django-exiffield：由于“CreateDate”和“DateTimeField”的格式不同，无法上传图片

Question

I'm a Django newbie, I hope you could help me.

I'm developing a photo gallery app, and right now I'm trying to implement EXIF data extraction. It's working pretty well with pictures that were uploaded before the model migration, however, whenever I try to upload a new picture, I get this error:

ValidationError at /admin/picture/picture/add/
['“2021:11:12 15:26:56” value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format.']

It looks like DateTimeField and EXIF's CreateDate use a different format: DateTimeField uses YYYY-MM-DD HH:MM, while EXIF's CreateDate uses YYYY:MM:DD HH:MM.

Is there any way to solve this?

Here's my picture model:

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

class Picture(models.Model):
    image = models.ImageField(upload_to=get_image_upload_path)
    [...]
    # METADATA
    created_on = models.DateTimeField(blank=True, editable=False, null=True)
    width = models.PositiveIntegerField(editable=False, blank=True, null=True)
    height = models.PositiveIntegerField(editable=False, blank=True, null=True)
    size = models.CharField(max_length=20, editable=False, blank=True, null=True)
    camera_make = models.CharField(max_length=20, editable=False, blank=True, null=True)
    camera_model = models.CharField(max_length=20, editable=False, blank=True, null=True)
    lens = models.CharField(max_length=20, editable=False, blank=True, null=True)
    iso = models.PositiveIntegerField(editable=False, blank=True, null=True)
    shutter_speed = models.CharField(max_length=20, editable=False, blank=True, null=True)
    latitude = models.CharField(max_length=20, editable=False, blank=True, null=True)
    longitude = models.CharField(max_length=20, editable=False, blank=True, null=True)
    exif = ExifField(
        source='image',
        denormalized_fields={
            'created_on': exifgetter('CreateDate'),
            'width': exifgetter('ImageWidth'),
            'height': exifgetter('ImageHeight'),
            'size': exifgetter('FileSize'),
            'camera_make': exifgetter('Make'),
            'camera_model': exifgetter('Model'),
            'lens': exifgetter('LensInfo'),
            'iso': exifgetter('ISO'),
            'shutter_speed': exifgetter('ShutterSpeed'),
            'latitude': exifgetter('GPSLatitude'),
            'longitude': exifgetter('GPSLongitude'),
        },
    )

And here's the full error:

Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'Make'
Could not execute `exifgetter("Model")` to extract value for `Picture.camera_model`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'Model'
Could not execute `exifgetter("LensInfo")` to extract value for `Picture.lens`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'LensInfo'
Could not execute `exifgetter("ISO")` to extract value for `Picture.iso`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'ISO'
Could not execute `exifgetter("ShutterSpeed")` to extract value for `Picture.shutter_speed`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'ShutterSpeed'
Could not execute `exifgetter("GPSLatitude")` to extract value for `Picture.latitude`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'GPSLatitude'
Could not execute `exifgetter("GPSLongitude")` to extract value for `Picture.longitude`
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/fields.py", line 186, in denormalize_exif
    value = extract_from_exif(exif_data)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/exiffield/getters.py", line 30, in inner
    return exif[field]['val']
KeyError: 'GPSLongitude'
Internal Server Error: /admin/picture/picture/add/
Traceback (most recent call last):
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/options.py", line 683, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/utils/decorators.py", line 133, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/views/decorators/cache.py", line 62, in _wrapped_view_func
    response = view_func(request, *args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/sites.py", line 242, in inner
    return view(request, *args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1885, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/utils/decorators.py", line 46, in _wrapper
    return bound_method(*args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/utils/decorators.py", line 133, in _wrapped_view
    response = view_func(request, *args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1745, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1797, in _changeform_view
    self.save_model(request, new_object, form, not add)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/contrib/admin/options.py", line 1220, in save_model
    obj.save()
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/picture/models.py", line 85, in save
    super(Picture, self).save(*args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/base.py", line 806, in save
    self.save_base(
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/base.py", line 857, in save_base
    updated = self._save_table(
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/base.py", line 1000, in _save_table
    results = self._do_insert(
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/base.py", line 1041, in _do_insert
    return manager._insert(
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/manager.py", line 85, in manager_method
    return getattr(self.get_queryset(), name)(*args, **kwargs)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/query.py", line 1434, in _insert
    return query.get_compiler(using=using).execute_sql(returning_fields)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1620, in execute_sql
    for sql, params in self.as_sql():
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1547, in as_sql
    value_rows = [
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1548, in <listcomp>
    [
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1549, in <listcomp>
    self.prepare_value(field, self.pre_save_val(field, obj))
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/sql/compiler.py", line 1487, in prepare_value
    value = field.get_db_prep_save(value, connection=self.connection)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 910, in get_db_prep_save
    return self.get_db_prep_value(value, connection=connection, prepared=False)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1546, in get_db_prep_value
    value = self.get_prep_value(value)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1524, in get_prep_value
    value = super().get_prep_value(value)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1403, in get_prep_value
    return self.to_python(value)
  File "/Users/temporaryadmin/DHTA_Projects/Group_Project/venv/lib/python3.8/site-packages/django/db/models/fields/__init__.py", line 1506, in to_python
    raise exceptions.ValidationError(
django.core.exceptions.ValidationError: ['"2021:11:12 15:26:56" value has an invalid format. It must be in YYYY-MM-DD HH:MM[:ss[.uuuuuu]][TZ] format.']

Thanks a lot in advance!

Answer 1

I managed to solve the issue, as exiffield has a specific getter for this:

get_datetaken -> Optional[datetime]

Get when the file was created as datetime

So what I did is the following:

class Picture(models.Model):
  image = models.ImageField(upload_to='images')
    [...]
  # METADATA
  created_on = models.DateTimeField(editable=False, blank=True, null=True)
  exif = ExifField(
    source='image',
    denormalized_fields={
        'created_on': get_datetaken,
    },
  )