django-tabular-export 1.2.1
Simple spreadsheet exports from Django
License: CC0

=====================
django-tabular-export
=====================

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Simple spreadsheet exports from Django 1.8+

Documentation
-------------

This module contains functions which take (headers, rows) pairs and return HttpResponses with either XLSX or
CSV downloads and Django admin actions which can be added to any ModelAdmin for generic exports. It provides
two functions (``export_to_csv_response`` and ``export_to_xlsx_response``) which take a filename,
a list of column headers, and a Django ``QuerySet``, list-like object, or generator and return a response.

Goals
~~~~~

* This project is not intended to be a general-purpose spreadsheet manipulation library. The only goal is to
  export data quickly and safely.
* The API is intentionally simple, giving you full control over the display and formatting of headers or your
  data. ``flatten_queryset`` has special handling for only two types of data: ``None`` will be converted to an
  empty string and ``date`` or ``datetime`` instances will serialized using ``isoformat()``. All
  other values will be specified as the text data type to avoid data corruption in Excel if the values happen
  to resemble a date in the current locale.
* **Unicode-safety**: input values, including lazy objects, are converted using Django's
  `force_text <https://docs.djangoproject.com/en/1.9/ref/utils/#django.utils.encoding.force_text>`_
  function and will always be emitted as UTF-8
* **Performance**: the code is known to work with data sets up to hundreds of thousands of rows. CSV responses
  use ``StreamingHttpResponse``, use minimal memory, and start very quickly. Excel (XLSX) responses cannot be
  streamed but `xlsxwriter <https://pypi.python.org/pypi/XlsxWriter>`_ is one of the faster implementations
  and its memory-size optimizations are enabled.

Quickstart
----------

Install django-tabular-export::

    pip install django-tabular-export

Then use it in a project::

    from tabular_export.core import export_to_csv_response, export_to_excel_response, flatten_queryset

    def my_view(request):
        return export_to_csv_response('test.csv', ['Column 1'], [['Data 1'], ['Data 2']])


    def my_other_view(request):
        headers = ['Title', 'Date Created']
        rows = MyModel.objects.values_list('title', 'date_created')
        return export_to_excel_response('items.xlsx', headers, rows)


    def export_using_a_generator(request):
        headers = ['A Number']

        def my_generator():
            for i in range(0, 100000):
                yield (i, )

        return export_to_excel_response('numbers.xlsx', headers, my_generator())

    def export_renaming_columns(request):
        qs = MyModel.objects.filter(foo="…").select_related("…")
        headers, data = flatten_queryset(qs, field_names=['title', 'related_model__title_en'],
                                         extra_verbose_names={'related_model__title_en': 'English Title'})
        return export_to_csv_response('custom_export.csv', headers, data)


Admin Integration
~~~~~~~~~~~~~~~~~

There are two convenience `admin actions <https://docs.djangoproject.com/en/1.9/ref/contrib/admin/actions/>`_
which make it simple to add “Export to Excel” and “Export to CSV” actions::

    from tabular_export.admin import export_to_csv_action, export_to_excel_action

    class MyModelAdmin(admin.ModelAdmin):
        actions = (export_to_excel_action, export_to_csv_action)

The default columns will be the same as you would get calling ``values_list`` on your ``ModelAdmin``'s default
queryset as returned by ``ModelAdmin.get_queryset()``. If you want to customize this, simply declare a new
action on your ``ModelAdmin`` which does whatever data preparation is necessary::

    from tabular_export.admin import export_to_excel_action

    class MyModelAdmin(admin.ModelAdmin):
        actions = ('export_batch_summary_action', )

        def export_batch_summary_action(self, request, queryset):
            headers = ['Batch Name', 'My Computed Field']
            rows = queryset.annotate("…").values_list('title', 'computed_field_name')
            return export_to_excel_response('batch-summary.xlsx', headers, rows)
        export_batch_summary_action.short_description = 'Export Batch Summary'


Debugging
~~~~~~~~~

The ``TABULAR_RESPONSE_DEBUG = True`` setting will cause all views to return HTML tables