fix: make view content disposition headers valid

server.py

@@ -47,6 +47,7 @@ from app.node_replace_manager import NodeReplaceManager
 from typing import Optional, Union
 from api_server.routes.internal.internal_routes import InternalRoutes
 from protocol import BinaryEventTypes
+from utils.http_headers import content_disposition_header
 
 # Import cache control middleware
 from middleware.cache_middleware import cache_control
@@ -560,7 +561,7 @@ class PromptServer():
                             buffer.seek(0)
 
                             return web.Response(body=buffer.read(), content_type=f'image/{image_format}',
-                                                headers={"Content-Disposition": f"filename=\"{filename}\""})
+                                                headers={"Content-Disposition": content_disposition_header(filename, "inline")})
 
                     if 'channel' not in request.rel_url.query:
                         channel = 'rgba'
@@ -580,7 +581,7 @@ class PromptServer():
                             buffer.seek(0)
 
                             return web.Response(body=buffer.read(), content_type='image/png',
-                                                headers={"Content-Disposition": f"filename=\"{filename}\""})
+                                                headers={"Content-Disposition": content_disposition_header(filename, "inline")})
 
                     elif channel == 'a':
                         with Image.open(file) as img:
@@ -597,7 +598,7 @@ class PromptServer():
                             alpha_buffer.seek(0)
 
                             return web.Response(body=alpha_buffer.read(), content_type='image/png',
-                                                headers={"Content-Disposition": f"filename=\"{filename}\""})
+                                                headers={"Content-Disposition": content_disposition_header(filename, "inline")})
                     else:
                         # Use the content type from asset resolution if available,
                         # otherwise guess from the filename.
@@ -614,7 +615,7 @@ class PromptServer():
                         return web.FileResponse(
                             file,
                             headers={
-                                "Content-Disposition": f"filename=\"{filename}\"",
+                                "Content-Disposition": content_disposition_header(filename, "inline"),
                                 "Content-Type": content_type
                             }
                         )

tests-unit/prompt_server_test/view_image_header_test.py

@@ -0,0 +1,31 @@
+from email.message import Message
+
+from utils.http_headers import content_disposition_header
+
+
+def test_view_content_disposition_is_valid_inline_filename():
+    header = content_disposition_header("example image.png", "inline")
+
+    message = Message()
+    message["Content-Disposition"] = header
+
+    assert message.get_content_disposition() == "inline"
+    assert message.get_filename() == "example image.png"
+    assert "filename*=UTF-8''example%20image.png" in header
+
+
+def test_view_content_disposition_sanitizes_control_characters():
+    header = content_disposition_header('bad"\r\nname.png', "inline")
+
+    message = Message()
+    message["Content-Disposition"] = header
+
+    assert message.get_content_disposition() == "inline"
+    assert message.get_filename() == "bad__name.png"
+
+
+def test_view_content_disposition_adds_utf8_filename_parameter():
+    header = content_disposition_header("café.png", "inline")
+
+    assert 'filename="caf_.png"' in header
+    assert "filename*=UTF-8''caf%C3%A9.png" in header

utils/http_headers.py

@@ -0,0 +1,21 @@
+import re
+import urllib.parse
+
+
+_CONTROL_CHARS_RE = re.compile(r"[\r\n]+")
+_QUOTED_FILENAME_UNSAFE_RE = re.compile(r'["\\]')
+_NON_ASCII_RE = re.compile(r"[^\x20-\x7E]")
+
+
+def content_disposition_header(filename: str, disposition: str) -> str:
+    if disposition not in {"inline", "attachment"}:
+        raise ValueError(f"Unsupported Content-Disposition type: {disposition}")
+
+    safe_filename = _CONTROL_CHARS_RE.sub("_", filename or "")
+    safe_filename = _QUOTED_FILENAME_UNSAFE_RE.sub("_", safe_filename)
+    fallback_filename = _NON_ASCII_RE.sub("_", safe_filename)
+    encoded_filename = urllib.parse.quote(safe_filename)
+    return (
+        f'{disposition}; filename="{fallback_filename}"; '
+        f"filename*=UTF-8''{encoded_filename}"
+    )