[FEAT] Add Django command to selectively load fixtures

Only loads data if object isn't a BootstrapTheme that already exists

breccia_mapper/management/commands/selectiveloaddata.py

@@ -0,0 +1,44 @@
+import json
+import os
+
+from django.core.management.commands import loaddata
+
+from bootstrap_customizer.models import BootstrapTheme
+
+
+def should_add_record(record):
+    if record['model'] != 'bootstrap_customizer.bootstraptheme':
+        return True
+
+    return not BootstrapTheme.objects.filter(
+        pk=record['pk'],
+    ).exists()
+
+
+class Command(loaddata.Command):
+    def handle(self, *args, **options):
+        args = list(args)
+
+        # Read the original JSON file
+        file_name = args[0]
+        with open(file_name) as json_file:
+            json_list = json.load(json_file)
+
+        # Filter out records that already exists
+        json_list_filtered = list(filter(should_add_record, json_list))
+        if not json_list_filtered:
+            print("All data are already previously loaded")
+            return
+
+        # Write the updated JSON file
+        file_dir_and_name, file_ext = os.path.splitext(file_name)
+        file_name_temp = f"{file_dir_and_name}_temp{file_ext}"
+        with open(file_name_temp, 'w') as json_file_temp:
+            json.dump(json_list_filtered, json_file_temp)
+
+        # Pass the request to the actual loaddata (parent functionality)
+        args[0] = file_name_temp
+        super().handle(*args, **options)
+
+        # You can choose to not delete the file so that you can see what was added to your records
+        os.remove(file_name_temp)