From 400ae664bba12a2522ea464e2374dfb0d469344a Mon Sep 17 00:00:00 2001
From: teawoong Kim <116135174+ultramancode@users.noreply.github.com>
Date: Wed, 28 May 2025 18:04:38 +0900
Subject: [PATCH] fix(http): force multipart/form-data even without
 files(#20322) (#20323)

---
 api/core/workflow/nodes/http_request/executor.py         | 9 ++++++++-
 .../nodes/http_request/test_http_request_executor.py     | 4 +++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/api/core/workflow/nodes/http_request/executor.py b/api/core/workflow/nodes/http_request/executor.py
index 2c42f5a1be..e28ac6343b 100644
--- a/api/core/workflow/nodes/http_request/executor.py
+++ b/api/core/workflow/nodes/http_request/executor.py
@@ -235,6 +235,10 @@ class Executor:
                                 files[key].append(file_tuple)
 
                     # convert files to list for httpx request
+                    # If there are no actual files, we still need to force httpx to use `multipart/form-data`.
+                    # This is achieved by inserting a harmless placeholder file that will be ignored by the server.
+                    if not files:
+                        self.files = [("__multipart_placeholder__", ("", b"", "application/octet-stream"))]
                     if files:
                         self.files = []
                         for key, file_tuples in files.items():
@@ -373,7 +377,10 @@ class Executor:
             raw += f"{k}: {v}\r\n"
 
         body_string = ""
-        if self.files:
+        # Only log actual files if present.
+        # '__multipart_placeholder__' is inserted to force multipart encoding but is not a real file.
+        # This prevents logging meaningless placeholder entries.
+        if self.files and not all(f[0] == "__multipart_placeholder__" for f in self.files):
             for key, (filename, content, mime_type) in self.files:
                 body_string += f"--{boundary}\r\n"
                 body_string += f'Content-Disposition: form-data; name="{key}"\r\n\r\n'
diff --git a/api/tests/unit_tests/core/workflow/nodes/http_request/test_http_request_executor.py b/api/tests/unit_tests/core/workflow/nodes/http_request/test_http_request_executor.py
index 58b910e17b..d066fc1e33 100644
--- a/api/tests/unit_tests/core/workflow/nodes/http_request/test_http_request_executor.py
+++ b/api/tests/unit_tests/core/workflow/nodes/http_request/test_http_request_executor.py
@@ -246,7 +246,9 @@ def test_executor_with_form_data():
     assert "multipart/form-data" in executor.headers["Content-Type"]
     assert executor.params == []
     assert executor.json is None
-    assert executor.files is None
+    # '__multipart_placeholder__' is expected when no file inputs exist,
+    # to ensure the request is treated as multipart/form-data by the backend.
+    assert executor.files == [("__multipart_placeholder__", ("", b"", "application/octet-stream"))]
     assert executor.content is None
 
     # Check that the form data is correctly loaded in executor.data