Add a field+widgets for uploading images into a bytea column

Bypasses the annoying django handling and also doesn't require a special
table. PostgreSQL has no problem storing small things inline and toast
makes it transparent...

1 files changed, 54 insertions, 0 deletions

diff --git a/postgresqleu/util/fields.py b/postgresqleu/util/fields.py
index b1ed1190..33d52699 100644
--- a/postgresqleu/util/fields.py
+++ b/postgresqleu/util/fields.py
@@ -1,4 +1,6 @@
 from django.db import models
+from django.core.exceptions import ValidationError
+from .forms import ImageBinaryFormField
 
 
 class LowercaseEmailField(models.EmailField):
@@ -7,3 +9,55 @@ class LowercaseEmailField(models.EmailField):
         if value is not None:
             value = value.lower()
         return value
+
+
+class ImageBinaryField(models.Field):
+    empty_values = [None, b'']
+
+    def __init__(self, *args, **kwargs):
+        ml = kwargs.pop('max_length', None)
+        super(ImageBinaryField, self).__init__(*args, **kwargs)
+        self.max_length = ml
+
+    def deconstruct(self):
+        name, path, args, kwargs = super(ImageBinaryField, self).deconstruct()
+        return name, path, args, kwargs
+
+    def get_internal_type(self):
+        return "ImageBinaryField"
+
+    def get_placeholder(self, value, compiler, connection):
+        return '%s'
+
+    def get_default(self):
+        return b''
+
+    def db_type(self, connection):
+        return 'bytea'
+
+    def get_db_prep_value(self, value, connection, prepared=False):
+        value = super(ImageBinaryField, self).get_db_prep_value(value, connection, prepared)
+        if value is not None:
+            return connection.Database.Binary(value)
+        return value
+
+    def value_to_string(self, obj):
+        """Binary data is serialized as base64"""
+        return b64encode(force_bytes(self.value_from_object(obj))).decode('ascii')
+
+    def to_python(self, value):
+        if self.max_length is not None and len(value) > self.max_length:
+            raise ValidationError("Maximum size of file is {} bytes".format(self.max_length))
+
+        return value
+
+    def save_form_data(self, instance, data):
+        if data is not None:
+            if not data:
+                data = b''
+            setattr(instance, self.name, data)
+
+    def formfield(self, **kwargs):
+        defaults = {'form_class': ImageBinaryFormField}
+        defaults.update(kwargs)
+        return super(ImageBinaryField, self).formfield(**defaults)