From 8b89447549df36aa25786c0f2ce16021919b3604 Mon Sep 17 00:00:00 2001
From: JimintheBox <gjwlals111@gmail.com>
Date: Thu, 27 Mar 2025 11:47:35 +0900
Subject: [PATCH] Fix Custom Tool File Upload: Resolve Multiple Files
 Recognition and Multipart Boundary Issues (#14014)

Co-authored-by: crazywoola <427733928@qq.com>
---
 api/core/tools/custom_tool/tool.py    | 14 +++++++++++++-
 api/core/tools/utils/parser.py        |  3 +++
 docker/ssrf_proxy/squid.conf.template |  3 +++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/api/core/tools/custom_tool/tool.py b/api/core/tools/custom_tool/tool.py
index 5003c1dd51..b1121fceec 100644
--- a/api/core/tools/custom_tool/tool.py
+++ b/api/core/tools/custom_tool/tool.py
@@ -195,7 +195,12 @@ class ApiTool(Tool):
                     properties = body_schema.get("properties", {})
                     for name, property in properties.items():
                         if name in parameters:
-                            if property.get("format") == "binary":
+                            # multiple file upload: if the type is array and the items have format as binary
+                            if property.get("type") == "array" and property.get("items", {}).get("format") == "binary":
+                                # parameters[name] should be a list of file objects.
+                                for f in parameters[name]:
+                                    files.append((name, (f.filename, download(f), f.mime_type)))
+                            elif property.get("format") == "binary":
                                 f = parameters[name]
                                 files.append((name, (f.filename, download(f), f.mime_type)))
                             elif "$ref" in property:
@@ -226,6 +231,13 @@ class ApiTool(Tool):
             else:
                 body = body
 
+        # if there is a file upload, remove the Content-Type header
+        # so that httpx can automatically generate the boundary header required for multipart/form-data.
+        # issue: https://github.com/langgenius/dify/issues/13684
+        # reference: https://stackoverflow.com/questions/39280438/fetch-missing-boundary-in-multipart-form-data-post
+        if files:
+            headers.pop("Content-Type", None)
+
         if method in {
             "get",
             "head",
diff --git a/api/core/tools/utils/parser.py b/api/core/tools/utils/parser.py
index c69fc1f825..120c1fcfea 100644
--- a/api/core/tools/utils/parser.py
+++ b/api/core/tools/utils/parser.py
@@ -186,6 +186,9 @@ class ApiBasedToolSchemaParser:
             return ToolParameter.ToolParameterType.BOOLEAN
         elif typ == "string":
             return ToolParameter.ToolParameterType.STRING
+        elif typ == "array":
+            items = parameter.get("items") or parameter.get("schema", {}).get("items")
+            return ToolParameter.ToolParameterType.FILES if items and items.get("format") == "binary" else None
         else:
             return None
 
diff --git a/docker/ssrf_proxy/squid.conf.template b/docker/ssrf_proxy/squid.conf.template
index 7e85e84a6f..c74c1fb67b 100644
--- a/docker/ssrf_proxy/squid.conf.template
+++ b/docker/ssrf_proxy/squid.conf.template
@@ -51,3 +51,6 @@ http_port ${REVERSE_PROXY_PORT} accel vhost
 cache_peer ${SANDBOX_HOST} parent ${SANDBOX_PORT} 0 no-query originserver
 acl src_all src all
 http_access allow src_all
+
+# Unless the option's size is increased, an error will occur when uploading more than two files.
+client_request_buffer_max_size 100 MB
\ No newline at end of file