2. How to export CSV from Django admin?

You have been asked to add ability to export Hero and Villain from the admin. There are a number of third party apps which allow doing this, but its quite easy without adding another dependency. You will add an admin action to HeroAdmin and VillanAdmin.

An admin action always has this signature def admin_action(modeladmin, request, queryset):, alternatively you can add it directly as a method on the ModelAdmin like this:

class SomeModelAdmin(admin.ModelAdmin):

    def admin_action(self, request, queryset):

To add csv export to HeroAdmin you can do something like this:

actions = ["export_as_csv"]

def export_as_csv(self, request, queryset):
    pass

export_as_csv.short_description = "Export Selected"

This adds an action called export selected, which looks like this:

You will then change the export_as_csv to this:

import csv
from django.http import HttpResponse
...

def export_as_csv(self, request, queryset):

    meta = self.model._meta
    field_names = [field.name for field in meta.fields]

    response = HttpResponse(content_type='text/csv')
    response['Content-Disposition'] = 'attachment; filename={}.csv'.format(meta)
    writer = csv.writer(response)

    writer.writerow(field_names)
    for obj in queryset:
        row = writer.writerow([getattr(obj, field) for field in field_names])

    return response

This exports all of the selected rows. If you notice, export_as_csv doens’t have anything specific to Hero, so you can extract the method to a mixin.

With the changes, your code looks like this:

class ExportCsvMixin:
    def export_as_csv(self, request, queryset):

        meta = self.model._meta
        field_names = [field.name for field in meta.fields]

        response = HttpResponse(content_type='text/csv')
        response['Content-Disposition'] = 'attachment; filename={}.csv'.format(meta)
        writer = csv.writer(response)

        writer.writerow(field_names)
        for obj in queryset:
            row = writer.writerow([getattr(obj, field) for field in field_names])

        return response

    export_as_csv.short_description = "Export Selected"


@admin.register(Hero)
class HeroAdmin(admin.ModelAdmin, ExportCsvMixin):
    list_display = ("name", "is_immortal", "category", "origin", "is_very_benevolent")
    list_filter = ("is_immortal", "category", "origin", IsVeryBenevolentFilter)
    actions = ["export_as_csv"]

...


@admin.register(Villain)
class VillainAdmin(admin.ModelAdmin, ExportCsvMixin):
    list_display = ("name", "category", "origin")
    actions = ["export_as_csv"]

You can add such an export to other models by subclassing from ExportCsvMixin