How to tell WinINet to use IE's proxy server credentials

Question

In internet explorer i can set the proxy server. Then, when accessing the internet IE will prompt me for proxy credentials and optionally save them. New instances of IE pick up the credentials.

I can also see the credentials are saved in the Credentials Manager, as a Generic Credential. The name follows a naming convention like Microsoft_WinInet_[proxyserver:port]/[proxyserver.acme.com].

My app uses WinINet. We are currently setting the credentials via InternetSetOption with INTERNET_OPTION_PROXY_USERNAME and INTERNET_OPTION_PROXY_PASSWORD.

But instead I want to tell WinINet to use IE's (or the Credentials Manager) credentials for the current user.

score 2 · Answer 1 · answered Mar 14 '12 at 17:40

The way to have WinINet use credentials manager credentials is to use the InternetErrorDlg function, like so:

retry:
  BOOL fRet = ::HttpSendRequest(hRequest, NULL, 0, NULL, 0);
  DWORD dwError = ::GetLastError();
  DWORD statusCode(0);
  DWORD statusLen = sizeof(DWORD);  
  DWORD headerIndex = 0;
  ::HttpQueryInfo(hRequest, HTTP_QUERY_FLAG_NUMBER | HTTP_QUERY_STATUS_CODE, 
                  &statusCode, &statusLen, &headerIndex);

  if (statusCode == HTTP_STATUS_PROXY_AUTH_REQ) 
  {
    DWORD dwFlags = FLAGS_ERROR_UI_FILTER_FOR_ERRORS |
                    FLAGS_ERROR_UI_FLAGS_CHANGE_OPTIONS | 
                    FLAGS_ERROR_UI_FLAGS_GENERATE_DATA;
    DWORD res =::InternetErrorDlg(GetDesktopWindow(), hRequest, 
                                  ERROR_INTERNET_INCORRECT_PASSWORD, dwFlags, NULL);
    if (res == ERROR_INTERNET_FORCE_RETRY)
      goto retry;
    else
      return false;
  }

InternetErrorDlg will return ERROR_INTERNET_FORCE_RETRY if it succeeded in getting credentials (from the CM or by prompting the user).

The FLAGS_ERROR_UI_FLAGS_NO_UI flag (not used above) can be used to avoid showing the dialog that prompts the user for credentials.

Julio

score 1 · Answer 2 · edited Apr 12 '13 at 09:09

1

Initialize the use of WinINet functions with predefined proxy parameters from IE like this

HINTERNET hOpen = NULL;

hOpen = InternetOpen(L"XXX", INTERNET_OPEN_TYPE_PRECONFIG, NULL, NULL, 0);

...

edited Apr 12 '13 at 09:09

answered Apr 12 '13 at 08:46

Nikola

11
1

How to tell WinINet to use IE's proxy server credentials

2 Answers2