Fix cURL error 77 on Windows (#647)

Author: ewnn112

curl_cffi/curl.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import re
+import locale
 import struct
 import sys
 import warnings
@@ -256,7 +257,34 @@ def setopt(self, option: CurlOpt, value: Any) -> int:
             lib._curl_easy_setopt(self._curl, CurlOpt.DEBUGFUNCTION, lib.debug_function)
             option = CurlOpt.DEBUGDATA
         elif value_type == "char*":
-            c_value = value.encode() if isinstance(value, str) else value
+            if isinstance(value, str):
+                # Windows/libcurl expects ANSI code page for file paths (char*).
+                # Non-ASCII paths encoded as UTF-8 can trigger ErrCode 77.
+                # Encode file-path-like options using the system encoding on Windows.
+                filepath_opts = {
+                    CurlOpt.CAINFO,
+                    CurlOpt.CAPATH,
+                    CurlOpt.PROXY_CAINFO,
+                    CurlOpt.PROXY_CAPATH,
+                    CurlOpt.SSLCERT,
+                    CurlOpt.SSLKEY,
+                    CurlOpt.CRLFILE,
+                    CurlOpt.ISSUERCERT,
+                    CurlOpt.SSH_PUBLIC_KEYFILE,
+                    CurlOpt.SSH_PRIVATE_KEYFILE,
+                    CurlOpt.COOKIEFILE,
+                    CurlOpt.COOKIEJAR,
+                    CurlOpt.NETRC_FILE,
+                    CurlOpt.UNIX_SOCKET_PATH,
+                }
+                if sys.platform.startswith("win") and option in filepath_opts:
+                    # Use the process ANSI code page to match what CRT fopen expects.
+                    enc = locale.getpreferredencoding(False)
+                    c_value = value.encode(enc, errors="strict")
+                else:
+                    c_value = value.encode()
+            else:
+                c_value = value
             # Must keep a reference, otherwise may be GCed.
             if option == CurlOpt.POSTFIELDS:
                 self._body_handle = c_value

docs/faq.rst

@@ -70,9 +70,11 @@ The simplest way is to turn off cert verification by ``verify=False``:
 ErrCode: 77, Reason: error setting certificate verify locations
 ------
 
-Install ``curl_cffi`` and its dependencies in a pure-ASCII path, i.e. no Chinese or any
-other characters out of the ASCII table in the path.
-
+On Windows, if your Python environment or CA bundle path contains non-ASCII characters
+(e.g. accents), libcurl may fail to open the CA file when passed as a narrow ``char*``.
+``curl_cffi`` now encodes file-path options (e.g. ``CAINFO``, ``PROXY_CAINFO``,
+``SSLCERT``) using the system's preferred ANSI code page on Windows to ensure correct
+file access. This fixes most occurrences of error 77.
 
 How to use with fiddler/charles to intercept content
 ------