fixed paylaod null issue

apps/emqx_bridge_http/src/emqx_bridge_http_connector.erl

@@ -405,7 +405,7 @@ on_query(
                 reason => Reason,
                 connector => InstId
             }),
-            Result;
+Result;
         _Success ->
             Result
     end.
@@ -703,17 +703,22 @@ process_request(
     }.
 
 render_request_body(undefined, _, Msg) ->
-    encode_payload_with_base64(Msg),
-    emqx_utils_json:encode(Msg);
+    ?SLOG(debug, #{msg => "render_request_body111"}),
+    EncodedMsg = encode_payload_with_base64(Msg),
+    emqx_utils_json:encode(EncodedMsg);
 render_request_body(BodyTks, RenderTmplFunc, Msg) ->
+    ?SLOG(debug, #{msg => "render_request_body222"}),
     MsgWithBase64 = encode_payload_with_base64(Msg),
     RenderTmplFunc(BodyTks, MsgWithBase64).
 
 encode_payload_with_base64(Msg) ->
-    Payload = maps:get(<<"payload">>, Msg, <<>>),
+    Payload = maps:get(payload, Msg, <<>>),
     Base64Payload = base64:encode(Payload),
-    maps:put(<<"base64_payload">>, Base64Payload, Msg).
+    maps:put(payload, Base64Payload, Msg).
 
+% 辅助函数：将二进制数据转换为16进制字符串
+binary_to_hex(Bin) ->
+    lists:flatten([io_lib:format("~2.16.0B", [Byte]) || <<Byte>> <= Bin]).
 render_headers(HeaderTks, RenderTmplFunc, Msg) ->
     lists:map(
         fun({K, V}) ->
@@ -913,4 +918,4 @@ join_paths_test_() ->
         ?_assertEqual("abc///cde/", join_paths("abc//", "//cde/"))
     ].
 
--endif.
+-endif.