Refactor REST API serializers to avoid circular imports

netbox/dcim/api/serializers_/cables.py

@@ -0,0 +1,127 @@
+from django.contrib.contenttypes.models import ContentType
+from drf_spectacular.types import OpenApiTypes
+from drf_spectacular.utils import extend_schema_field
+from rest_framework import serializers
+
+from dcim.choices import *
+from dcim.constants import *
+from dcim.models import Cable, CablePath, CableTermination
+from netbox.api.fields import ChoiceField, ContentTypeField
+from netbox.api.serializers import GenericObjectSerializer, NetBoxModelSerializer
+from netbox.constants import NESTED_SERIALIZER_PREFIX
+from tenancy.api.serializers_.tenants import TenantSerializer
+from utilities.api import get_serializer_for_model
+
+__all__ = (
+    'CablePathSerializer',
+    'CableSerializer',
+    'CableTerminationSerializer',
+    'CabledObjectSerializer',
+    'TracedCableSerializer',
+)
+
+
+class CableSerializer(NetBoxModelSerializer):
+    url = serializers.HyperlinkedIdentityField(view_name='dcim-api:cable-detail')
+    a_terminations = GenericObjectSerializer(many=True, required=False)
+    b_terminations = GenericObjectSerializer(many=True, required=False)
+    status = ChoiceField(choices=LinkStatusChoices, required=False)
+    tenant = TenantSerializer(nested=True, required=False, allow_null=True)
+    length_unit = ChoiceField(choices=CableLengthUnitChoices, allow_blank=True, required=False, allow_null=True)
+
+    class Meta:
+        model = Cable
+        fields = [
+            'id', 'url', 'display', 'type', 'a_terminations', 'b_terminations', 'status', 'tenant', 'label', 'color',
+            'length', 'length_unit', 'description', 'comments', 'tags', 'custom_fields', 'created', 'last_updated',
+        ]
+        brief_fields = ('id', 'url', 'display', 'label', 'description')
+
+
+class TracedCableSerializer(serializers.ModelSerializer):
+    """
+    Used only while tracing a cable path.
+    """
+    url = serializers.HyperlinkedIdentityField(view_name='dcim-api:cable-detail')
+
+    class Meta:
+        model = Cable
+        fields = [
+            'id', 'url', 'type', 'status', 'label', 'color', 'length', 'length_unit', 'description',
+        ]
+
+
+class CableTerminationSerializer(NetBoxModelSerializer):
+    url = serializers.HyperlinkedIdentityField(view_name='dcim-api:cabletermination-detail')
+    termination_type = ContentTypeField(
+        queryset=ContentType.objects.filter(CABLE_TERMINATION_MODELS)
+    )
+    termination = serializers.SerializerMethodField(read_only=True)
+
+    class Meta:
+        model = CableTermination
+        fields = [
+            'id', 'url', 'display', 'cable', 'cable_end', 'termination_type', 'termination_id', 'termination',
+            'created', 'last_updated',
+        ]
+
+    @extend_schema_field(serializers.JSONField(allow_null=True))
+    def get_termination(self, obj):
+        serializer = get_serializer_for_model(obj.termination, prefix=NESTED_SERIALIZER_PREFIX)
+        context = {'request': self.context['request']}
+        return serializer(obj.termination, context=context).data
+
+
+class CablePathSerializer(serializers.ModelSerializer):
+    path = serializers.SerializerMethodField(read_only=True)
+
+    class Meta:
+        model = CablePath
+        fields = ['id', 'path', 'is_active', 'is_complete', 'is_split']
+
+    @extend_schema_field(serializers.ListField)
+    def get_path(self, obj):
+        ret = []
+        for nodes in obj.path_objects:
+            serializer = get_serializer_for_model(nodes[0], prefix=NESTED_SERIALIZER_PREFIX)
+            context = {'request': self.context['request']}
+            ret.append(serializer(nodes, context=context, many=True).data)
+        return ret
+
+
+class CabledObjectSerializer(serializers.ModelSerializer):
+    cable = CableSerializer(nested=True, read_only=True, allow_null=True)
+    cable_end = serializers.CharField(read_only=True)
+    link_peers_type = serializers.SerializerMethodField(read_only=True)
+    link_peers = serializers.SerializerMethodField(read_only=True)
+    _occupied = serializers.SerializerMethodField(read_only=True)
+
+    @extend_schema_field(OpenApiTypes.STR)
+    def get_link_peers_type(self, obj):
+        """
+        Return the type of the peer link terminations, or None.
+        """
+        if not obj.cable:
+            return None
+
+        if obj.link_peers:
+            return f'{obj.link_peers[0]._meta.app_label}.{obj.link_peers[0]._meta.model_name}'
+
+        return None
+
+    @extend_schema_field(serializers.ListField)
+    def get_link_peers(self, obj):
+        """
+        Return the appropriate serializer for the link termination model.
+        """
+        if not obj.link_peers:
+            return []
+
+        # Return serialized peer termination objects
+        serializer = get_serializer_for_model(obj.link_peers[0], prefix=NESTED_SERIALIZER_PREFIX)
+        context = {'request': self.context['request']}
+        return serializer(obj.link_peers, context=context, many=True).data
+
+    @extend_schema_field(serializers.BooleanField)
+    def get__occupied(self, obj):
+        return obj._occupied