Feature: Add naive plugin support for pinry

pinry/settings/base.py

@@ -21,6 +21,7 @@ INSTALLED_APPS = [
     'django_images',
     'core',
     'users',
+    'pinry_plugins.apps.PinryPluginsConfig',
 ]
 
 ROOT_URLCONF = 'pinry.urls'

pinry_plugins/admin.py

@@ -0,0 +1,3 @@
+from django.contrib import admin
+
+# Register your models here.

pinry_plugins/apps.py

@@ -0,0 +1,9 @@
+from django.apps import AppConfig
+
+
+class PinryPluginsConfig(AppConfig):
+    name = 'pinry_plugins'
+
+    def ready(self):
+        from pinry_plugins import builder   # noqa
+        builder.init()

pinry_plugins/batteries/plugin_example.py

@@ -0,0 +1,10 @@
+from core.models import Image
+from django_images.models import Thumbnail
+
+
+class Plugin:
+    def process_image_pre_creation(self, django_settings, image_instance: Image):
+        pass
+
+    def process_thumbnail_pre_creation(self, django_settings, thumbnail_instance: Thumbnail):
+        pass

pinry_plugins/builder/__init__.py

@@ -0,0 +1,5 @@
+from . import _loader
+
+
+def init():
+    _loader.init()

pinry_plugins/builder/_loader.py

@@ -0,0 +1,63 @@
+import logging
+
+from django.dispatch import receiver
+from django.utils.module_loading import import_string
+from django.conf import settings
+from django.db import models
+
+from core.models import Image
+from django_images.models import Thumbnail
+
+_plugins = getattr(settings, "ENABLED_PLUGINS", [])
+_plugin_instances = []
+
+
+def _load_plugins():
+    for plugin_path in _plugins:
+        plugin_cls = import_string(plugin_path)
+        _plugin_instances.append(plugin_cls())
+
+
+@receiver(models.signals.pre_save, sender=Image)
+def process_image_pre_creation(sender, instance: Image, **kwargs):
+    # FIXME(winkidney): May have issue on determining if it
+    #  is created or not
+    if instance.pk is not None:
+        return
+    for plugin in _plugin_instances:
+        process_fn = getattr(plugin, "process_image_pre_creation")
+        try:
+            process_fn(
+                django_settings=settings,
+                image_instance=instance,
+            )
+        except Exception:
+            logging.exception(
+                "Error occurs while trying to access plugin's pin_pre_save "
+                "for plugin %s" % plugin
+            )
+
+
+@receiver(models.signals.pre_save, sender=Thumbnail)
+def process_thumbnail_pre_creation(sender, instance: Thumbnail, **kwargs):
+    # FIXME(winkidney): May have issue on determining if it
+    #  is created or not
+    if instance.pk is not None:
+        return
+
+    for plugin in _plugin_instances:
+        process_fn = getattr(plugin, "process_thumbnail_pre_creation")
+        try:
+            process_fn(
+                django_settings=settings,
+                thumbnail_instance=instance,
+            )
+        except Exception:
+            logging.exception(
+                "Error occurs while trying to access plugin's process_thumbnail_pre_creation "
+                "for plugin %s" % plugin
+            )
+
+
+def init():
+    _load_plugins()

pinry_plugins/models.py

@@ -0,0 +1,3 @@
+from django.db import models
+
+# Create your models here.

pinry_plugins/tests.py

@@ -0,0 +1,3 @@
+from django.test import TestCase
+
+# Create your tests here.

pinry_plugins/views.py

@@ -0,0 +1,3 @@
+from django.shortcuts import render
+
+# Create your views here.