fix: handle urllib3-future 4-element socket options in SSRF-safe web loader (#26796)

_ssrf_safe_new_conn unpacks each entry of self.socket_options straight into socket.setsockopt(), which accepts exactly 3 positional arguments. urllib3-future, a drop-in fork that shadows the urllib3 package whenever it is installed (for example as a dependency of niquests pulled in through a tool or function's requirements), declares its default socket options with a per-protocol 4th element: [(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1, "tcp")]. Its own _set_socket_options() strips that element before calling setsockopt(), but our override does not, so with urllib3-future present every synchronous web fetch (fetch_url, web search loading) fails on connect with "TypeError: setsockopt() takes exactly 3 arguments (4 given)" and returns empty content.

Mirror urllib3-future's handling in the override: for 4-element options whose last element is a protocol string, apply "tcp" options truncated to the first 3 elements and skip "udp" options (all sockets created here are SOCK_STREAM). Plain 3-element options, and any other shapes stock urllib3 would accept, are passed through unchanged, so behavior with stock urllib3 (which only ever uses 3-element tuples) is identical.

Verified locally: with urllib3-future installed the loader previously raised the TypeError on every URL and now fetches successfully; with stock urllib3 2.3.0 and 2.7.0 fetches behave the same before and after.

Note: #26015 reported this same crash but attributed it to stock urllib3 2.x, which only uses 3-element tuples; the 4-element form comes from urllib3-future shadowing urllib3.

Fixes #26791

backend/open_webui/retrieval/web/utils.py

@@ -158,6 +158,11 @@ def _ssrf_safe_new_conn(self):
             if getattr(self, 'source_address', None):
                 sock.bind(self.source_address)
             for opt in getattr(self, 'socket_options', None) or ():
+                if len(opt) == 4 and isinstance(opt[3], str):
+                    # urllib3-future per-protocol form: (level, optname, value, "tcp"/"udp")
+                    if opt[3].lower() == 'tcp':
+                        sock.setsockopt(*opt[:3])
+                    continue
                 sock.setsockopt(*opt)
             sock.connect(sa)
             return sock