Figuring which printer name corresponds to which device ID

Question

My goal is to open a printer connected via USB using the CreateFile (and then issue some WriteFiles and ReadFiles).

If the pri

Answer 1

Try this (Python code):

import _winreg

HKLM = _winreg.HKEY_LOCAL_MACHINE

#------------------------------------------------------------------------------
def getDevicePath(printerName):
    key = _winreg.OpenKey(HKLM,
        r"SOFTWARE\Microsoft\Windows NT\CurrentVersion\Print\Printers\%s" \
        % printerName)

    value =_winreg.QueryValueEx(key, "Port")[0]
    assert value.startswith("USB"), \
           "Port does not start with 'USB': %s" % value

    printerPortNumber = int(value.replace(u"USB", u""))

    key = _winreg.OpenKey(HKLM,
            r"SYSTEM\CurrentControlSet\Control\DeviceClasses" \
            r"\{28d78fad-5a12-11d1-ae5b-0000f803a8c2}")

    idx = 0
    devicePath = None
    while True:
        try:
            subKeyName = _winreg.EnumKey(key, idx)
            subKey = _winreg.OpenKey(key, subKeyName)

            try:
                subSubKey = _winreg.OpenKey(subKey, r"#\Device Parameters")
                baseName = _winreg.QueryValueEx(subSubKey, "Base Name")[0]
                portNumber = _winreg.QueryValueEx(subSubKey, "Port Number")[0]
                if baseName == "USB" and portNumber == printerPortNumber:
                    devicePath = subKeyName.replace("##?#USB", r"\\?\usb")
                    break

            except WindowsError:
                continue

            finally:
                idx += 1

        except WindowsError:
            break

    return devicePath