Merge branch '2-optimise-query-count' into 'master'

Resolve "Optimise query count"

Closes #2

See merge request !1

favicon/migrations/0004_faviconimg_favicon_size_rel_unique.py

+# Generated by Django 3.2 on 2021-05-15 20:28
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('favicon', '0003_site_manager'),
+    ]
+
+    operations = [
+        migrations.AddConstraint(
+            model_name='faviconimg',
+            constraint=models.UniqueConstraint(fields=('faviconFK', 'size', 'rel'), name='favicon_size_rel_unique'),
+        ),
+    ]

favicon/models.py

 from io import BytesIO
+import hashlib
+import json
 import sys
 
 from PIL import Image
 from django.conf import settings
+from django.core.cache import cache
 from django.core.files.storage import default_storage as storage
 from django.core.files.uploadedfile import InMemoryUploadedFile
 from django.db import models
-from django.db.models import signals
+from django.db.models import Q, signals
 
 use_sites = hasattr(settings, "SITE_ID")
 
@@ -23,6 +26,10 @@ config = {
 }
 
 config = getattr(settings, 'FAVICON_CONFIG', config)
+if "shortcut icon" not in config or 32 not in config["shortcut icon"]:
+    config.setdefault("shortcut_icon", []).append(32)
+
+config_cache_key = "favicons_" + hashlib.sha1(json.dumps(config, sort_keys=True).encode()).hexdigest()
 
 image_path = getattr(settings, "FAVICON_PATH", "favicon")
 
@@ -53,12 +60,45 @@ class Favicon(models.Model):
         verbose_name = 'Favicon'
         verbose_name_plural = 'Favicons'
 
-    def get_favicons(self):
-        favicons = []
+    def get_favicons(self, update=False, config_override=None):
+        """
+        Get all combinations of favicons as configured, creating mising ones.
+
+        Pass update=True to force re-generation of existing icons.
+        """
+        # Use default config by default
+        if config_override is None:
+            config_override = config
+        # Get all combinations of favicon rels and sizes from config
+        query = Q()
+        for rel in config_override:
+            for size in config_override[rel]:
+                query |= Q(rel=rel, size=size)
+
+        # Get all existing favicons
+        favicons = FaviconImg.objects.filter(faviconFK=self).filter(query)
+
+        # Delete all favicon images to update all
+        if update:
+            favicons.delete()
+            favicons = FaviconImg.objects.none()
+            found = []
+        else:
+            favicons = favicons.all()
+            found = [(f.rel, f.size) for f in favicons]
+
+        # Check whether favicons are missing
+        new_favicons = []
         for rel in config:
             for size in config[rel]:
-                favicons.append(self.get_favicon(size, rel))
-        return favicons
+                if not (rel, size) in found:
+                    fav = FaviconImg(faviconFK=self, size=size, rel=rel)
+                    fav.generate_image()
+                    new_favicons.append(fav)
+        if new_favicons:
+            FaviconImg.objects.bulk_create(new_favicons, ignore_conflicts=True)
+                
+        return list(favicons) + new_favicons
 
     def __str__(self):
         return self.faviconImage.name
@@ -69,45 +109,24 @@ class Favicon(models.Model):
     def del_image(self):
         self.faviconImage.delete()
 
-    def get_favicon(self, size, rel, update=False):
-        """
-        get or create a favicon for size, rel(attr) and uploaded favicon
-        optional:
-            update=True
-        """
-        fav, _ = FaviconImg.objects.get_or_create(
-            faviconFK=self, size=size, rel=rel)
-        if update and fav.faviconImage:
-            fav.del_image()
-        if self.faviconImage and not fav.faviconImage:
-            tmp = Image.open(storage.open(self.faviconImage.name))
-            tmp.thumbnail((size, size), Image.ANTIALIAS)
-
-            tmp_io = BytesIO()
-            tmp.save(tmp_io, format='PNG')
-            tmp_file = InMemoryUploadedFile(tmp_io, None, f"fav-{size}s.png", 'image/png', sys.getsizeof(tmp_io), None)
-
-            fav.faviconImage = tmp_file
-            fav.save()
-        return fav
+    def as_html(self, update=False):
+        """Return <link> html tags for this favicon set."""
+        html = ''
+        for favicon in self.get_favicons(update=update):
+            html += favicon.as_html()
+        return html
 
     def save(self, *args, **kwargs):
-        update = False
-
         if self.isFavicon:
-            for n in Favicon.on_site.exclude(pk=self.pk):
-                n.isFavicon = False
-                n.save()
+            Favicon.on_site.exclude(pk=self.pk).update(isFavicon=False)
 
         super(Favicon, self).save(*args, **kwargs)
 
-        if self.faviconImage:
-            for rel in config:
-                for size in config[rel]:
-                    self.get_favicon(size=size, rel=rel, update=update)
+        cache.delete(config_cache_key)
 
-        # make sure default favicon is set
-        self.get_favicon(size=32, rel='shortcut icon')
+        if self.faviconImage:
+            html = self.as_html(update=True)
+            cache.set(config_cache_key, html, timeout=None)
 
 
 class FaviconImg(models.Model):
@@ -116,9 +135,26 @@ class FaviconImg(models.Model):
     rel = models.CharField(max_length=250, null=True)
     faviconImage = models.ImageField(upload_to=image_path)
 
+    def as_html(self):
+        """Return a <link> tag forthis favicon image."""
+        return f'<link rel="{self.rel}" sizes="{self.size}x{self.size}" href="{self.faviconImage.url}"/>'
+
+    def generate_image(self):
+        tmp = Image.open(storage.open(self.faviconFK.faviconImage.name))
+        tmp.thumbnail((self.size, self.size), Image.ANTIALIAS)
+
+        tmp_io = BytesIO()
+        tmp.save(tmp_io, format='PNG')
+        tmp_file = InMemoryUploadedFile(tmp_io, None, f"fav-{self.size}s.png", 'image/png', sys.getsizeof(tmp_io), None)
+
+        self.faviconImage = tmp_file
+
     def del_image(self):
         self.faviconImage.delete()
 
+    class Meta:
+        constraints = [models.UniqueConstraint(fields=["faviconFK", "size", "rel"], name="favicon_size_rel_unique")]
+
 
 signals.pre_delete.connect(pre_delete_image, sender=Favicon)
 signals.pre_delete.connect(pre_delete_image, sender=FaviconImg)

favicon/templatetags/favtags.py

 from django import template
+from django.core.cache import cache
 from django.utils.safestring import mark_safe
 
-from favicon.models import Favicon, config
+from favicon.models import Favicon, config_cache_key
 
 register = template.Library()
 
@@ -16,17 +17,15 @@ def place_favicon(context):
         {% place_favicon %}
 
     """
+
+    html = cache.get(config_cache_key)
+    if html:
+        return mark_safe(html)
+
     fav = Favicon.on_site.filter(isFavicon=True).first()
     if not fav:
         return mark_safe('<!-- no favicon -->')
-    html = ''
-    for rel in config:
-        for size in sorted(config[rel], reverse=True):
-            n = fav.get_favicon(size=size, rel=rel)
-            html += f'<link rel="{n.rel}" sizes="{n.size}x{n.size}" href="{n.faviconImage.url}"/>'
-
-    default_fav = fav.get_favicon(size=32, rel='shortcut icon')
-    html += f'<link rel="{default_fav.rel}" sizes="{default_fav.size}x{default_fav.size}"\
-     href="{default_fav.faviconImage.url}"/>'
+    html = fav.as_html()
 
+    cache.set(config_cache_key, html, timeout=None)
     return mark_safe(html)