Django Export CSV admin action factory

export_csv_action.py

# Django Export CSV admin action factory
# https://gist.github.com/1411467
#
# Based on http://djangosnippets.org/snippets/2020/
# and http://djangosnippets.org/snippets/1697/
#
# Example usage:
#
# class MyUserAdmin(admin.ModelAdmin):
#     actions = (
#         export_csv_action(
#             description = "Export CSV",
#             fields = ('username', 'email',),
#             header = True,
#             labels = {
#                 'username': "User",
#                 'email': "Email",
#             },
#             filename = "users.csv",
#         ),
#     )

try:
    import unicodecsv as csv
except ImportError:
    import csv
from django.http import HttpResponse


def export_csv_action(description="Export CSV",
                      fields=None,
                      exclude=None,
                      header=True,
                      labels={},
                      encoding="utf8",
                      render_null=False,
                      filename=None):
    """
    Returns an admin action that exports the selected objects in CSV format.

        description: A string describing this admin action
        fields: A tuple or list of field names to include in the export
        exclude: A tuple or list of field names to exclude from the export
        header: A boolean indicating whether a header row should be included
        filename: The filename of the generated CSV report
    """

    def export_csv(modeladmin, request, queryset):
        """
        Generic CSV export admin action.
        """

        opts = modeladmin.model._meta

        if filename:
            csvfilename = filename
        else:
            csvfilename = '%s.csv' % unicode(opts).replace('.', '_')

        if fields:
            field_names = fields
        elif exclude:
            field_names = (
                set([field.name for field in opts.fields]) - set(exclude)
            )

        response = HttpResponse(content_type="text/csv")
        response['Content-Disposition'] = (
            "attachment; filename=%s" % csvfilename
        )

        writer = csv.writer(response, encoding=encoding)

        if header:
            header_row = []
            for name in field_names:
                if labels.has_key(name):
                    header_row.append(labels[name])
                else:
                    try:
                        field = getattr(modeladmin.model, name)
                        if hasattr(field, 'short_description'):
                            header_row.append(field.short_description)
                        else:
                            header_row.append(name)
                    except AttributeError:
                        header_row.append(name)
            writer.writerow(header_row)

        for obj in queryset:
            row = []
            for field in field_names:
                value = getattr(obj, field)
                if callable(value):
                    value = value()
                elif not render_null:
                    value = "" if value is None else value
                row.append(unicode(value).encode(encoding))
            writer.writerow(row)

        return response

    export_csv.short_description = description

    return export_csv