Clean up API codebase by using idiomatic DRF and removing boilerplate

openverse-api/catalog/api/serializers/audio_serializers.py

@@ -1,4 +1,3 @@
-from django.urls import reverse
 from rest_framework import serializers
 
 from catalog.api.controllers.search_controller import get_sources
@@ -96,12 +95,6 @@ class AudioSerializer(MediaSerializer):
     used to generate Swagger documentation.
     """
 
-    thumbnail = serializers.SerializerMethodField(
-        help_text="A direct link to the miniature artwork."
-    )
-    waveform = serializers.SerializerMethodField(
-        help_text='A direct link to the waveform peaks.'
-    )
     audio_set = serializers.PrimaryKeyRelatedField(
         required=False,
         help_text='Reference to set of which this track is a part.',
@@ -135,31 +128,31 @@ class AudioSerializer(MediaSerializer):
     )
 
     # Hyperlinks
+    thumbnail = serializers.HyperlinkedIdentityField(
+        read_only=True,
+        view_name='audio-thumb',
+        lookup_field='identifier',
+        help_text="A direct link to the miniature artwork."
+    )
+    waveform = serializers.HyperlinkedIdentityField(
+        read_only=True,
+        view_name='audio-waveform',
+        lookup_field='identifier',
+        help_text='A direct link to the waveform peaks.'
+    )
     detail_url = serializers.HyperlinkedIdentityField(
         read_only=True,
         view_name='audio-detail',
         lookup_field='identifier',
         help_text="A direct link to the detail view of this audio file."
     )
     related_url = serializers.HyperlinkedIdentityField(
+        read_only=True,
         view_name='audio-related',
         lookup_field='identifier',
-        read_only=True,
         help_text="A link to an endpoint that provides similar audio files."
     )
 
-    def get_thumbnail(self, obj):
-        request = self.context['request']
-        host = request.get_host()
-        path = reverse('audio-thumb', kwargs={'identifier': obj.identifier})
-        return f'https://{host}{path}'
-
-    def get_waveform(self, obj):
-        request = self.context['request']
-        host = request.get_host()
-        path = reverse('audio-waveform', kwargs={'identifier': obj.identifier})
-        return f'https://{host}{path}'
-
 
 class AudioSearchSerializer(MediaSearchSerializer):
     """

openverse-api/catalog/api/serializers/image_serializers.py

@@ -97,9 +97,6 @@ class ImageSerializer(MediaSerializer):
     used to generate Swagger documentation.
     """
 
-    thumbnail = serializers.SerializerMethodField(
-        help_text="A direct link to the miniature image."
-    )
     height = serializers.IntegerField(
         required=False,
         help_text="The height of the image in pixels. Not always available."
@@ -110,6 +107,12 @@ class ImageSerializer(MediaSerializer):
     )
 
     # Hyperlinks
+    thumbnail = serializers.HyperlinkedIdentityField(
+        read_only=True,
+        view_name='image-thumb',
+        lookup_field='identifier',
+        help_text="A direct link to the miniature image."
+    )
     detail_url = serializers.HyperlinkedIdentityField(
         read_only=True,
         view_name='image-detail',
@@ -123,12 +126,6 @@ class ImageSerializer(MediaSerializer):
         help_text="A link to an endpoint that provides similar images."
     )
 
-    def get_thumbnail(self, obj):
-        request = self.context['request']
-        host = request.get_host()
-        path = reverse('image-thumb', kwargs={'identifier': obj.identifier})
-        return f'https://{host}{path}'
-
 
 class ImageSearchSerializer(MediaSearchSerializer):
     """