Refactor: move input_text validation to schema level using Pydantic validators

api/routes/forms.py

@@ -11,14 +11,15 @@
 
 @router.post("/fill", response_model=FormFillResponse)
 def fill_form(form: FormFill, db: Session = Depends(get_db)):
-    if not get_template(db, form.template_id):
-        raise AppError("Template not found", status_code=404)
-
     fetched_template = get_template(db, form.template_id)
-
+    if not fetched_template:
+        raise AppError("Template not found", status_code=404)
     controller = Controller()
-    path = controller.fill_form(user_input=form.input_text, fields=fetched_template.fields, pdf_form_path=fetched_template.pdf_path)
-
+    path = controller.fill_form(
+        user_input=form.input_text,
+        fields=fetched_template.fields,
+        pdf_form_path=fetched_template.pdf_path
+    )
     submission = FormSubmission(**form.model_dump(), output_pdf_path=path)
     return create_form(db, submission)
 

api/schemas/forms.py

@@ -1,9 +1,15 @@
-from pydantic import BaseModel
+from pydantic import BaseModel, field_validator
 
 class FormFill(BaseModel):
     template_id: int
     input_text: str
 
+    @field_validator("input_text")
+    def validate_input_text(cls, value):
+        if not value or not value.strip():
+            raise ValueError("Input text cannot be empty")
+        return value
+
 
 class FormFillResponse(BaseModel):
     id: int