CSV Generator

A configurable CSV Generator for Django

Support

Supports the following versions of Django:

• Django 2.2
• Django 3.0

Installation

pip install csv_generator

Add 'csv_generator' to the INSTALLED_APPS setting in your django project

INSTALLED_APPS += ('csv_generator',)

python manage.py migrate

Configuration

CSV Writer

By default csv_generator uses the unicode CSV writer class bundled with the app. However, you can use your own CSV Writer class by specifying the import path for your custom writer class (as a string) using the CSV_GENERATOR_WRITER_CLASS setting:

CSV_GENERATOR_WRITER_CLASS = 'my_app.utils.MyCustomCsvGeneratorClass'

Any custom CSV writer class must implement the same methods (with the same signatures) as the UnicodeWriter class bundled with this app.

Non model field attributes

It is also possible to process extra model attributes (non-field attributes) such as methods and properties defined on the model. Extra attributes which can be processed by the csv_generator are defined in the settings file using the following setting:

CSV_GENERATOR_AVAILABLE_ATTRIBUTES = {
    'all': {
        'commonattribute': 'An attribute that is common to all models in the system'
    },
    'myapp.mymodel': {
        'somecustomattribute': 'My custom model attribute'
    }
}

Each key in the CSV_GENERATOR_AVAILABLE_ATTRIBUTES dict should be in the format <app_label>.<model_name> (lower case). The value for each of these keys should be another dict where the key is the attribute name on the model and the value is the human readable description of the attribute used in the admin forms. The special case here is the all key in the CSV_GENERATOR_AVAILABLE_ATTRIBUTES. Values defined under the all key will be made available to all models in the system.

Each attribute defined can be a property or a method. Methods will be called when a csv file is generated. It is important to note that any method made available to the csv generator will be called with no arguments. As such the signature of the methods exposed to the csv generator should be callable without any arguments.

CSV Value Overrides

In some situations it may be desirable to override certain csv column values before they are written to the csv file. For example, by default, the CSV generator will render None values as 'None' in the CSV file. It may be preferable to render these values as empty strings. To achieve this, you can specify a CSV_GENERATOR_VALUE_OVERRIDES setting, which is a dictionary where the key is the value to be mapped, and the corresponding value is the overridden value to be rendered into the CSV column.

Example

CSV_GENERATOR_VALUE_OVERRIDES = {
    None: ''
}

In the example above, all None values will be rendered as empty strings in the generated CSV file. Note that the default behaviour is to render the raw values string represention by passing it through pythons str() function (e.g. str(None)).

Usage

Django Admin integration

To integrate CSV generator admin functionality for your models just call admin.register passing csv_generator.admin.CsvExportAdmin as the ModelAdmin class This will add an extra action to the listing view allowing you to export selected records as a csv file using one of your configured CSV generators.

Example

from csv_generator.admin import CsvExportAdmin
from django.contrib import admin
from my_app.models import MyModel

admin.site.register(MyModel, CsvExportAdmin)

Setting up a csv generator

Once logged into the Django admin you can create a csv generator instance. Each CSV generator has the following fields:

• title: Human readable name used to identify the CSV writer in form fields etc
• include_headings: Whether or not to write column headings to the generated csv file
• content_type: The content type this csv_generator can process

Once the CSV generator has been created you will be able to specify the columns on the specified content_type model to write out to generated CSV files. Each column has the following fields:

• column_heading: Will be used instead of the model fields verbose_name if it has been specified (verbose name is the default)
• model_field: The name of the field from the specified content type to write into the column
• order: The order of the csv column relative to other columns belonging to the specified csv generator instance
• generator: A foreign key to the generator instance that uses this column (not visible in the django admin)

Using the generators in your app

You can use the csv_generator in your own app.

Retrieving CsvGenerator models

For a particular model class or instance

from csv_generator.models import CsvGenerator
from my_app.models import MyModel

generators = CsvGenerator.objects.for_model(MyModel)
generators = CsvGenerator.objects.for_model(MyModel())

For a particular content_type

from csv_generator.models import CsvGenerator
from django.contrib.contenttypes.models import ContentType
from my_app.models import MyModel

ctype = ContentType.objects.get_for_model(MyModel)
generators = CsvGenerator.objects.for_content_type(ctype)

For a particular content_type id

from csv_generator.models import CsvGenerator
from django.contrib.contenttypes.models import ContentType
from my_app.models import MyModel

ctype = ContentType.objects.get_for_model(MyModel)
generators = CsvGenerator.objects.for_content_type_id(ctype.pk)

Generating CSV files

Write to file

from csv_generator.models import CsvGenerator
from my_app.models import MyModel

generator = CsvGenerator.objects.get(pk=1)  # Assume this is a generator instance for MyModel content type
file_handle = open('my_csv.csv', 'wB')
queryset = MyModel.objects.all()
csv_file = generator.generate(file_handle, queryset)

Write to Http Response

from csv_generator.models import CsvGenerator
from django.http import HttpResponse
from my_app.models import MyModel

generator = CsvGenerator.objects.get(pk=1)  # Assume this is a generator instance for MyModel content type
response = HttpResponse(content_type='text/csv')
response['Content-Disposition'] = 'attachment; filename="my_csv.csv"'
queryset = MyModel.objects.all()
response = generator.generate(response, queryset)

Release History

• 0.1: Initial Release
• 0.2: Bug fixes relating to missing templates in pypi package
• 0.3: Django 1.7 compatibility
• 0.4: Attribute descriptor/Empty cell implementation
• 0.5: ForeignKey descriptor implementation allowing foreign key and OneToOne key relationships to be traversed
• 0.6: Support for django 1.10, python 3.4 and python 3.5
• 0.7: Support for django 1.11
• 0.8: Support for django 2.0 and python 3.6
• 0.8.1: Support for django 2.1, 2.2 and python 3.7, 3.8
• 0.8.2: Fix regression where form would not instantiate correctly in django admin
• 0.9.0: Ensure content type options in admin forms are ordered by model name. Allow attribute values to be overridden at a global level.
• 0.9.1: Fix bug where an extra CsvGeneratorColumn record was automatically added when editing an existing CsvGenerator model instance.
• 1.0.0: Removed support for older, unsupported versions of django. Removed compatibility fixes and add support for django 3.0
• 1.0.1: Fixed bug with 'Take me back' button in django admin export form that caused csv file to be downloaded again.
• 1.0.2: Ensure changelist filters are persisted when the 'Take me back' button on the csv export view is clicked