Pre-generate HTML on save

favicon/models.py

@@ -106,6 +106,13 @@ class Favicon(models.Model):
     def del_image(self):
         self.faviconImage.delete()
 
+    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
 
@@ -114,11 +121,12 @@ class Favicon(models.Model):
 
         super(Favicon, self).save(*args, **kwargs)
 
-        if self.faviconImage:
-            self.get_favicons(update=update)
-
         cache.delete(config_cache_key)
 
+        if self.faviconImage:
+            html = self.get_favicons(update=update)
+            cache.set(config_cache_key, html, timeout=None)
+
 
 class FaviconImg(models.Model):
     faviconFK = models.ForeignKey(Favicon, on_delete=models.CASCADE)
@@ -126,6 +134,10 @@ 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)

favicon/templatetags/favtags.py

@@ -25,9 +25,8 @@ def place_favicon(context):
     fav = Favicon.on_site.filter(isFavicon=True).first()
     if not fav:
         return mark_safe('<!-- no favicon -->')
-    html = ''
-    for n in fav.get_favicons():
-        html += f'<link rel="{n.rel}" sizes="{n.size}x{n.size}" href="{n.faviconImage.url}"/>'
+
+    html = fav.as_html()
 
     cache.set(config_cache_key, html, timeout=None)
     return mark_safe(html)