Python Win32 APIでHTTP通信 #Python

Python Win32 APIでウインドウを前面に出す
 Python Win32 APIでウインドウメッセージ

Win32 APIを使ってHTTP通信をやってみます。WinINetというライブラリを使います。

from ctypes import *

InternetOpen = windll.wininet.InternetOpenW
InternetConnect = windll.wininet.InternetConnectW
HttpOpenRequest = windll.wininet.HttpOpenRequestW
HttpSendRequest = windll.wininet.HttpSendRequestW
InternetReadFile = windll.wininet.InternetReadFile
InternetCloseHandle = windll.wininet.InternetCloseHandle
GetLastError = windll.kernel32.GetLastError

ドキュメント(InternetOpenW)を見ると、下の方にDLL Wininet.dllと書かれています。

これより、モジュールのパスは(user32ではなく)windll.wininetになります。

INTERNET_OPEN_TYPE_PRECONFIG = 0

lpszAgent = "test" # ユーザーエージェント(適当)
hInet = InternetOpen(lpszAgent, INTERNET_OPEN_TYPE_PRECONFIG, None, None, 0)
if hInet == 0:
    raise Exception

INTERNET_OPEN_TYPE_PRECONFIG - レジストリから何か設定を読み込むみたいです。

詳しい意味や他のパラメータなど、ドキュメントにすべて書かれています。ただ、どれにすればいいかは試行錯誤です。また、InternetOpenAなど～Aでは通らなかったので、すべて～Wにしています。
(C言語では～Aでも通るのに)

InternetOpenとInternetConnectで初期化、これは最初に一度だけやればよいです。
HttpOpenRequest,HttpSendRequestで送信して、InternetReadFileで応答を(バイト配列で)受信します。

import sys
from ctypes import *

InternetOpen = windll.wininet.InternetOpenW
InternetConnect = windll.wininet.InternetConnectW
InternetCloseHandle = windll.wininet.InternetCloseHandle
HttpOpenRequest = windll.wininet.HttpOpenRequestW
HttpSendRequest = windll.wininet.HttpSendRequestW
InternetReadFile = windll.wininet.InternetReadFile
GetLastError = windll.kernel32.GetLastError

INTERNET_OPEN_TYPE_PRECONFIG = 0
INTERNET_SERVICE_HTTP = 3
INTERNET_DEFAULT_HTTP_PORT = 80

try:
    lpszAgent = "test"
    hInet = InternetOpen(lpszAgent, INTERNET_OPEN_TYPE_PRECONFIG, None, None, 0)
    if hInet == 0:
        raise Exception

    lpszServerName = "docs.microsoft.com"
    hConnect = InternetConnect(hInet, lpszServerName, INTERNET_DEFAULT_HTTP_PORT, None, None, INTERNET_SERVICE_HTTP, 0, None)
    if hConnect == 0:
        raise Exception

    lpszObjectName = "en-us/windows/win32/api/wininet/nf-wininet-internetopenw"
    hRequest = HttpOpenRequest(hConnect, "GET", lpszObjectName, None, None, None, 0, None)
    if hRequest == 0:
        raise Exception

    lpszHeaders = "Content-Type: application/x-www-form-urlencoded"
    ret = HttpSendRequest(hRequest, lpszHeaders, -1, None, 0)
    if ret == 0:
        raise Exception

    dwRead = c_long(1)
    while dwRead.value > 0:
        lpBuffer = create_string_buffer(1024)
        ret = InternetReadFile(hRequest, lpBuffer, 1024, pointer(dwRead))
        if ret == 0:
            raise Exception
        sys.stdout.buffer.write(lpBuffer.value) # 応答を出力

except Exception as e:
    print(GetLastError())
    raise e

finally:
    if hRequest != 0:
        InternetCloseHandle(hRequest)
    if hConnect != 0:
        InternetCloseHandle(hConnect)
    if hInet != 0:
        InternetCloseHandle(hInet)

実行結果

<!DOCTYPE html>
...(略)...
    <div id="action-panel" role="region" aria-label="Action Panel" class="action-panel has-default-focus" tabindex="-1"></div>
</body>
</html>

参考までに、対応するC言語のソース
gcc .\wininet_test.c -lWininet
(Mingw-w64で確認)

wininet_test.c

#include <windows.h>
#include <wininet.h>
#include <stdio.h>

int main(void)
{
    char *lpszAgent = "test";
    HINTERNET hInet = InternetOpenA(lpszAgent, INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);
    if (hInet == NULL)
    {
        printf("InternetOpenA error %d\n", GetLastError());
        goto finally;
    }

    char *lpszServerName = "docs.microsoft.com";
    HINTERNET hConnect = InternetConnectA(hInet, lpszServerName, INTERNET_DEFAULT_HTTP_PORT, NULL, NULL, INTERNET_SERVICE_HTTP, 0, (DWORD_PTR)NULL);
    if (hConnect == NULL)
    {
        printf("InternetConnectA error %d\n", GetLastError());
        goto finally;
    }

    char *lpszObjectName = "en-us/windows/win32/api/wininet/nf-wininet-internetopenw";
    HINTERNET hRequest = HttpOpenRequestA(hConnect, "GET", lpszObjectName, NULL, NULL, NULL, 0, (DWORD_PTR)NULL);
    if (hRequest == NULL)
    {
        printf("HttpOpenRequestA error %d\n", GetLastError());
        goto finally;
    }

    char *lpszHeaders = "Content-Type: application/x-www-form-urlencoded";
    BOOL bRet = HttpSendRequestA(hRequest, lpszHeaders, -1, NULL, 0);
    if (bRet == FALSE)
    {
        printf("HttpSendRequestA error %d\n", GetLastError());
        goto finally;
    }

    char buf[1024] = {0};
    DWORD dwRead = 0;
    do
    {
        bRet = InternetReadFile(hRequest, buf, 1023, &dwRead);
        if (bRet == FALSE)
        {
            printf("InternetReadFile error %d\n", GetLastError());
            goto finally;
        }

        buf[dwRead] = 0; // ヌル終端
        printf(buf);
    } while (dwRead > 0);

finally:
    if (hRequest != NULL) InternetCloseHandle(hRequest);
    if (hConnect != NULL) InternetCloseHandle(hConnect);
    if (hInet != NULL) InternetCloseHandle(hInet);

    return 0;
}