ImageParser Class is used to parse an image from external url and save it to Django model field

image_url_to_file.py

import requests
import tempfile

from django.core import files


def image_url_to_file(image_url):

    # Steam the image from the url
    request = requests.get(image_url, stream=True)

    # Was the request OK?
    if request.status_code != requests.codes.ok:
        # Nope, error handling, skip file etc etc etc
        return

    # Get the filename from the url, used for saving later
    file_name = image_url.split('/')[-1]

    # Create a temporary file
    lf = tempfile.NamedTemporaryFile()

    # Read the streamed image in sections
    for block in request.iter_content(1024 * 8):

        # If no more file then stop
        if not block:
            break

        # Write image block to temporary file
        lf.write(block)

    # Save the temporary image to the model#
    # This saves the model so be sure that is it valid
    # getattr(obj, fieldname).save(file_name, files.File(lf))
    return file_name, files.File(lf)

ImageParserMixin.py

from django.db import models
from django.db.models.base import ModelBase

from .image_url_to_file import image_url_to_file


class ImageParserMixin(object):
    """
    ImageParser Class is used to parse an image from external url and save it to model field

    the fields can be mentioned under meta class as:

    /**
     *   class MyModel(ImageParserMixin, models.Model):
     *       ...
     *       ...
     *       image_field_1 = models.ImageField(...)
     *       image_field_2 = models.ImageField(...)
     *       ...
     *       url_to_image_fields = ['image_field_1', 'image_field_2', ... ]
     *
     */

    you can call  `{image_field_name}_get_from_url(url)` to save an image into the field.
    eg:
     `image_field_1_get_from_url(url)(url='http://example.com/../.../image_url.png')
    

    In short;
    After overriding the model from `ImageParserMixin` add field names to `url_to_image_fields` list.
    you can add image to model via '{field_name}_get_from_url(url)'

    """

    url_to_image_fields = []

    def __init__(self, *args, **kwargs):

        url_to_image_fields = getattr(self, 'url_to_image_fields', [])
        
        if url_to_image_fields:
            url_to_image_fields = [field for field in url_to_image_fields \
                                   if hasattr(getattr(self, field), '_get_image_dimensions')]  # TODO: A better Validation needed

            # image_url_to_model
            def set_function(field_name):
                def image_parser_function(url):
                    name, file = image_url_to_file(url)
                    img = getattr(self, field_name, None)
                    img.save(name, file)
                    setattr(self, field_name, img)
                return image_parser_function
        
            func_name = "%s_get_from_url"
            for field in url_to_image_fields:
                setattr(self, func_name % field, set_function(field))
            delattr(self.__class__, 'url_to_image_fields')
        super().__init__(*args, **kwargs)