Evgenij LegotskojFeb. 9, 2022, 5:11 a.m.

Django - Tutorial 056. How to convert image to WEBP format when saving to ImageField

WEBP is an image compression format that was introduced by Google in 2010. Its main advantage is its low size without visible loss of quality compared to formats such as JPEG or PNG. Therefore, it is quite logical to use this format for storing images on the site, especially if you do not need to store the original images on the site.

After a long search, I still did not find a ready-made and simple solution that would support converting images to WEBP format on the fly.
Therefore, I decided to write my own version, which eventually consists of a couple of dozen lines and is as simple as a wooden board.

Implementation

The whole implementation consists of two parts:

  • WEBPFieldFile - a class derived from ImageFieldFile, which saves a file with automatic conversion to WEBP format.
  • WEBPField - ImageField class that uses WEBPFieldFile instead of ImageFieldFile

And all this is located in one file fields.py.

To work with images, you need the Pillow library. So let's install it. However, even just to use ImageField fields, you will need this library.

pip install Pillow

fields.py

Create fields.py files in your application and add the following code to it

# -*- coding: utf-8 -*-

import io

from PIL import Image
from django.core.files.base import ContentFile
from django.db import models
from django.db.models.fields.files import ImageFieldFile


class WEBPFieldFile(ImageFieldFile):

    def save(self, name, content, save=True):
        content.file.seek(0)
        image = Image.open(content.file)
        image_bytes = io.BytesIO()
        image.save(fp=image_bytes, format="WEBP")
        image_content_file = ContentFile(content=image_bytes.getvalue())
        super().save(name, image_content_file, save)


class WEBPField(models.ImageField):
    attr_class = WEBPFieldFile

As you can see, in this code, in the WEBPFieldFile class, the save() method is overridden, which receives the name and contents of the file to be saved as an input argument, converts the contents of the file to the WEBP format, and then saves the file to disk. And the WEBPField class is exactly the same as ImageField , with the only difference being that it uses a modified variant of the class for image processing.

models.py

Now let's use the new image field in our photo model.

# -*- coding: utf-8 -*-

import os
import uuid

from django.conf import settings
from django.db import models
from django.utils.translation import gettext_lazy as _

from photo.fields import WEBPField


def image_folder(instance, filename):
    return 'photos/{}.webp'.format(uuid.uuid4().hex)


class Photo(models.Model):
    user = models.ForeignKey(to=settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    height = models.IntegerField(verbose_name=_('Height'), default=0, blank=True, null=True)
    width = models.IntegerField(verbose_name=_('Width'), default=0, blank=True, null=True)
    image = WEBPField(
        verbose_name=_('Image'),
        upload_to=image_folder,
        height_field='height',
        width_field='width'
    )

As you can see, using this WEBPField field is no different from using the standard ImageField field.

And as a bonus, in this code, in the image_folder function, I added the generation of a random unique file name using uuid .

We recommend hosting TIMEWEB
We recommend hosting TIMEWEB
Stable hosting, on which the social network EVILEG is located. For projects on Django we recommend VDS hosting.
- company blog
Support the author Donate

Очень годно!

Comments

Only authorized users can post comments.
Please, Log in or Sign up
Fornex

Let me recommend you a great European Fornex hosting.

Fornex has proven itself to be a stable host over the years.

For Django projects I recommend VPS hosting

Following the link you will receive a 5% discount on shared hosting services, dedicated servers, VPS and VPN

View Hosting
Share on social networks
Donate

The EVILEG project has switched to a non-commercial basis and will develop solely on the enthusiasm of the site creator, the enthusiasm of users, donations and the hosting referral system

Thank you for your support

Available ways to support the project

PayPal

PatreonYandex.MoneyMore
AB

C++ - Test 006. Enumerations

  • Result:30points,
  • Rating points-10
MH

C++ - Тест 003. Условия и циклы

  • Result:42points,
  • Rating points-8
AB

C++ - Test 005. Structures and Classes

  • Result:50points,
  • Rating points-4
Popular publications in the last 90 Days
Last comments

EVILEG-CORE. Caching properties of model objects using model_cached_property

Здравствуйте. В общем меня интересует такой вопрос. Я пробовал это на Like , Dislike. Как я понимаю если не перевалидировать кеш то ничего не изменится на странице. Вернётся значение из кэша? От…
A

Qt/C++ - Lesson 006. QSqlQueryModel – Tables in Qt with SQL-query

Здравствуйте! Подскажите как сделать запрос к базе SQLite с двумя параметрами, в итоге нужно получить не список строк, а только факт наличия строк, соответсвующи именно двум условиям. В SQL…
A

Django - Tutorial 011. Adding comments to the site based on Django

https://mir74.ru/27323-12-krasavic-sdelali-podarok-stalnomu-gigantu.-rabotnicy-mmk-snyalis-dlya-yubileynogo-fotokalendarya.html
a

Django - Tutorial 011. Adding comments to the site based on Django

I read that Post and got it fine and informative.https://aflife.ru/

Django - Tutorial 023. Like Dislike system using GenericForeignKey

Хорошо. Большое спасибо. Посмотрю что из этого получится.
Now discuss on the forum
o

Запрос на изменение БД с помощью оператора UPDATE и странное поведение QTableView

или запрос к базе так https://www.w3schools.com/sql/sql_ref_order_by.asp или сортировка в модели через прокси модель https://doc.qt.io/qt-5/qsortfilterproxymodel.html
o

Как очичтисть очередь событий для конпки

нужно сделать связку qml и c++, тяжелые задачи отправляются на обработку в с++, в qml остаются только быстрые. и у кнопок есть свойство enabled: true\false при запуске\остановке з…
A

Развертывание QML приложения

Полностью согласен, что пример не удачный, но я так как раз попытался выразить то, что вы далее описали с примером со скадой, часть .dll и часть .qml с интерпритацией. И в Вашем ответе я ув…
AB

Sorting the added QML elements in the ListModel

I am writing an alarm clock in QML, I am required to sort the alarms in ascending order (depending on the date or time (if there are several alarms on the same day). I've done the sorting …
EK

HTTP server на Qt

Давно было, уже не помню как, но разрулил. Спасибо :)
About
Services
© EVILEG 2015-2022
Recommend hosting TIMEWEB