Implement natural sorting. (Yay!)

savepointradio/core/utils.py

@@ -1,5 +1,7 @@
 import random
+import re
 import string
+from unicodedata import normalize
 
 from django.core.exceptions import ObjectDoesNotExist
 from django.db import connection
@@ -52,3 +54,23 @@ def set_setting(name, value, setting_type=None):
             error_msg = 'New settings need type (Integer, Float, String, Bool)'
             raise TypeError(error_msg)
     return
+
+
+def naturalize(string):
+    """
+    Return a normalized unicode string, with removed starting articles, for use
+    in natural sorting.
+
+    Code was inspired by 'django-naturalsortfield' from Nathan Reynolds:
+    https://github.com/nathforge/django-naturalsortfield
+    """
+    def naturalize_int_match(match):
+        return '%08d' % (int(match.group(0)),)
+
+    string = normalize('NFKD', string).encode('ascii', 'ignore').decode('ascii')
+    string = string.lower()
+    string = string.strip()
+    string = re.sub(r'^(a|an|the)\s+', '', string)
+    string = re.sub(r'\d+', naturalize_int_match, string)
+
+    return string

savepointradio/radio/admin.py

@@ -15,6 +15,8 @@ class ArtistInline(admin.TabularInline):
 
 @admin.register(Album)
 class AlbumAdmin(admin.ModelAdmin):
+    ordering = ("sorted_title",)
+    
     # Detail List display
     list_display = ('title', '_is_enabled', '_is_published')
     search_fields = ['title']
@@ -48,6 +50,8 @@ class AlbumAdmin(admin.ModelAdmin):
 
 @admin.register(Artist)
 class ArtistAdmin(admin.ModelAdmin):
+    ordering = ("sorted_full_name",)
+    
     # Detail List display
     list_display = ('first_name',
                     'alias',
@@ -85,6 +89,8 @@ class ArtistAdmin(admin.ModelAdmin):
 
 @admin.register(Game)
 class GameAdmin(admin.ModelAdmin):
+    ordering = ("sorted_title",)
+    
     # Detail List display
     list_display = ('title', '_is_enabled', '_is_published')
     search_fields = ['title']
@@ -118,6 +124,8 @@ class GameAdmin(admin.ModelAdmin):
 
 @admin.register(Song)
 class SongAdmin(admin.ModelAdmin):
+    ordering = ("sorted_title",)
+    
     formfield_overrides = {
         models.TextField: {'widget': TextInput(attrs={'size': 160, })},
     }

savepointradio/radio/apps.py

@@ -3,3 +3,6 @@ from django.apps import AppConfig
 
 class RadioConfig(AppConfig):
     name = 'radio'
+
+    def ready(self):
+        from .signals import update_sorted_fields

savepointradio/radio/migrations/0001_initial.py

@@ -1,4 +1,4 @@
-# Generated by Django 2.0 on 2017-12-29 14:36
+# Generated by Django 2.0 on 2018-01-05 19:40
 
 from django.db import migrations, models
 import django.db.models.deletion
@@ -23,6 +23,7 @@ class Migration(migrations.Migration):
                 ('disabled_reason', models.TextField(blank=True, verbose_name='reason for disabling')),
                 ('published_date', models.DateTimeField(blank=True, default=None, null=True, verbose_name='published for listening')),
                 ('title', models.CharField(max_length=255, unique=True, verbose_name='title')),
+                ('sorted_title', models.CharField(db_index=True, editable=False, max_length=255, verbose_name='naturalized title')),
             ],
             options={
                 'abstract': False,
@@ -41,6 +42,7 @@ class Migration(migrations.Migration):
                 ('alias', models.CharField(blank=True, max_length=127, verbose_name='alias')),
                 ('first_name', models.CharField(blank=True, max_length=127, verbose_name='first name')),
                 ('last_name', models.CharField(blank=True, max_length=127, verbose_name='last name')),
+                ('sorted_full_name', models.CharField(db_index=True, editable=False, max_length=255, verbose_name='naturalized full name')),
             ],
             options={
                 'abstract': False,
@@ -57,6 +59,7 @@ class Migration(migrations.Migration):
                 ('disabled_reason', models.TextField(blank=True, verbose_name='reason for disabling')),
                 ('published_date', models.DateTimeField(blank=True, default=None, null=True, verbose_name='published for listening')),
                 ('title', models.CharField(max_length=255, unique=True, verbose_name='title')),
+                ('sorted_title', models.CharField(db_index=True, editable=False, max_length=255, verbose_name='naturalized title')),
             ],
             options={
                 'abstract': False,
@@ -78,6 +81,7 @@ class Migration(migrations.Migration):
                 ('last_played', models.DateTimeField(blank=True, editable=False, null=True, verbose_name='was last played')),
                 ('length', models.DecimalField(blank=True, decimal_places=2, max_digits=8, null=True, verbose_name='song length (in seconds)')),
                 ('path', models.TextField(verbose_name='absolute path to song file')),
+                ('sorted_title', models.CharField(db_index=True, editable=False, max_length=255, verbose_name='naturalized title')),
                 ('album', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='radio.Album')),
                 ('artists', models.ManyToManyField(to='radio.Artist')),
                 ('game', models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.SET_NULL, to='radio.Game')),

savepointradio/radio/models.py

@@ -12,6 +12,11 @@ class Album(Disableable, Publishable, Timestampable, models.Model):
     """
     title = models.CharField(_('title'), max_length=255, unique=True)
 
+    sorted_title = models.CharField(_('naturalized title'),
+                                    db_index=True,
+                                    editable=False,
+                                    max_length=255)
+
     def __str__(self):
         return self.title
 
@@ -24,8 +29,10 @@ class Artist(Disableable, Publishable, Timestampable, models.Model):
     first_name = models.CharField(_('first name'), max_length=127, blank=True)
     last_name = models.CharField(_('last name'), max_length=127, blank=True)
 
-    class Meta:
+    sorted_full_name = models.CharField(_('naturalized full name'),
-        ordering = ('first_name', 'alias',)
+                                        db_index=True,
+                                        editable=False,
+                                        max_length=255)
 
     @property
     def full_name(self):
@@ -49,6 +56,11 @@ class Game(Disableable, Publishable, Timestampable, models.Model):
     """
     title = models.CharField(_('title'), max_length=255, unique=True)
 
+    sorted_title = models.CharField(_('naturalized title'),
+                                    db_index=True,
+                                    editable=False,
+                                    max_length=255)
+
     def __str__(self):
         return self.title
 
@@ -90,6 +102,11 @@ class Song(Disableable, Publishable, Timestampable, models.Model):
                                  blank=True)
     path = models.TextField(_('absolute path to song file'))
 
+    sorted_title = models.CharField(_('naturalized title'),
+                                    db_index=True,
+                                    editable=False,
+                                    max_length=255)
+
     objects = models.Manager()
     music = SongManager()
 

savepointradio/radio/signals.py

@@ -0,0 +1,16 @@
+from django.db.models.signals import pre_save
+from django.dispatch import receiver
+
+from core.utils import naturalize
+from .models import Album, Artist, Game, Song
+
+
+@receiver(pre_save, sender=Album)
+@receiver(pre_save, sender=Artist)
+@receiver(pre_save, sender=Game)
+@receiver(pre_save, sender=Song)
+def update_sorted_fields(sender, instance, **kwargs):
+    if sender == Artist:
+        instance.sorted_full_name = naturalize(getattr(instance, 'full_name'))
+    else:
+        instance.sorted_title = naturalize(getattr(instance, 'title'))