set fixed name for the schedule image

website/migrations/0003_auto_20160816_1505.py

@@ -0,0 +1,21 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10 on 2016-08-16 13:05
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import website.models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('website', '0002_schedule'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='schedule',
+            name='image',
+            field=models.ImageField(storage=website.models.OverwriteStorage(), upload_to=website.models.Schedule.fixedname_upload_to, verbose_name='Stundenplan Bild'),
+        ),
+    ]

website/models.py

@@ -1,8 +1,12 @@
-from django.db import models
 from django.core.exceptions import ValidationError
+from django.core.files.storage import FileSystemStorage
+from django.db import models
+from django.db.models.signals import pre_delete
+from django.dispatch import receiver
 from django.template.defaultfilters import date as _date
 from django.utils.translation import ugettext_lazy as _
 
+import os
 
 class Settings(models.Model):
     """Configuration for Website App."""
@@ -38,6 +42,12 @@ def instance():
         except Settings.DoesNotExist:
             return None
 
+class OverwriteStorage(FileSystemStorage):
+    """Delete the old file so that the name is available"""
+    def get_available_name(self, name, max_length):
+        self.delete(name)
+        return super().get_available_name(name, max_length)
+
 class Schedule(models.Model):
     """A Schedule for a Degree during the Ophase"""
     class Meta:
@@ -50,9 +60,22 @@ class Meta:
         ('DSS', _('Distributed Software Systems')),
     )
 
+    def fixedname_upload_to(instance, filename):
+        """returns the path and name where the image should upload to"""
+        path = 'website/schedule/'
+        name = instance.degree.lower()
+        x, file_extension = os.path.splitext(filename)
+        return '{}{}{}'.format(path, name, file_extension)
+
     degree = models.CharField(max_length=3, choices=DEGREE_CHOICES, verbose_name=_('Abschluss'), unique=True)
-    image = models.ImageField(upload_to='website/schedule/', verbose_name=_('Stundenplan Bild'))
+    image = models.ImageField(verbose_name=_('Stundenplan Bild'),
+                upload_to=fixedname_upload_to, storage=OverwriteStorage())
     stand = models.DateField(verbose_name=_('Stand des Stundenplans'))
 
     def __str__(self):
         return '{} {}'.format(self.get_degree_display(), _date(self.stand, 'SHORT_DATE_FORMAT'))
+
+#Register an signal receiver so the image is deletet when the model is deleted
+@receiver(pre_delete, sender=Schedule)
+def schedule_delete(sender, instance, **kwargs):
+    instance.image.delete(False)