Merge pull request pallets-eco#1038 from tandreas/csv_export

Implement CSV export for BaseModelView.

doc/introduction.rst

@@ -298,6 +298,12 @@ To **manage related models inline**::
 These inline forms can be customised. Have a look at the API documentation for
 :meth:`~flask_admin.contrib.sqla.ModelView.inline_models`.
 
+To **enable csv export** of the model view::
+
+ can_export = True
+
+This will add a button to the model view that exports records, truncating at :attr:`~flask_admin.model.BaseModelView.max_export_rows`.
+
 Adding Your Own Views
 =====================
 

flask_admin/_compat.py

@@ -31,6 +31,10 @@ def as_unicode(s):
 
  return str(s)
 
+ def csv_encode(s):
+ ''' Returns unicode string expected by Python 3's csv module '''
+ return as_unicode(s)
+
  # Various tools
  from functools import reduce
  from urllib.parse import urljoin, urlparse
@@ -50,6 +54,10 @@ def as_unicode(s):
 
  return unicode(s)
 
+ def csv_encode(s):
+ ''' Returns byte string expected by Python 2's csv module '''
+ return as_unicode(s).encode('utf-8')
+
  # Helpers
  reduce = __builtins__['reduce'] if isinstance(__builtins__, dict) else __builtins__.reduce
  from urlparse import urljoin, urlparse

flask_admin/model/base.py

@@ -1,8 +1,12 @@
 import warnings
 import re
+import csv
+import time
+
+from werkzeug import secure_filename
 
 from flask import (request, redirect, flash, abort, json, Response,
- get_flashed_messages)
+ get_flashed_messages, stream_with_context)
 from jinja2 import contextfunction
 from wtforms.fields import HiddenField
 from wtforms.fields.core import UnboundField
@@ -18,12 +22,11 @@
  get_redirect_target, flash_errors)
 from flask_admin.tools import rec_getattr
 from flask_admin._backwards import ObsoleteAttr
-from flask_admin._compat import iteritems, OrderedDict, as_unicode
+from flask_admin._compat import iteritems, OrderedDict, as_unicode, csv_encode
 from .helpers import prettify_name, get_mdict_item_or_list
 from .ajax import AjaxModelLoader
 from .fields import ListEditableFieldList
 
-
 # Used to generate filter query string name
 filter_char_re = re.compile('[^a-z0-9 ]')
 filter_compact_re = re.compile(' +')
@@ -95,6 +98,9 @@ class BaseModelView(BaseView, ActionsMixin):
  when there are too many columns to display in the list_view.
  """
 
+ can_export = False
+ """Is model list export allowed"""
+
  # Templates
  list_template = 'admin/model/list.html'
  """Default list view template"""
@@ -194,14 +200,25 @@ def formatter(view, context, model, name):
  pass
  """
 
+ column_formatters_export = None
+ """
+ Dictionary of list view column formatters to be used for export.
+
+ Defaults to column_formatters when set to None.
+
+ Functions the same way as column_formatters except
+ that macros are not supported.
+ """
+
  column_type_formatters = ObsoleteAttr('column_type_formatters', 'list_type_formatters', None)
  """
  Dictionary of value type formatters to be used in the list view.
 
- By default, two types are formatted:
+ By default, three types are formatted:
 
  1. ``None`` will be displayed as an empty string
  2. ``bool`` will be displayed as a checkmark if it is ``True``
+ 3. ``list`` will be joined using ', '
 
  If you don't like the default behavior and don't want any type formatters
  applied, just override this property with an empty dictionary::
@@ -237,6 +254,18 @@ def type_formatter(view, value):
  pass
  """
 
+ column_type_formatters_export = None
+ """
+ Dictionary of value type formatters to be used in the export.
+
+ By default, two types are formatted:
+
+ 1. ``None`` will be displayed as an empty string
+ 2. ``list`` will be joined using ', '
+
+ Functions the same way as column_type_formatters.
+ """
+
  column_labels = ObsoleteAttr('column_labels', 'rename_columns', None)
  """
  Dictionary where key is column name and value is string to display.
@@ -579,6 +608,12 @@ class MyModelView(BaseModelView):
  action_disallowed_list = ['delete']
  """
 
+ # Export settings
+ export_max_rows = None
+ """
+ Maximum number of rows allowed for export.
+ """
+
  # Various settings
  page_size = 20
  """
@@ -732,10 +767,17 @@ def _refresh_cache(self):
  else:
  self.column_choices = self._column_choices_map = dict()
 
+ # Column formatters
+ if self.column_formatters_export is None:
+ self.column_formatters_export = self.column_formatters
+
  # Type formatters
  if self.column_type_formatters is None:
  self.column_type_formatters = dict(typefmt.BASE_FORMATTERS)
 
+ if self.column_type_formatters_export is None:
+ self.column_type_formatters_export = dict(typefmt.EXPORT_FORMATTERS)
+
  if self.column_descriptions is None:
  self.column_descriptions = dict()
 
@@ -1214,7 +1256,8 @@ def _get_default_order(self):
  return None
 
  # Database-related API
- def get_list(self, page, sort_field, sort_desc, search, filters):
+ def get_list(self, page, sort_field, sort_desc, search, filters,
+ page_size=None):
  """
  Return a paginated and sorted list of models from the data source.
 
@@ -1231,6 +1274,10 @@ def get_list(self, page, sort_field, sort_desc, search, filters):
  :param filters:
  List of filter tuples. First value in a tuple is a search
  index, second value is a search value.
+ :param page_size:
+ Number of results. Defaults to ModelView's page_size. Can be
+ overriden to change the page_size limit. Removing the page_size
+ limit requires setting page_size to 0 or False.
  """
  raise NotImplementedError('Please implement get_list method')
 
@@ -1493,19 +1540,23 @@ def _get_field_value(self, model, name):
  """
  return rec_getattr(model, name)
 
- @contextfunction
- def get_list_value(self, context, model, name):
+ def _get_list_value(self, context, model, name, column_formatters,
+  column_type_formatters):
  """
- Returns the value to be displayed in the list view
+ Returns the value to be displayed.
 
  :param context:
- :py:class:`jinja2.runtime.Context`
+ :py:class:`jinja2.runtime.Context` if available
  :param model:
  Model instance
  :param name:
  Field name
+ :param column_formatters:
+ column_formatters to be used.
+ :param column_type_formatters:
+ column_type_formatters to be used.
  """
- column_fmt = self.column_formatters.get(name)
+ column_fmt = column_formatters.get(name)
  if column_fmt is not None:
  value = column_fmt(self, context, model, name)
  else:
@@ -1516,7 +1567,7 @@ def get_list_value(self, context, model, name):
  return choices_map.get(value) or value
 
  type_fmt = None
- for typeobj, formatter in self.column_type_formatters.items():
+ for typeobj, formatter in column_type_formatters.items():
  if isinstance(value, typeobj):
  type_fmt = formatter
  break
@@ -1525,6 +1576,44 @@ def get_list_value(self, context, model, name):
 
  return value
 
+ @contextfunction
+ def get_list_value(self, context, model, name):
+ """
+ Returns the value to be displayed in the list view
+
+ :param context:
+ :py:class:`jinja2.runtime.Context`
+ :param model:
+ Model instance
+ :param name:
+ Field name
+ """
+ return self._get_list_value(
+ context,
+ model,
+ name,
+ self.column_formatters,
+ self.column_type_formatters,
+ )
+
+ def get_export_value(self, model, name):
+ """
+ Returns the value to be displayed in export.
+ Allows export to use different (non HTML) formatters.
+
+ :param model:
+ Model instance
+ :param name:
+ Field name
+ """
+ return self._get_list_value(
+ None,
+ model,
+ name,
+ self.column_formatters_export,
+ self.column_type_formatters_export,
+ )
+
  # AJAX references
  def _process_ajax_references(self):
  """
@@ -1823,6 +1912,76 @@ def action_view(self):
  """
  return self.handle_action()
 
+ @expose('/export/csv/')
+ def export_csv(self):
+ """
+ Export a CSV of records.
+ """
+ return_url = get_redirect_target() or self.get_url('.index_view')
+
+ if not self.can_export:
+ flash(gettext('Permission denied.'))
+ return redirect(return_url)
+
+ # Macros in column_formatters are not supported.
+ # Macros will have a function name 'inner'
+ # This causes non-macro functions named 'inner' not work.
+ for col, func in iteritems(self.column_formatters):
+ if func.__name__ == 'inner':
+ raise NotImplementedError(
+ 'Macros not implemented. Override with '
+ 'column_formatters_export. Column: %s' % (col,)
+ )
+
+ # Grab parameters from URL
+ view_args = self._get_list_extra_args()
+
+ # Map column index to column name
+ sort_column = self._get_column_by_idx(view_args.sort)
+ if sort_column is not None:
+ sort_column = sort_column[0]
+
+ # Get count and data
+ count, data = self.get_list(0, sort_column, view_args.sort_desc,
+ view_args.search, view_args.filters,
+ page_size=self.export_max_rows)
+
+ # https://docs.djangoproject.com/en/1.8/howto/outputting-csv/
+ class Echo(object):
+ """
+ An object that implements just the write method of the file-like
+ interface.
+ """
+ def write(self, value):
+ """
+ Write the value by returning it, instead of storing
+ in a buffer.
+ """
+ return value
+
+ writer = csv.writer(Echo())
+
+ def generate():
+ # Append the column titles at the beginning
+ titles = [csv_encode(c[1]) for c in self._list_columns]
+ yield writer.writerow(titles)
+
+ for row in data:
+ vals = [csv_encode(self.get_export_value(row, c[0]))
+ for c in self._list_columns]
+ yield writer.writerow(vals)
+
+ filename = '%s_%s.csv' % (self.name,
+ time.strftime("%Y-%m-%d_%H-%M-%S"))
+
+ disposition = 'attachment;filename=%s' % (secure_filename(filename),)
+
+ return Response(
+ stream_with_context(generate()),
+ headers={'Content-Disposition': disposition},
+ mimetype='text/csv'
+ )
+
  @expose('/ajax/lookup/')
  def ajax_lookup(self):
  name = request.args.get('name')

flask_admin/model/typefmt.py

@@ -49,3 +49,8 @@ def list_formatter(view, values):
  bool: bool_formatter,
  list: list_formatter,
 }
+
+EXPORT_FORMATTERS = {
+ type(None): empty_formatter,
+ list: list_formatter,
+}

flask_admin/templates/bootstrap2/admin/model/list.html

@@ -26,6 +26,12 @@
  </li>
  {% endif %}
 
+ {% if admin_view.can_export %}
+ <li>
+ <a href="{{ get_url('.export_csv', **request.args) }}" title="{{ _gettext('Export') }}">{{ _gettext('Export') }}</a>
+ </li>
+ {% endif %}
+
  {% if filters %}
  <li class="dropdown">
  {{ model_layout.filter_options() }}

flask_admin/templates/bootstrap3/admin/model/list.html

@@ -26,6 +26,12 @@
  </li>
  {% endif %}
 
+ {% if admin_view.can_export %}
+ <li>
+ <a href="{{ get_url('.export_csv', **request.args) }}" title="{{ _gettext('Export') }}">{{ _gettext('Export') }}</a>
+ </li>
+ {% endif %}
+
  {% if filters %}
  <li class="dropdown">
  {{ model_layout.filter_options() }}