I’ve previously made a WebService that encapsulates calls to a Lotus Notes database. From this database I extract meeting rooms and today’s meetings for each room. This information is used by others to show on monitors beside each meeting room. They just call my service, and get their xml back. All the “ugly” communication with Lotus Notes is completely hidden from them.
The service hasn’t been all that stable, not my service fault though, but since the service hides all the Notes problems – it is easy to blame the messenger. I was not initially allowed to read directly from the master database file (database.nsf). That is placed behind firewalls on another server. The workaround for this was setting up a replication. This worked very well, as long as someone is logged on the console, on the server. See the problem… Sometimes the service shows old data that is displayed beside the meeting rooms. Causing confusion about who has reserved the room or not. I’m not a Notes-kind of guy, so this might have been set up more robust or elegant.
But now I am given a hole in the firewall, to a network file share, directly to the master database file. Which in Lotus Notes is an nsf file. The service can now access the file, no longer to the replica C:\Program Files\IBM\Lotus\Domino\Data\FooCopy.nsf, but directly to the \\fooserver\notes\Foo.nsf. The file share is protected with access only to a given user. Accessing UNC Path is supported with the Lotus Notes ODBC Driver. But I ran into some problems with the UNC Path logon.
Previously I’ve used impersonation when accessing the UNC Path. So I tried this first. Impersonation & IDisposable worked seemingly very well. But the ODBC driver was still not happy. I fooled around quite a bit with the Win32API Impersonation, changing the dwLogonType and more. But it would not work. The service could now see the file, and read from the file. But the ODBC driver gave me errors:
ERROR [S1000] [Lotus][ODBC Lotus Notes]Access to data denied.
ERROR [IM006] [Microsoft][ODBC Driver Manager] Driver's SQLSetConnectAttr failed
ERROR [01000] [Microsoft][ODBC Driver Manager] The driver doesn't support the version of ODBC behavior that the application requested (see SQLSetEnvAttr).
Then I thought of mapping the share with letter would be the simplest and easiest solution. Why not do this programmatically. I used a Win32 API called WNetUseConnection to connect to a UNC path with authentication. This will allow you to connect to a remote machine, even if it is not on the same domain, and a given username and password. I found this thread, with this code sample. It worked smoothly. The service could both see the file, and the ODBC driver didn’t object anymore. Problem solved!
Code sample is quoted here:
public class PinvokeWindowsNetworking
{
#region Consts
const int RESOURCE_CONNECTED = 0x00000001;
const int RESOURCE_GLOBALNET = 0x00000002;
const int RESOURCE_REMEMBERED = 0x00000003;
const int RESOURCETYPE_ANY = 0x00000000;
const int RESOURCETYPE_DISK = 0x00000001;
const int RESOURCETYPE_PRINT = 0x00000002;
const int RESOURCEDISPLAYTYPE_GENERIC = 0x00000000;
const int RESOURCEDISPLAYTYPE_DOMAIN = 0x00000001;
const int RESOURCEDISPLAYTYPE_SERVER = 0x00000002;
const int RESOURCEDISPLAYTYPE_SHARE = 0x00000003;
const int RESOURCEDISPLAYTYPE_FILE = 0x00000004;
const int RESOURCEDISPLAYTYPE_GROUP = 0x00000005;
const int RESOURCEUSAGE_CONNECTABLE = 0x00000001;
const int RESOURCEUSAGE_CONTAINER = 0x00000002;
const int CONNECT_INTERACTIVE = 0x00000008;
const int CONNECT_PROMPT = 0x00000010;
const int CONNECT_REDIRECT = 0x00000080;
const int CONNECT_UPDATE_PROFILE = 0x00000001;
const int CONNECT_COMMANDLINE = 0x00000800;
const int CONNECT_CMD_SAVECRED = 0x00001000;
const int CONNECT_LOCALDRIVE = 0x00000100;
#endregion
#region Errors
const int NO_ERROR = 0;
const int ERROR_ACCESS_DENIED = 5;
const int ERROR_ALREADY_ASSIGNED = 85;
const int ERROR_BAD_DEVICE = 1200;
const int ERROR_BAD_NET_NAME = 67;
const int ERROR_BAD_PROVIDER = 1204;
const int ERROR_CANCELLED = 1223;
const int ERROR_EXTENDED_ERROR = 1208;
const int ERROR_INVALID_ADDRESS = 487;
const int ERROR_INVALID_PARAMETER = 87;
const int ERROR_INVALID_PASSWORD = 1216;
const int ERROR_MORE_DATA = 234;
const int ERROR_NO_MORE_ITEMS = 259;
const int ERROR_NO_NET_OR_BAD_PATH = 1203;
const int ERROR_NO_NETWORK = 1222;
const int ERROR_BAD_PROFILE = 1206;
const int ERROR_CANNOT_OPEN_PROFILE = 1205;
const int ERROR_DEVICE_IN_USE = 2404;
const int ERROR_NOT_CONNECTED = 2250;
const int ERROR_OPEN_FILES = 2401;
private struct ErrorClass
{
public int num;
public string message;
public ErrorClass(int num, string message)
{
this.num = num;
this.message = message;
}
}
// Created with excel formula:
// ="new ErrorClass("&A1&", """&PROPER(SUBSTITUTE(MID(A1,7,LEN(A1)-6), "_", " "))&"""), "
private static ErrorClass[] ERROR_LIST = new ErrorClass[] {
new ErrorClass(ERROR_ACCESS_DENIED, "Error: Access Denied"),
new ErrorClass(ERROR_ALREADY_ASSIGNED, "Error: Already Assigned"),
new ErrorClass(ERROR_BAD_DEVICE, "Error: Bad Device"),
new ErrorClass(ERROR_BAD_NET_NAME, "Error: Bad Net Name"),
new ErrorClass(ERROR_BAD_PROVIDER, "Error: Bad Provider"),
new ErrorClass(ERROR_CANCELLED, "Error: Cancelled"),
new ErrorClass(ERROR_EXTENDED_ERROR, "Error: Extended Error"),
new ErrorClass(ERROR_INVALID_ADDRESS, "Error: Invalid Address"),
new ErrorClass(ERROR_INVALID_PARAMETER, "Error: Invalid Parameter"),
new ErrorClass(ERROR_INVALID_PASSWORD, "Error: Invalid Password"),
new ErrorClass(ERROR_MORE_DATA, "Error: More Data"),
new ErrorClass(ERROR_NO_MORE_ITEMS, "Error: No More Items"),
new ErrorClass(ERROR_NO_NET_OR_BAD_PATH, "Error: No Net Or Bad Path"),
new ErrorClass(ERROR_NO_NETWORK, "Error: No Network"),
new ErrorClass(ERROR_BAD_PROFILE, "Error: Bad Profile"),
new ErrorClass(ERROR_CANNOT_OPEN_PROFILE, "Error: Cannot Open Profile"),
new ErrorClass(ERROR_DEVICE_IN_USE, "Error: Device In Use"),
new ErrorClass(ERROR_EXTENDED_ERROR, "Error: Extended Error"),
new ErrorClass(ERROR_NOT_CONNECTED, "Error: Not Connected"),
new ErrorClass(ERROR_OPEN_FILES, "Error: Open Files"),
};
private static string GetErrorForNumber(int errNum)
{
foreach (ErrorClass er in ERROR_LIST)
{
if (er.num == errNum) return er.message;
}
return "Error: Unknown, " + errNum;
}
#endregion
[DllImport("Mpr.dll")]
private static extern int WNetUseConnection(
IntPtr hwndOwner,
NETRESOURCE lpNetResource,
string lpPassword,
string lpUserID,
int dwFlags,
string lpAccessName,
string lpBufferSize,
string lpResult
);
[DllImport("Mpr.dll")]
private static extern int WNetCancelConnection2(
string lpName,
int dwFlags,
bool fForce
);
[StructLayout(LayoutKind.Sequential)]
private class NETRESOURCE
{
public int dwScope = 0;
public int dwType = 0;
public int dwDisplayType = 0;
public int dwUsage = 0;
public string lpLocalName = "";
public string lpRemoteName = "";
public string lpComment = "";
public string lpProvider = "";
}
public static string ConnectToRemote(string remoteUNC, string username, string password)
{
return ConnectToRemote(remoteUNC, username, password, false);
}
public static string ConnectToRemote(string remoteUNC, string userName, string password, bool promptUser)
{
NETRESOURCE nr = new NETRESOURCE();
nr.dwType = RESOURCETYPE_DISK;
nr.lpRemoteName = remoteUNC;
int ret;
if (promptUser)
ret = WNetUseConnection(IntPtr.Zero, nr, "", "", CONNECT_INTERACTIVE | CONNECT_PROMPT, null, null, null);
else
ret = WNetUseConnection(IntPtr.Zero, nr, password, userName, 0, null, null, null);
if (ret == NO_ERROR) return null;
return GetErrorForNumber(ret);
}
public static string DisconnectRemote(string remoteUNC)
{
int ret = WNetCancelConnection2(remoteUNC, CONNECT_UPDATE_PROFILE, false);
if (ret == NO_ERROR) return null;
return GetErrorForNumber(ret);
}
}
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