Refinement of Assets and conversion of Image.

Writing the migrations when converting over an old plugin to use asset
is unfortunately a manual task. But it's not as difficult as it sounds.

Author: rstuart85

icekit/admin.py

@@ -9,7 +9,9 @@
 from django.contrib import admin
 from django.contrib.contenttypes.models import ContentType
 from django.http import JsonResponse
+from django.utils.module_loading import import_string
 from django.utils.translation import ugettext_lazy as _
+from polymorphic.admin import PolymorphicChildModelFilter
 from polymorphic.admin import PolymorphicParentModelAdmin
 
 from icekit import models
@@ -166,5 +168,18 @@ class MediaCategoryAdmin(admin.ModelAdmin):
     pass
 
 
+class AssetParentAdmin(PolymorphicParentModelAdmin):
+    base_model = models.Asset
+    list_display = ['title', 'get_admin_thumbnail', 'get_child_type', 'caption', ]
+    list_display_links = ['title']
+    filter_horizontal = ['categories', ]
+    list_filter = [PolymorphicChildModelFilter, 'categories']
+    search_fields = ['title', 'caption', 'admin_notes']
+    polymorphic_list = True
+
+    def get_child_models(self):
+        return [import_string(kls) for kls in settings.ASSET_CLASSES]
+
+admin.site.register(models.Asset, AssetParentAdmin)
 admin.site.register(models.Layout, LayoutAdmin)
 admin.site.register(models.MediaCategory, MediaCategoryAdmin)

icekit/assets/__init__.py

@@ -19,8 +19,8 @@ class Migration(migrations.Migration):
                 ('title', models.CharField(help_text='The title is shown in the "title" attribute', max_length=255, blank=True)),
                 ('caption', models.TextField(blank=True)),
                 ('admin_notes', models.TextField(help_text='Internal notes for administrators only.', blank=True)),
-                ('categories', models.ManyToManyField(related_name='assets_asset_related', to='icekit.MediaCategory', blank=True)),
-                ('polymorphic_ctype', models.ForeignKey(related_name='polymorphic_assets.asset_set+', editable=False, to='contenttypes.ContentType', null=True)),
+                ('categories', models.ManyToManyField(related_name='icekit_asset_related', to='icekit.MediaCategory', blank=True)),
+                ('polymorphic_ctype', models.ForeignKey(related_name='polymorphic_icekit.asset_set+', editable=False, to='contenttypes.ContentType', null=True)),
             ],
             options={
                 'abstract': False,

icekit/assets/apps.py

@@ -1,3 +1,9 @@
+import six
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+from fluent_contents.models import ContentItem
+from polymorphic.models import PolymorphicModel
+
 from . import abstract_models, managers
 
 
@@ -15,3 +21,40 @@ class MediaCategory(abstract_models.AbstractMediaCategory):
     A categorisation model for Media assets.
     """
     pass
+
+
+class Asset(PolymorphicModel):
+    """
+    A static asset available for use on a CMS page.
+    """
+    title = models.CharField(
+        max_length=255,
+        blank=True,
+        help_text=_('The title is shown in the "title" attribute'),
+    )
+    caption = models.TextField(
+        blank=True,
+    )
+    categories = models.ManyToManyField(
+        'icekit.MediaCategory',
+        blank=True,
+        related_name='%(app_label)s_%(class)s_related',
+    )
+    admin_notes = models.TextField(
+        blank=True,
+        help_text=_('Internal notes for administrators only.'),
+    )
+
+    def get_admin_thumbnail(self, width=150, height=150):
+        raise NotImplementedError
+    get_admin_thumbnail.short_description = "thumbnail"
+
+    def get_child_type(self):
+        return self.polymorphic_ctype
+    get_child_type.short_description = 'type'
+
+    def get_uses(self):
+        return [item.parent.get_absolute_url() for item in self.assetitem_set().all()]
+
+    def __str__(self):
+        return self.title

icekit/assets/migrations/__init__.py

@@ -1,55 +1,53 @@
 from django.core.exceptions import ValidationError
 from django.template import Context
 from django.template.loader import render_to_string
+from django.utils import six
+from django.utils.html import format_html
 from django.utils.safestring import mark_safe
 from django.db import models
 from django.utils import six
 from django.utils.encoding import python_2_unicode_compatible
 from django.utils.translation import ugettext_lazy as _
 from fluent_contents.models import ContentItem
+from icekit.models import Asset
 
 
 @python_2_unicode_compatible
-class AbstractImage(models.Model):
+class AbstractImage(Asset):
     """
     A reusable image.
     """
     image = models.ImageField(
         upload_to='uploads/images/',
         verbose_name=_('Image field'),
     )
-    title = models.CharField(
-        max_length=255,
-        blank=True,
-        help_text=_('Can be included in captions'),
-    )
     alt_text = models.CharField(
         max_length=255,
         help_text=_("A description of the image for users who don't see images. Leave blank if the image has no informational value."),
         blank=True,
     )
-    caption = models.TextField(
-        blank=True,
-    )
-    categories = models.ManyToManyField(
-        'icekit.MediaCategory',
-        blank=True,
-        related_name='%(app_label)s_%(class)s_related',
-    )
-    admin_notes = models.TextField(
-        blank=True,
-        help_text=_('Internal notes for administrators only.'),
-    )
     is_active = models.BooleanField(
         default=True,
     )
 
+    class Meta:
+        abstract = True
+
     def clean(self):
         if not (self.title or self.alt_text):
             raise ValidationError("You must specify either title or alt text")
 
-    class Meta:
-        abstract = True
+    def get_admin_thumbnail(self, width=150, height=150):
+        try:
+            from easy_thumbnails.files import get_thumbnailer
+        except ImportError:
+            return 'Thumbnail error: easy_thumbnails not installed'
+        try:
+            thumbnailer = get_thumbnailer(self.image)
+            thumbnail = thumbnailer.get_thumbnail({'size': (width, height)})
+            return format_html('<img class="thumbnail" src="{0}" />'.format(thumbnail.url))
+        except Exception as ex:
+            return 'Thumbnail exception: {0}'.format(ex)
 
     def __str__(self):
         return self.title or self.alt_text
@@ -79,7 +77,7 @@ class Meta:
         verbose_name_plural = _('Images')
 
     def __str__(self):
-        return six.text_type(self.image)
+        return six.text_type(self.asset)
 
     @property
     def caption(self):
@@ -95,7 +93,7 @@ def caption(self):
     @caption.setter
     def caption(self, value):
         """
-        If the caption property is assigned, make it use the
+        If the caption property is assigned to make it use the
         `caption_override` field.
 
         :param value: The caption value to be saved.

icekit/assets/models.py

@@ -1,23 +1,13 @@
 from django.contrib import admin
 
 from icekit.utils.admin.mixins import ThumbnailAdminMixin
+from polymorphic.admin import PolymorphicChildModelAdmin
 
 from . import models
 
 
-class ImageAdmin(ThumbnailAdminMixin, admin.ModelAdmin):
-    list_display = ['thumbnail', 'title', 'alt_text',]
-    list_display_links = ['alt_text', 'thumbnail']
-    filter_horizontal = ['categories', ]
-    list_filter = ['categories',]
-    search_fields = ['title', 'alt_text', 'caption', 'admin_notes', 'image']
-
+class ImageAdmin(PolymorphicChildModelAdmin):
+    base_model = models.Image
     change_form_template = 'image/admin/change_form.html'
 
-    # ThumbnailAdminMixin attributes
-    thumbnail_field = 'image'
-    thumbnail_options = {
-        'size': (150, 150),
-    }
-
 admin.site.register(models.Image, ImageAdmin)

icekit/assets/migrations/0001_initial.py renamed to icekit/migrations/0007_asset.py

@@ -0,0 +1,72 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+def create_assets(apps, schema_editor):
+    # We need to create a new asset for each image
+    Image = apps.get_model('icekit_plugins_image', 'Image')
+    Asset = apps.get_model('icekit', 'Asset')
+    for image in Image.objects.all():
+        # Create a new asset
+        asset = Asset()
+        asset.admin_notes = image.admin_notes
+        asset.caption = image.caption
+        asset.title = image.title
+        asset.save()
+        asset.categories.add(*image.categories.all())
+
+        # Set the asset_ptr on the image
+        image.asset_ptr = asset
+        image.save()
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('icekit', '0007_asset'),
+        ('icekit_plugins_image', '0008_auto_20160920_2114'),
+        ('icekit', '0006_auto_20150911_0744'),
+    ]
+
+    operations = [
+        # Add the ForeignKey first as not the primary key so we can fake it
+        migrations.AddField(
+            model_name='image',
+            name='asset_ptr',
+            field=models.OneToOneField(parent_link=True, auto_created=True, default=1, serialize=False, to='icekit.Asset'),
+            preserve_default=False,
+        ),
+        # Create asset links for existing images
+        migrations.RunPython(
+            create_assets
+        ),
+        migrations.RemoveField(
+            model_name='image',
+            name='admin_notes',
+        ),
+        migrations.RemoveField(
+            model_name='image',
+            name='caption',
+        ),
+        migrations.RemoveField(
+            model_name='image',
+            name='categories',
+        ),
+        migrations.RemoveField(
+            model_name='image',
+            name='id',
+        ),
+        migrations.RemoveField(
+            model_name='image',
+            name='title',
+        ),
+        # Make asset_ptr the primary key
+        migrations.AlterField(
+            model_name='image',
+            name='asset_ptr',
+            field=models.OneToOneField(parent_link=True, auto_created=True, primary_key=True, serialize=False, to='icekit.Asset'),
+            preserve_default=False,
+        ),
+    ]

icekit/models.py

@@ -610,6 +610,8 @@
 
 MIDDLEWARE_CLASSES += ('icekit.publishing.middleware.PublishingMiddleware', )
 
+ASSET_CLASSES = ('icekit.plugins.image.models.Image',)
+
 # MASTER PASSWORD #############################################################
 
 AUTHENTICATION_BACKENDS += ('master_password.auth.ModelBackend', )