django-exiffield

django-exiffield extracts exif information by utilizing the exiftool.

Requirements

Python 3.6.1 or newer
exiftool
Django >= 2.2

Installation

Install django-exiffield
```
pip install django-exiffield
```
Make sure exiftool is executable from you environment.

Integration

Let's assume we have an image Model with a single ImageField. To extract exif information for an attached image, add an ExifField, specify the name of the ImageField in the source argument

from django.db import models

from exiffield.fields import ExifField


class Image(models.Model):
    image = models.ImageField()
    exif = ExifField(
        source='image',
    )

and create a migration for the new field. That's it.

After attaching an image to your ImageField, the exif information is stored as a dict on the ExifField. Each exif information of the dictionary consists of two keys:

desc: A human readable description
val: The value for the entry.

In the following example we access the camera model

image = Image.objects.get(...)
print(image.exif['Model'])
# {
#     'desc': 'Camera Model Name',
#     'val': 'DMC-GX7',
# }

As the exif information is encoded in a simple dict you can iterate and access the values with all familiar dictionary methods.

Denormalizing Fields

Since the ExifField stores its data simply as text, it is not possible to filter or access indiviual values efficiently. The ExifField provides a convinient way to denormalize certain values using the denormalized_fields argument. It takes a dictionary with the target field as key and a simple getter function of type Callable[[Dict[Dict[str, str]]], Any]. To denormalize a simple value you can use the provided exiffield.getters.exifgetter

from django.db import models

from exiffield.fields import ExifField
from exiffield.getters import exifgetter


class Image(models.Model):
    image = models.ImageField()
    camera = models.CharField(
        editable=False,
        max_length=100,
    )
    exif = ExifField(
        source='image',
        denormalized_fields={
            'camera': exifgetter('Model'),
        },
    )

There are more predefined getters in exiffield.getters:

exifgetter(exif_key: str) -> str
Get an unmodified exif value.

get_type() -> str
Get file type, e.g. video or image

get_datetaken -> Optional[datetime]
Get when the file was created as datetime

get_orientation -> exiffield.getters.Orientation
Get orientation of media file. Possible values are LANDSCAPE and PORTRAIT.

get_sequenctype -> exiffield.getters.Mode
Guess if the image was taken in a sequence. Possible values are BURST, BRACKETING, TIMELAPSE and SINGLE.

get_sequencenumber -> int
Get image position in a sequence.

Development

This project uses poetry for packaging and managing all dependencies and pre-commit to run flake8, isort, mypy and black.

Clone this repository and run

poetry install
poetry run pre-commit install

to create a virtual enviroment containing all dependencies. Afterwards, You can run the test suite using

poetry run pytest

This repository follows the Conventional Commits style.

Cookiecutter template

This project was created using cruft and the cookiecutter-pyproject template. In order to update this repository to the latest template version run

cruft update

in the root of this repository.

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