    selector._up.clicks = 1
+
+    assert selector._cwd == test_dir
+
+
+def test_file_selector_select_files(test_dir):
+    selector = FileSelector(test_dir)
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+    selector._go.clicks = 1
+
+    selector._selector._lists[False].value = ['a']
+    selector._selector._buttons[True].clicks = 1
+
+    assert selector.value == [os.path.join(test_dir, 'subdir1', 'a')]
+
+    selector._selector._lists[False].value = ['b']
+    selector._selector._buttons[True].clicks = 2
+
+    assert selector.value == [
+        os.path.join(test_dir, 'subdir1', 'a'),
+        os.path.join(test_dir, 'subdir1', 'b')
+    ]
+
+    selector._selector._lists[True].value = ['a', 'b']
+    selector._selector._buttons[False].clicks = 2
+
+    assert selector.value == []
+
+
+def test_file_selector_only_files(test_dir):
+    selector = FileSelector(test_dir, only_files=True)
+
+    selector._selector._lists[False].value = ['\U0001f4c1subdir1']
+    selector._selector._buttons[True].clicks = 1
+
+    assert selector.value == []
+    assert selector._selector._lists[False].options == ['\U0001f4c1subdir1', '\U0001f4c1subdir2']
+
+
+def test_file_selector_file_pattern(test_dir):
+    selector = FileSelector(test_dir, file_pattern='a')
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+    selector._go.clicks = 1
+
+    assert selector._selector._lists[False].options == ['a']
+
+
+def test_file_selector_multiple_across_dirs(test_dir):
+    selector = FileSelector(test_dir)
+
+    selector._selector._lists[False].value = ['\U0001f4c1subdir2']
+    selector._selector._buttons[True].clicks = 1
+
+    assert selector.value == [os.path.join(test_dir, 'subdir2')]
+
+    selector._directory.value = os.path.join(test_dir, 'subdir1')
+    selector._go.clicks = 1
+
+    selector._selector._lists[False].value = ['a']
+    selector._selector._buttons[True].clicks = 2
+
+    assert selector.value == [os.path.join(test_dir, 'subdir2'),
+                              os.path.join(test_dir, 'subdir1', 'a')]
+
+    selector._selector._lists[True].value = ['\U0001f4c1'+os.path.join('..', 'subdir2')]
+    selector._selector._buttons[False].clicks = 1
+
+    assert selector._selector.options == OrderedDict([
+        ('a', os.path.join(test_dir, 'subdir1', 'a')),
+        ('b', os.path.join(test_dir, 'subdir1', 'b'))
+    ])
+    assert selector._selector._lists[False].options == ['b']
+    assert selector.value == [os.path.join(test_dir, 'subdir1', 'a')]

panel/viewable.py

@@ -186,6 +186,8 @@ class Layoutable(param.Parameterized):
     def __init__(self, **params):
         if (params.get('width', None) is not None and
             params.get('height', None) is not None and
+            params.get('width_policy') is None and
+            params.get('height_policy') is None and
             'sizing_mode' not in params):
             params['sizing_mode'] = 'fixed'
         elif not self.param.sizing_mode.constant and not self.param.sizing_mode.readonly:

panel/widgets/__init__.py

@@ -4,8 +4,10 @@
 """
 from __future__ import absolute_import, division, unicode_literals
 
+from .ace import Ace  # noqa
 from .base import Widget, CompositeWidget # noqa
 from .button import Button, Toggle # noqa
+from .file_selector import FileSelector # noqa
 from .input import (# noqa
     ColorPicker, Checkbox, DatetimeInput, DatePicker, FileInput,
     LiteralInput, StaticText, TextInput, Spinner, PasswordInput,
@@ -22,4 +24,3 @@
     MultiSelect, RadioButtonGroup, RadioBoxGroup, Select, ToggleGroup
 )
 from .tables import DataFrame # noqa
-from .ace import Ace  # noqa

panel/widgets/base.py

@@ -136,9 +136,14 @@ class CompositeWidget(Widget):
     def __init__(self, **params):
         super(CompositeWidget, self).__init__(**params)
         layout = {p: getattr(self, p) for p in Layoutable.param
-                  if p != 'name' and getattr(self, p) is not None}
+                  if getattr(self, p) is not None}
         self._composite = self._composite_type(**layout)
         self._models = self._composite._models
+        self.param.watch(self._update_layout_params, list(Layoutable.param))
+
+    def _update_layout_params(self, *events):
+        for event in events:
+            setattr(self._composite, event.name, event.new)
 
     def select(self, selector=None):
         """
@@ -169,3 +174,6 @@ def _get_model(self, doc, root=None, parent=None, comm=None):
 
     def __contains__(self, object):
         return object in self._composite.objects
+
+    def _synced_params(self):
+        return []