#53 #54 Created CSV Renderer to present serialized data in CSV format.

src/cvservices/renderers.py

@@ -1,3 +1,8 @@
+import csv
+from ctypes import Union
+from io import BytesIO, StringIO
+from typing import Union, Dict, List, KeysView
+
 from rest_framework import renderers
 
 
@@ -10,8 +15,31 @@ def render(self, data, media_type=None, renderer_context=None):
 
 
 class CSVRenderer(renderers.BaseRenderer):
-    media_type = 'text/csv'
-    format = 'csv'
+    media_type: str = 'text/csv'
+    format: str = 'csv'
 
-    def render(self, data, media_type=None, renderer_context=None):
-        return "This is CSV DATA"
+    def render(self, data: Union[Dict, List[Dict]], media_type: str = None, renderer_context=None) -> str:
+        """
+        Receives an already serialized object/list of objects and converts it to a csv file.
+        :param data: An individual or a list of serialized controlled vocabulary objects.
+        :param media_type: The media type of the request.
+        :param renderer_context: The renderer context.
+        :return: A CSV rendition of the serialized controlled vocabulary.
+        """
+        if data is None:
+            return ''
+
+        if not isinstance(data, list):
+            data = [data]
+
+        # Create string buffer to store hold the csv file content
+        csv_buffer: StringIO = StringIO()
+        # Get the fieldnames from the first object in the data
+        fieldnames: KeysView = data[0].keys()
+        # Create a CSV writer with the string buffer
+        csv_writer: csv.DictWriter = csv.DictWriter(csv_buffer, fieldnames=fieldnames)
+        # Write the headers and data to the CSV writer
+        csv_writer.writeheader()
+        csv_writer.writerows(data)
+        # Return the contents of the writer
+        return csv_buffer.getvalue()