Enhance OpenAPI schema customization for improved Swagger UI file upload support

app.py

@@ -1,4 +1,5 @@
 from fastapi import FastAPI
+from fastapi.openapi.utils import get_openapi
 from fastapi.middleware.cors import CORSMiddleware
 from contextlib import asynccontextmanager
 from API.core.config import settings
@@ -38,6 +39,7 @@ def create_app() -> FastAPI:
         version="1.0.0",
         lifespan=lifespan,
         docs_url="/",
+        openapi_version="3.0.2",
     )
 
     # Setup standard CORS middleware to allow cross-origin requests
@@ -52,6 +54,33 @@ def create_app() -> FastAPI:
     # Include routers
     app.include_router(api_router, prefix="/api/v1")
 
+    def custom_openapi():
+        if app.openapi_schema:
+            return app.openapi_schema
+        openapi_schema = get_openapi(
+            title=app.title,
+            version=app.version,
+            description=app.description,
+            routes=app.routes,
+        )
+        # Fix for Swagger UI not showing file upload buttons in some configurations
+        try:
+            batch_files_prop = openapi_schema["components"]["schemas"]["Body_predict_batch_api_v1_predict_batch_post"]["properties"]["files"]
+            batch_files_prop["items"]["format"] = "binary"
+        except KeyError:
+            pass
+            
+        try:
+            single_file_prop = openapi_schema["components"]["schemas"]["Body_predict_image_api_v1_predict_post"]["properties"]["file"]
+            single_file_prop["format"] = "binary"
+        except KeyError:
+            pass
+            
+        app.openapi_schema = openapi_schema
+        return app.openapi_schema
+
+    app.openapi = custom_openapi
+
     return app
 
 app = create_app()