✨(backend) refactor indexation signals and fix circular import issues

Signed-off-by: Fabre Florian <ffabre@hybird.org>

src/backend/core/signals.py

@@ -0,0 +1,28 @@
+"""
+Declare and configure the signals for the impress core application
+"""
+
+from django.db.models import signals
+from django.dispatch import receiver
+
+from . import models
+from .tasks.find import trigger_document_indexer
+
+
+@receiver(signals.post_save, sender=models.Document)
+def document_post_save(sender, instance, **kwargs):  # pylint: disable=unused-argument
+    """
+    Asynchronous call to the document indexer at the end of the transaction.
+    Note : Within the transaction we can have an empty content and a serialization
+    error.
+    """
+    trigger_document_indexer(instance, on_commit=True)
+
+
+@receiver(signals.post_save, sender=models.DocumentAccess)
+def document_access_post_save(sender, instance, created, **kwargs):  # pylint: disable=unused-argument
+    """
+    Asynchronous call to the document indexer at the end of the transaction.
+    """
+    if not created:
+        trigger_document_indexer(instance.document, on_commit=True)