django-extra-tools 0.4.1

A set of functions related with Django

Table of contents

• Installation

• Quick start

• Template filters

  • parse_datetime

  • parse_date

  • parse_time

  • parse_duration

• Aggregation

  • First

  • Last

  • Median

  • StringAgg

• Model mixins

  • CreatedAtMixin

  • CreatedByMixin

  • UpdatedAtMixin

  • UpdatedByMixin

  • DeletedAtMixin

  • DeletedByMixin

  • CreatedMixin

  • UpdatedMixin

  • DeletedMixin

• Database functions

  • batch_qs

  • pg_version

• HTTP Response

  • HttpResponseGetFile

• WSGI Request

  • get_client_ip

• Management

  • OneInstanceCommand

  • NagiosCheckCommand

• Middleware

  • XhrMiddleware

• Auth Backend

  • ThroughSuperuserModelBackend

• Permissions

  • view_(content_types) permissions

• Lockers

  • FileLocker

  • CacheLocker

Installation

pip install django-extra-tools

Quick start

Enable django-extra-tools

INSTALLED_APPS = [
    …
    'django_extra_tools',
]

Install SQL functions

python manage.py migrate

Template filters

parse_datetime

Parse datetime from string.

{% load parse %}

{{ string_datetime|parse_datetime|date:"Y-m-d H:i" }}

parse_date

Parse date from string.

{% load parse %}

{{ string_date|parse_date|date:"Y-m-d" }}

parse_time

Parse time from string.

{% load parse %}

{{ string_time|parse_time|date:"H:i" }}

parse_duration

Parse duration (timedelta) from string.

{% load parse %}

{{ string_duration|parse_duration }}

Aggregation

First

Returns the first non-NULL item.

from django_extra_tools.db.models.aggregates import First

Table.objects.aggregate(First('col1', order_by='col2'))

Last

Returns the last non-NULL item.

from django_extra_tools.db.models.aggregates import Last

Table.objects.aggregate(Last('col1', order_by='col2'))

Median

Returns median value.

from django_extra_tools.db.models.aggregates import Median

Table.objects.aggregate(Median('col1'))

StringAgg

Combines the values as the text. Fields are separated by a “separator”.

from django_extra_tools.db.models.aggregates import StringAgg

Table.objects.aggregate(StringAgg('col1'))

Model mixins

CreatedAtMixin

Add created_at field to model.

from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.CreatedAtMixin, models.Model):
    pass

model = MyModel()
print(model.created_at)

CreatedByMixin

Add created_by field to model.

from django.contrib.auth.models import User
from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.CreatedByMixin, models.Model):
    pass

user = User.objects.get(username='user')
model = MyModel(created_by=user)
print(model.created_by)

UpdatedAtMixin

Add updated_at field to model.

from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.UpdatedAtMixin, models.Model):
    operation = models.CharField(max_length=10)

model = MyModel()
print(model.updated_at)
model.operation = 'update'
model.save()
print(model.updated_at)

UpdatedByMixin

Add updated_by field to model.

from django.contrib.auth.models import User
from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.UpdatedByMixin, models.Model):
    operation = models.CharField(max_length=10)

user = User.objects.get(username='user')
model = MyModel()
print(model.updated_by)
model.operation = 'update'
model.save_by(user)
print(model.updated_by)

DeletedAtMixin

Add deleted_at field to model.

from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.DeletedAtMixin, models.Model):
    pass

model = MyModel()
print(model.deleted_at)
model.delete()
print(model.deleted_at)

DeletedByMixin

Add deleted_by field to model.

from django.contrib.auth.models import User
from django.db import models
from django_extra_tools.db.models import timestampable

class MyModel(timestampable.DeletedByMixin, models.Model):
    pass

user = User.objects.get(username='user')
model = MyModel()
print(model.deleted_by)
model.delete_by(user)
print(model.deleted_by)

CreatedMixin

Add created_at and created_by fields to model.

UpdatedMixin

Add updated_at and updated_by fields to model.

DeletedMixin

Add deleted_at and deleted_by fields to model.

Database functions

batch_qs

Returns a (start, end, total, queryset) tuple for each batch in the given queryset.

from django_extra_tools.db.models import batch_qs

qs = Table.objects.all()
start, end, total, queryset = batch_qs(qs, 10)

pg_version

Return tuple with PostgreSQL version of a specific connection.

from django_extra_tools.db.models import pg_version

version = pg_version()

HTTP Response

HttpResponseGetFile

An HTTP response class with the “download file” headers.

from django_extra_tools.http import HttpResponseGetFile

return HttpResponseGetFile(filename='file.txt', content=b'file content', content_type='file/text')

WSGI Request

get_client_ip

Get the client IP from the request.

from django_extra_tools.wsgi_request import get_client_ip

ip = get_client_ip(request)

You can configure list of local IP’s by setting PRIVATE_IPS_PREFIX

PRIVATE_IPS_PREFIX = ('10.', '172.', '192.', )

Management

OneInstanceCommand

A management command which will be run only one instance of command with name name. No other command with name name can not be run in the same time.

from django_extra_tools.management import OneInstanceCommand

class Command(OneInstanceCommand):
    name = 'mycommand'

    def handle_instance(self, *args, **options):
        # some operations

    def lock_error_handler(self, exc):
        # Own error handler
        super(Command, self).lock_error_handler(exc)

NagiosCheckCommand

A management command which perform a Nagios check.

from django_extra_tools.management import NagiosCheckCommand

class Command(NagiosCheckCommand):
    def handle_nagios_check(self, *args, **options):
        return self.STATE_OK, 'OK'

Middleware

XhrMiddleware

This middleware allows cross-domain XHR using the html5 postMessage API.

MIDDLEWARE_CLASSES = (
    ...
    'django_extra_tools.middleware.XhrMiddleware'
)

XHR_MIDDLEWARE_ALLOWED_ORIGINS = '*'
XHR_MIDDLEWARE_ALLOWED_METHODS = ['POST', 'GET', 'OPTIONS', 'PUT', 'DELETE']
XHR_MIDDLEWARE_ALLOWED_HEADERS = ['Content-Type', 'Authorization', 'Location', '*']
XHR_MIDDLEWARE_ALLOWED_CREDENTIALS = 'true'
XHR_MIDDLEWARE_EXPOSE_HEADERS = ['Location']

Auth Backend

ThroughSuperuserModelBackend

Allow to login to user account through superuser login and password.

Add ThroughSuperuserModelBackend to AUTHENTICATION_BACKENDS:

AUTHENTICATION_BACKENDS = (
    'django.contrib.auth.backends.ModelBackend',
    'django_extra_tools.auth.backends.ThroughSuperuserModelBackend',
)

Optionally You can configure username separator (default is colon):

AUTH_BACKEND_USERNAME_SEPARATOR = ':'

Now You can login to user account in two ways:

• provide username=’user1’ and password=’user password’

• provide username=’superuser username:user1’ and password=’superuser password’

Permissions

view_(content_types) permissions

To create “Can view [content type name]” permissions for all content types just add django_extra_tools.auth.view_permissions at the end of INSTALLED_APPS

INSTALLED_APPS = [
    …
    'django_extra_tools.auth.view_permissions'
]

and run migration

python manage.py migrate

Lockers

Function to set lock hook.

from django_extra_tools.lockers import lock

lock('unique_lock_name')

Next usage of lock on the same lock name raises LockError exception.

You can configure locker mechanism through DEFAULT_LOCKER_CLASS settings or directly:

from django_extra_tools.lockers import FileLocker

lock = FileLocker()('unique_lock_name')

FileLocker

This is a default locker.

This locker creates a unique_lock_name.lock file in temp directory.

You can configure this locker through settings:

DEFAULT_LOCKER_CLASS = 'django_extra_tools.lockers.FileLocker'

CacheLocker

This locker creates a locker-unique_lock_name key in cache.

You can configure this locker through settings:

DEFAULT_LOCKER_CLASS = 'django_extra_tools.lockers.CacheLocker'