Connecting to a protected WiFi from Python on Linux

This shows how to do this for WPA.

First of all, ditch connman and use NetworkManager. The example script below shows how to enable wireless support, check if network with given SSID is available, connect to that SSID using a WPA passphrase, and then disconnect from the network and disable wireless. I'm fairly sure that this script can be improved, but the current version serves enough as an example:

#!/usr/bin/python# This script shows how to connect to a WPA protected WiFi network# by communicating through D-Bus to NetworkManager 0.9.## Reference URLs:# http://projects.gnome.org/NetworkManager/developers/# http://projects.gnome.org/NetworkManager/developers/settings-spec-08.htmlimport dbusimport timeSEEKED_SSID = "skynet"SEEKED_PASSPHRASE = "qwertyuiop"if __name__ == "__main__":    bus = dbus.SystemBus()    # Obtain handles to manager objects.    manager_bus_object = bus.get_object("org.freedesktop.NetworkManager",                                        "/org/freedesktop/NetworkManager")    manager = dbus.Interface(manager_bus_object,                             "org.freedesktop.NetworkManager")    manager_props = dbus.Interface(manager_bus_object,                                   "org.freedesktop.DBus.Properties")    # Enable Wireless. If Wireless is already enabled, this does nothing.    was_wifi_enabled = manager_props.Get("org.freedesktop.NetworkManager",                                         "WirelessEnabled")    if not was_wifi_enabled:        print "Enabling WiFi and sleeping for 10 seconds ..."        manager_props.Set("org.freedesktop.NetworkManager", "WirelessEnabled",                          True)        # Give the WiFi adapter some time to scan for APs. This is absolutely        # the wrong way to do it, and the program should listen for        # AccessPointAdded() signals, but it will do.        time.sleep(10)    # Get path to the 'wlan0' device. If you're uncertain whether your WiFi    # device is wlan0 or something else, you may utilize manager.GetDevices()    # method to obtain a list of all devices, and then iterate over these    # devices to check if DeviceType property equals NM_DEVICE_TYPE_WIFI (2).    device_path = manager.GetDeviceByIpIface("wlan0")    print "wlan0 path: ", device_path    # Connect to the device's Wireless interface and obtain list of access    # points.    device = dbus.Interface(bus.get_object("org.freedesktop.NetworkManager",                                           device_path),                            "org.freedesktop.NetworkManager.Device.Wireless")    accesspoints_paths_list = device.GetAccessPoints()    # Identify our access point. We do this by comparing our desired SSID    # to the SSID reported by the AP.    our_ap_path = None    for ap_path in accesspoints_paths_list:        ap_props = dbus.Interface(            bus.get_object("org.freedesktop.NetworkManager", ap_path),            "org.freedesktop.DBus.Properties")        ap_ssid = ap_props.Get("org.freedesktop.NetworkManager.AccessPoint",                               "Ssid")        # Returned SSID is a list of ASCII values. Let's convert it to a proper        # string.        str_ap_ssid = "".join(chr(i) for i in ap_ssid)        print ap_path, ": SSID =", str_ap_ssid        if str_ap_ssid == SEEKED_SSID:            our_ap_path = ap_path            break    if not our_ap_path:        print "AP not found :("        exit(2)    print "Our AP: ", our_ap_path    # At this point we have all the data we need. Let's prepare our connection    # parameters so that we can tell the NetworkManager what is the passphrase.    connection_params = {        "802-11-wireless": {            "security": "802-11-wireless-security",        },        "802-11-wireless-security": {            "key-mgmt": "wpa-psk",            "psk": SEEKED_PASSPHRASE        },    }    # Establish the connection.    settings_path, connection_path = manager.AddAndActivateConnection(        connection_params, device_path, our_ap_path)    print "settings_path =", settings_path    print "connection_path =", connection_path    # Wait until connection is established. This may take a few seconds.    NM_ACTIVE_CONNECTION_STATE_ACTIVATED = 2    print """Waiting for connection to reach """ \          """NM_ACTIVE_CONNECTION_STATE_ACTIVATED state ..."""    connection_props = dbus.Interface(        bus.get_object("org.freedesktop.NetworkManager", connection_path),        "org.freedesktop.DBus.Properties")    state = 0    while True:        # Loop forever until desired state is detected.        #        # A timeout should be implemented here, otherwise the program will        # get stuck if connection fails.        #        # IF PASSWORD IS BAD, NETWORK MANAGER WILL DISPLAY A QUERY DIALOG!        # This is something that should be avoided, but I don't know how, yet.        #        # Also, if connection is disconnected at this point, the Get()        # method will raise an org.freedesktop.DBus.Error.UnknownMethod        # exception. This should also be anticipated.        state = connection_props.Get(            "org.freedesktop.NetworkManager.Connection.Active", "State")        if state == NM_ACTIVE_CONNECTION_STATE_ACTIVATED:            break        time.sleep(0.001)    print "Connection established!"    #    # Connection is established. Do whatever is necessary.    # ...    #    print "Sleeping for 5 seconds ..."    time.sleep(5)    print "Disconnecting ..."    # Clean up: disconnect and delete connection settings. If program crashes    # before this point is reached then connection settings will be stored    # forever.    # Some pre-init cleanup feature should be devised to deal with this problem,    # but this is an issue for another topic.    manager.DeactivateConnection(connection_path)    settings = dbus.Interface(        bus.get_object("org.freedesktop.NetworkManager", settings_path),        "org.freedesktop.NetworkManager.Settings.Connection")    settings.Delete()    # Disable Wireless (optional step)    if not was_wifi_enabled:        manager_props.Set("org.freedesktop.NetworkManager", "WirelessEnabled",                          False)    print "DONE!"    exit(0)