Improve Download with Index and Filename parameters (#438)

* Add index to Download

* Add Download option for filename

If it is not used either 'self.view.title' or 'self.view.pipeline.table' will determine the filename.

Both will first go through a cleanup process using Django's slugify

* Pin sqlalchemy

* Add filename.ext as an option for download in views

lumen/tests/views/test_base.py

@@ -238,3 +238,32 @@ def test_view_title_download(set_root, view_type):
 
     button._on_click()
     assert button.data.startswith('data:text/plain;charset=UTF-8;base64')
+
+    assert view.download.filename is None
+    assert view.download.format == 'csv'
+
+
+@pytest.mark.parametrize("view_type", ("table", "hvplot"))
+def test_view_title_download_filename(set_root, view_type):
+    set_root(str(Path(__file__).parent.parent))
+    source = FileSource(tables={'test': 'sources/test.csv'})
+    view = {
+        'type': view_type,
+        'table': 'test',
+        'title': 'Test title',
+        'download': 'example.csv',
+    }
+
+    view = View.from_spec(view, source)
+
+    title = view.panel[0][0]
+    assert isinstance(title, pn.pane.HTML)
+
+    button = view.panel[0][1]
+    assert isinstance(button, DownloadButton)
+
+    button._on_click()
+    assert button.data.startswith('data:text/plain;charset=UTF-8;base64')
+
+    assert view.download.filename == 'example'
+    assert view.download.format == 'csv'

lumen/util.py

@@ -5,6 +5,7 @@
 import os
 import re
 import sys
+import unicodedata
 
 from functools import wraps
 from logging import getLogger
@@ -314,3 +315,25 @@ def wrapper(*args, **kwargs):
         return decorator(function)
 
     return decorator
+
+
+def slugify(value, allow_unicode=False) -> str:
+    """
+    Convert to ASCII if 'allow_unicode' is False. Convert spaces or repeated
+    dashes to single dashes. Remove characters that aren't alphanumerics,
+    underscores, or hyphens. Convert to lowercase. Also strip leading and
+    trailing whitespace, dashes, and underscores.
+
+    From: https://docs.djangoproject.com/en/4.0/_modules/django/utils/text/#slugify
+    """
+    value = str(value)
+    if allow_unicode:
+        value = unicodedata.normalize("NFKC", value)
+    else:
+        value = (
+            unicodedata.normalize("NFKD", value)
+            .encode("ascii", "ignore")
+            .decode("ascii")
+        )
+    value = re.sub(r"[^\w\s-]", "", value.lower())
+    return re.sub(r"[-\s]+", "-", value).strip("-_")

lumen/views/base.py

@@ -33,7 +33,7 @@
 from ..transforms.base import Transform
 from ..transforms.sql import SQLTransform
 from ..util import (
-    VARIABLE_RE, catch_and_notify, is_ref, resolve_module_reference,
+    VARIABLE_RE, catch_and_notify, is_ref, resolve_module_reference, slugify,
 )
 from ..validation import ValidationError
 
@@ -52,12 +52,20 @@ class Download(Component, Viewer):
     color = param.Color(default='grey', allow_None=True, doc="""
       The color of the download button.""")
 
-    hide = param.Boolean(default=False, doc="""
-      Whether the download button hides when not in focus.""")
+    filename = param.String(default=None, doc="""
+      The filename of the downloaded table.
+      File extension is added automatic based on the format.
+      If filename is not defined, it will be the name of the orignal table of the view.""")
 
     format = param.ObjectSelector(default=None, objects=DOWNLOAD_FORMATS, doc="""
       The format to download the data in.""")
 
+    hide = param.Boolean(default=False, doc="""
+      Whether the download button hides when not in focus.""")
+
+    index = param.Boolean(default=True, doc="""
+      Whether the downloaded table has an index.""")
+
     kwargs = param.Dict(default={}, doc="""
       Keyword arguments passed to the serialization function, e.g.
       data.to_csv(file_obj, **kwargs).""")
@@ -89,18 +97,19 @@ def _table_data(self) -> IO:
             io = BytesIO()
         data = self.view.get_data()
         if self.format == 'csv':
-            data.to_csv(io, **self.kwargs)
+            data.to_csv(io, index=self.index, **self.kwargs)
         elif self.format == 'json':
-            data.to_json(io, **self.kwargs)
+            data.to_json(io, index=self.index, **self.kwargs)
         elif self.format == 'xlsx':
-            data.to_excel(io, **self.kwargs)
+            data.to_excel(io, index=self.index, **self.kwargs)
         elif self.format == 'parquet':
-            data.to_parquet(io, **self.kwargs)
+            data.to_parquet(io, index=self.index, **self.kwargs)
         io.seek(0)
         return io
 
     def __panel__(self) -> DownloadButton:
-        filename = f'{self.view.pipeline.table}.{self.format}'
+        filename = self.filename or slugify(self.view.pipeline.table)
+        filename = f'{filename}.{self.format}'
         return DownloadButton(
             callback=self._table_data, filename=filename, color=self.color,
             size=18, hide=self.hide
@@ -176,7 +185,9 @@ def __init__(self, **params):
         if pipeline is None:
             raise ValueError("Views must declare a Pipeline.")
         if isinstance(params.get("download"), str):
-            params["download"] = Download(format=params["download"])
+            *filenames, ext = params.get("download").split(".")
+            filename = ".".join(filenames) or None
+            params["download"] = Download(filename=filename, format=ext)
         fields = list(pipeline.schema)
         for fp in self._field_params:
             if isinstance(self.param[fp], param.Selector):
@@ -372,7 +383,9 @@ def from_spec(
         # Resolve download options
         download_spec = spec.pop('download', {})
         if isinstance(download_spec, str):
-            download_spec = {'format': download_spec}
+            *filenames, ext = download_spec.split('.')
+            filename = '.'.join(filenames) or None
+            download_spec = {'filename': filename, 'format': ext}
         resolved_spec['download'] = Download.from_spec(download_spec)
 
         view = view_type(refs=refs, **resolved_spec)

setup.py

@@ -31,6 +31,7 @@ def get_setup_version(reponame):
     'sql': [
         'duckdb',
         'intake-sql',
+        'sqlalchemy <2',  # Don't work with pandas yet
     ],
     'tests': [
         'pytest',