From c905276c4570c8da4b38d5eab474bde3d7764adf Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Fr=C3=A9d=C3=A9ric=20P=C3=A9ters?= <fpeters@entrouvert.com>
Date: Thu, 12 Jul 2018 21:32:59 +0200
Subject: [PATCH] general: keep a redirect on slug and parent changes (#20760)

---
 combo/data/models.py | 22 ++++++++++++++++++++++
 tests/test_public.py | 18 ++++++++++++++++++
 2 files changed, 40 insertions(+)

diff --git a/combo/data/models.py b/combo/data/models.py
index 0f937dba..825ab3bc 100644
--- a/combo/data/models.py
+++ b/combo/data/models.py
@@ -34,7 +34,9 @@ from django.core.exceptions import ObjectDoesNotExist, ValidationError, Permissi
 from django.core import serializers
 from django.db import models, transaction
 from django.db.models.base import ModelBase
+from django.db.models.signals import pre_save
 from django.db.models import Max
+from django.dispatch import receiver
 from django.forms import models as model_forms
 from django import forms
 from django import template
@@ -1280,3 +1282,23 @@ class ExternalLinkSearchItem(models.Model):
     text = models.TextField(blank=True)
     url = models.CharField(_('URL'), max_length=200, blank=True)
     last_update_timestamp = models.DateTimeField(auto_now=True)
+
+
+@receiver(pre_save, sender=Page)
+def create_redirects(sender, instance, raw, **kwargs):
+    if raw or not instance.id or instance.snapshot_id:
+        return
+    try:
+        old_page = Page.objects.get(id=instance.id)
+    except Page.DoesNotExist:
+        return
+    if old_page.slug == instance.slug and old_page.parent_id == instance.parent_id:
+        return
+    affected_pages = level_pages = [old_page]
+    while True:
+        level_pages = Page.objects.filter(parent_id__in=[x.id for x in level_pages]).select_related('parent')
+        if len(level_pages) == 0:
+            break
+        affected_pages.extend(level_pages)
+    for page in affected_pages:
+        Redirect(page=page, old_url=page.get_online_url()).save()
diff --git a/tests/test_public.py b/tests/test_public.py
index 7c3ec9cd..1a57fd5d 100644
--- a/tests/test_public.py
+++ b/tests/test_public.py
@@ -609,3 +609,21 @@ def test_redirects(app):
     redirect = Redirect(old_url='/whatever/', page=page2)
     redirect.save()
     assert app.get('/whatever/', status=301).location == '/second/'
+
+    # rename page
+    page3.slug = 'third2'
+    page3.save()
+    assert app.get('/second/third2/', status=200)
+    assert app.get('/second/third/', status=301).location == '/second/third2/'
+
+    page2.slug = 'second2'
+    page2.save()
+    assert app.get('/second/third/', status=301).location == '/second2/third2/'
+    assert app.get('/second/third2/', status=301).location == '/second2/third2/'
+    assert app.get('/second/', status=301).location == '/second2/'
+
+    # change parent
+    page3.parent = None
+    page3.save()
+    assert app.get('/second/third/', status=301).location == '/third2/'
+    assert app.get('/second2/third2/', status=301).location == '/third2/'