♻️(backend) stylistic and consistency changes

Refactored converter services based on PR #1609 review comments:
- Renamed parameter to `data` across all convert methods for consistency
- Replaced recursive call with explicit sequential calls for readability
- Hardcoded CONVERSION_API_SECURE=True in Production class for security
- Removed unused YdocConverter import from viewsets.py
- Updated tests to match new error message wording

Signed-off-by: Stephan Meijer <me@stephanmeijer.com>

src/backend/core/services/converter_services.py

@@ -25,7 +25,7 @@ class ServiceUnavailableError(ConversionError):
 class ConverterProtocol(typing.Protocol):
     """Protocol for converter classes."""
 
-    def convert(self, text, content_type, accept):
+    def convert(self, data, content_type, accept):
         """Convert content from one format to another."""
 
 
@@ -43,10 +43,11 @@ class Converter:
         """Convert input into other formats using external microservices."""
 
         if content_type == mime_types.DOCX and accept == mime_types.YJS:
-            return self.convert(
-                self.docspec.convert(data, mime_types.DOCX, mime_types.BLOCKNOTE),
-                mime_types.BLOCKNOTE,
-                mime_types.YJS,
+            blocknote_data = self.docspec.convert(
+                data, mime_types.DOCX, mime_types.BLOCKNOTE
+            )
+            return self.ydoc.convert(
+                blocknote_data, mime_types.BLOCKNOTE, mime_types.YJS
             )
 
         return self.ydoc.convert(data, content_type, accept)
@@ -111,16 +112,16 @@ class YdocConverter:
         response.raise_for_status()
         return response
 
-    def convert(self, text, content_type=mime_types.MARKDOWN, accept=mime_types.YJS):
+    def convert(self, data, content_type=mime_types.MARKDOWN, accept=mime_types.YJS):
         """Convert a Markdown text into our internal format using an external microservice."""
 
-        if not text:
-            raise ValidationError("Input text cannot be empty")
+        if not data:
+            raise ValidationError("Input data cannot be empty")
 
         try:
             response = self._request(
                 f"{settings.Y_PROVIDER_API_BASE_URL}{settings.CONVERSION_API_ENDPOINT}/",
-                text,
+                data,
                 content_type,
                 accept,
             )

src/backend/core/tests/test_services_converter_services.py

@@ -22,9 +22,9 @@ def test_auth_header(settings):
 
 
 def test_convert_empty_text():
-    """Should raise ValidationError when text is empty."""
+    """Should raise ValidationError when data is empty."""
     converter = YdocConverter()
-    with pytest.raises(ValidationError, match="Input text cannot be empty"):
+    with pytest.raises(ValidationError, match="Input data cannot be empty"):
         converter.convert("")
 
 
@@ -143,5 +143,5 @@ def test_convert_none_input():
     """Should raise ValidationError when input is None."""
     converter = YdocConverter()
 
-    with pytest.raises(ValidationError, match="Input text cannot be empty"):
+    with pytest.raises(ValidationError, match="Input data cannot be empty"):
         converter.convert(None)

src/backend/impress/settings.py

@@ -1057,6 +1057,9 @@ class Production(Base):
     # Privacy
     SECURE_REFERRER_POLICY = "same-origin"
 
+    # Conversion API: Always verify SSL in production
+    CONVERSION_API_SECURE = True
+
     CACHES = {
         "default": {
             "BACKEND": "django_redis.cache.RedisCache",