enhance Curl class to handle None curl cases (#631)

Author: montovaneli

curl_cffi/curl.py

@@ -207,6 +207,8 @@ def setopt(self, option: CurlOpt, value: Any) -> int:
         Returns:
             0 if no error, see ``CurlECode``.
         """
+        if self._curl is None:
+            return 0  # silently ignore if curl handle is None
         input_option = {
             # this should be int in curl, but cffi requires pointer for void*
             # it will be convert back in the glue c code.
@@ -308,18 +310,28 @@ def getinfo(self, option: CurlInfo) -> Union[bytes, int, float, list]:
             0x100000: ffi.string,
             0x200000: int,
             0x300000: float,
+            0x400000: list,
             0x500000: int,
             0x600000: int,
         }
-        c_value = ffi.new(ret_option[option & 0xF00000])
+
+        option_type = option & 0xF00000
+
+        if self._curl is None:
+            if option_type == 0x100000:
+                return b""
+            return ret_cast_option[option_type]()
+
+        c_value = ffi.new(ret_option[option_type])
         ret = lib.curl_easy_getinfo(self._curl, option, c_value)
         self._check_error(ret, "getinfo", option)
         # cookielist and ssl_engines starts with 0x400000, see also: const.py
-        if option & 0xF00000 == 0x400000:
+        if option_type == 0x400000:
             return slist_to_list(c_value[0])
         if c_value[0] == ffi.NULL:
             return b""
-        return ret_cast_option[option & 0xF00000](c_value[0])
+
+        return ret_cast_option[option_type](c_value[0])
 
     def version(self) -> bytes:
         """Get the underlying libcurl version."""
@@ -335,6 +347,8 @@ def impersonate(self, target: str, default_headers: bool = True) -> int:
         Returns:
             0 if no error.
         """
+        if self._curl is None:
+            return 0  # silently ignore if curl handle is None
         return lib.curl_easy_impersonate(
             self._curl, target.encode(), int(default_headers)
         )
@@ -356,6 +370,9 @@ def perform(self, clear_headers: bool = True, clear_resolve: bool = True) -> Non
         Raises:
             CurlError: if the perform was not successful.
         """
+        if self._curl is None:
+            raise CurlError("Cannot perform request on closed handle.")
+
         # make sure we set a cacert store
         self._ensure_cacert()
 
@@ -369,12 +386,14 @@ def perform(self, clear_headers: bool = True, clear_resolve: bool = True) -> Non
             self.clean_handles_and_buffers(clear_headers, clear_resolve)
 
     def upkeep(self) -> int:
+        if self._curl is None:
+            return 0  # silently ignore if curl handle is None
         return lib.curl_easy_upkeep(self._curl)
 
     def clean_handles_and_buffers(
         self, clear_headers: bool = True, clear_resolve: bool = True
     ) -> None:
-        """Clean up handles and buffers after ``perform`` and ``close``, 
+        """Clean up handles and buffers after ``perform`` and ``close``,
         called at the end of ``perform`` and ``close``."""
         self._write_handle = None
         self._header_handle = None
@@ -400,6 +419,8 @@ def duphandle(self) -> Curl:
 
         This is not a full copy of entire curl object in python. For example, headers
         handle is not copied, you have to set them again."""
+        if self._curl is None:
+            raise CurlError("Cannot duplicate closed handle.")
         new_handle = lib.curl_easy_duphandle(self._curl)
         c = Curl(cacert=self._cacert, debug=self._debug, handle=new_handle)
         return c
@@ -478,6 +499,9 @@ def ws_recv(self, n: int = 1024) -> tuple[bytes, CurlWsFrame]:
         Raises:
             CurlError: if failed.
         """
+        if self._curl is None:
+            raise CurlError("Cannot receive websocket data on closed handle.")
+
         buffer = ffi.new("char[]", n)
         n_recv = ffi.new("size_t *")
         p_frame = ffi.new("struct curl_ws_frame **")
@@ -503,6 +527,9 @@ def ws_send(self, payload: bytes, flags: CurlWsFlag = CurlWsFlag.BINARY) -> int:
         Raises:
             CurlError: if failed.
         """
+        if self._curl is None:
+            raise CurlError("Cannot send websocket data on closed handle.")
+
         n_sent = ffi.new("size_t *")
         buffer = ffi.from_buffer(payload)
         ret = lib.curl_ws_send(self._curl, buffer, len(payload), n_sent, 0, flags)