feat: show content by accepted type

lnbits/middleware.py

@@ -1,5 +1,5 @@
 from http import HTTPStatus
-from typing import List, Tuple
+from typing import Any, List, Tuple, Union
 from urllib.parse import parse_qs
 
 from fastapi.responses import HTMLResponse, JSONResponse
@@ -29,23 +29,19 @@ class InstalledExtensionMiddleware:
             _, path_name = path_elements
             path_type = None
 
+        headers = scope.get("headers", [])
+
         # block path for all users if the extension is disabled
         if path_name in settings.lnbits_deactivated_extensions:
-            response = JSONResponse(
+            response = self._response_by_accepted_type(
-                status_code=HTTPStatus.NOT_FOUND,
+                headers, f"Extension '{path_name}' disabled", HTTPStatus.NOT_FOUND
-                content={"detail": f"Extension '{path_name}' disabled"},
             )
             await response(scope, receive, send)
             return
 
         if not self._user_allowed_to_extension(path_name, scope):
-            response = HTMLResponse(
+            response = self._response_by_accepted_type(
-                status_code=HTTPStatus.FORBIDDEN,
+                headers, "User not authorized.", HTTPStatus.FORBIDDEN
-                content=template_renderer()
-                .TemplateResponse(
-                    "error.html", {"request": {}, "err": "User not authorized."}
-                )
-                .body,
             )
             await response(scope, receive, send)
             return
@@ -81,6 +77,31 @@ class InstalledExtensionMiddleware:
 
         return False
 
+    def _response_by_accepted_type(
+        self, headers: List[Any], msg: str, status_code: HTTPStatus
+    ) -> Union[HTMLResponse, JSONResponse]:
+        accept_header: str = next(
+            (
+                h[1].decode("UTF-8")
+                for h in headers
+                if len(h) >= 2 and h[0].decode("UTF-8") == "accept"
+            ),
+            "",
+        )
+
+        if "text/html" in [a for a in accept_header.split(",")]:
+            return HTMLResponse(
+                status_code=status_code,
+                content=template_renderer()
+                .TemplateResponse("error.html", {"request": {}, "err": msg})
+                .body,
+            )
+
+        return JSONResponse(
+            status_code=status_code,
+            content={"detail": msg},
+        )
+
 
 class ExtensionsRedirectMiddleware:
     # Extensions are allowed to specify redirect paths.