ImageField: save filename only - django

Question

I have model with ImageFile field:
def upload_course_cover(object, filename):
return '/media/courses/%s_%s' % (Course.objects.aggregate(Max('id'))['id__max'] + 1, filename)
class Course(models.Model):
# ...
cover = models.ImageField(upload_to=upload_course_cover, blank=True)
When the image is saved, into cover field will be writen full image path /media/courses/id_filename.ext, but I want store only image name id_filename.ext.
How to do it?

Answer 1

You cannot change what it stores in the database - unless you create your own custom field; or use a CharField.
If you just want to display the filename:
import os
c = Course.objects.get(pk=1)
fname = os.path.basename(c.cover.name)
# if cover's name is /hello/foo/bar.html
# fname will be bar.html
However, since you have image field - you can get lots of benefits out of it, for example - to get the URL to display the image in an img tag:
<img src="{{ c.cover.url }}"
alt="cover image for {{ c.name }}"
/>
You can also get some other benefits, for example:
class Course(models.Model):
# ....
cover_height = models.IntegerField()
cover_width = models.IntegerField()
cover = models.ImageField(upload_to=upload_course_cover,
height_field=cover_height,
width_field=cover_width,
# your other options...
)
Now you can do:
<img src="{{ c.cover.url }}" height="{{ c.cover_height }}" width="{{ c.cover_width }}">

Answer 2

"When the image is saved, into cover field will be writen full image path /media/courses/id_filename.ext"
To be precise, this is not true. Only the relative path from your MEDIA_ROOT is saved in the database. See https://docs.djangoproject.com/en/dev/ref/models/fields/#django.db.models.FileField.upload_to
(ImageField has the same properties as FileField)
To save only the filenames, you could
Add a new CharField to store the names
Use os.split() to get just the filename when called