Source code for canlib.kvrlib.remotedevice

import contextlib
import ctypes as ct
import time
from collections import namedtuple

from .address import Address
from .enums import BasicServiceSet, ConfigMode, NetworkState, RegulatoryDomain
from .exceptions import KvrBlank, KvrNoAnswer, KvrPasswordError, KvrUnreachable
from .structures import kvrAddress, kvrCipherInfoElement
from .wrapper import HOST_NAME_MIN_SIZE, dll

AddressInfo = namedtuple('AddressInfo', "address1 address2 netmask gateway is_dhcp")
ConnectionStatus = namedtuple(
    'ConnectionStatus', "state tx_rate rx_rate channel_number rssi tx_power"
ConnectionTestResult = namedtuple('ConnectionTestResult', "rssi rtt")
WlanScanResult = namedtuple(
    'WlanScanResult', "rssi channel_number mac bss_type ssid security_text"

[docs]def openDevice(channel_number, password="", validate_password=False): """Create a `RemoteDevice` object bound to a channel number Args: channel_number (`int`): CANlib channel number of the device to open password (`str`): Password of the device, if any validate_password (`bool`): Whether the password should be validated (defaults to `False`). This function checks that a remote-capable device is currently connection on the channel `channel_number`. If `validate_password` is ``True``, it also checks that the password supplied is correct. If any of these checks fail, a `ValueError` will be raised. """ # quickly check that a remote device is connected to this channel number try: num = ct.c_int32() dll.kvrConfigNoProfilesGet(channel_number, ct.byref(num)) except KvrUnreachable: raise ValueError("No remote device on channel " + str(channel_number)) rdev = RemoteDevice(channel_number, password) if validate_password: if not rdev.password_valid(): raise ValueError("Wrong password supplied") return rdev
[docs]class RemoteDevice: """A remote-capable Kvaser device This class is normally instantiated with `openDevice`:: rdev = kvrlib.openDevice(CHANNEL_NUMBER) Once this is done, the currently active profile can be accessed:: active = rdev.active_profile All profiles, including the active one, are `ConfigProfile` objects, see that documentation for all the operations available for profile objects. The full list of profiles a device has can be inspected using ``rdev.profiles``. This is a `RemoteDevice.ProfileList` object, which works much like a list:: # The profile list can be indexed first = rdev.profiles[0] # We can check if a configuration belongs to this device with 'in' assert first in rdev.profiles # The length of the profile list is the number of profiles num_profiles = len(rdev.profiles) # Using the number of profiles, we can get the last one last = rdev.profiles[num_profiles - 1] # But negative indexes also work and are a better way of getting # the last profile last = rdev.profiles[-1] # You can also iterate over all profiles for profile in rdev.profiles: ... `RemoteDevice` also lets you access a variety of information about the specific device, as well as the ability to do a WLAN scan with `RemoteDevice.wlan_scan`. If the device is password protected, that password can be passed to `openDevice`:: protected_device = kvrlib.openDevice(0, password="Once upon a playground rainy") After the object is created, the password is available as:: password = protected_device.password The password can be changed with:: protected_device.password = "Wolves without teeth" The reason the password is stored as clear-text is because it must be supplied to the underlying library each time an operation is done using this and related classes. This also means that the password is only validated, and required, when one of the functions requiring a password is called. If the device is not password-protected, the password should be an empty string:: unprotected_device = kvrlib.openDevice(1) assert unprotected_device.password == '' """
[docs] class ProfileList: """The available profiles in a remote-capable device This is the type of `RemoteDevice.profiles`. It implements the following: * ``len(profiles)`` * ``profile in profiles`` * ``profile[index]`` """ def __init__(self, channel_number): self.channel_number = channel_number def __len__(self): num = ct.c_int32() dll.kvrConfigNoProfilesGet(self.channel_number, ct.byref(num)) return num.value def __contains__(self, profile): if not isinstance(profile, ConfigProfile): return False elif profile.channel_number != self.channel_number: # Multichannel devices must use same CANlib channel return False else: return 0 <= profile.profile_number < len(self) def __getitem__(self, index): if index < 0: index = len(self) + index profile = ConfigProfile(self, index) if profile not in self: raise KeyError(index) else: return profile
def __init__(self, channel_number, password): self.channel_number = channel_number self.password = password self.profiles = self.ProfileList(self.channel_number) @property def active_profile(self): """`ConfigProfile`: The currently active profile Activating another profile is done by assigning this attribute to another profile:: new_profile = remote_device.profiles[index] remote_device.active_profile = new_profile The value assigned to this property must be a `ConfigProfile` that belongs to this device, i.e. the following must be ``True``:: new_profile in remote_device.profiles """ profile_number = ct.c_int32() dll.kvrConfigActiveProfileGet(self.channel_number, profile_number) return ConfigProfile(self, profile_number.value) @active_profile.setter def active_profile(self, val): # pause required if not isinstance(val, ConfigProfile): raise TypeError("active_profile must be a kvrlib.ConfigProfile object") elif val not in self.profiles: raise ValueError("active_profile must be a profile of this device") dll.kvrConfigActiveProfileSet(self.channel_number, val.profile_number) @property def address_info(self): """`AddressInfo`: Information about network address settings Note: Accessing this attribute requires the correct password be set on the object. """ address1 = kvrAddress() address2 = kvrAddress() netmask = kvrAddress() gateway = kvrAddress() dhcp = ct.c_int32() with self._config_handle(self.password) as handle: dll.kvrNetworkGetAddressInfo( handle, ct.byref(address1), ct.byref(address2), ct.byref(netmask), ct.byref(gateway), ct.byref(dhcp), ) address1 = Address.from_c(address1) address2 = Address.from_c(address2) netmask = Address.from_c(netmask) gateway = Address.from_c(gateway) dhcp = bool(dhcp) return AddressInfo(address1, address2, netmask, gateway, dhcp) @property def connection_status(self): """`ConnectionStatus`: Connection status information The returned tuple is a ``(state, tx_rate, rx_rate, channel, rssi, tx_power)`` namedtuple of: #. ``state`` (`NetworkState`): Network connection state #. ``tx_rate`` (`int`): Transmit rate in kbit/s #. ``rx_rate`` (`int`): Receive rate in kbit/s #. ``channel`` (`int`): Channel #. ``rssi`` (`int`): Receive Signal Strength Indicator #. ``tx_power`` (`int`): Transmit power level in dB Note: Accessing this attribute requires the correct password be set on the object. """ state = ct.c_int32() tx_rate = ct.c_int32() rx_rate = ct.c_int32() channel = ct.c_int32() rssi = ct.c_int32() tx_power = ct.c_int32() with self._config_handle(self.password) as handle: dll.kvrNetworkGetConnectionStatus( handle, ct.byref(state), ct.byref(tx_rate), ct.byref(rx_rate), ct.byref(channel), ct.byref(rssi), ct.byref(tx_power), ) state = NetworkState(state.value) tx_rate = tx_rate.value rx_rate = rx_rate.value channel = channel.value rssi = rssi.value tx_power = tx_power.value return ConnectionStatus(state, tx_rate, rx_rate, channel, rssi, tx_power) @property def hostname(self): """`str`: Device's hostname Note: Accessing this attribute requires the correct password be set on the object. """ buf = ct.create_string_buffer(HOST_NAME_MIN_SIZE) with self._config_handle(self.password) as handle: dll.kvrNetworkGetHostName( handle, buf, ct.sizeof(buf), ) return buf.value.decode('utf-8')
[docs] def connection_test(self): """Creates a connection test for this device Returns: `ConnectionTest` See the documentation of `ConnectionTest` for more information. Note: Accessing this attribute requires the correct password be set on the object. """ handle = self._loose_config_handle(self.password) return ConnectionTest(handle)
[docs] def password_valid(self): """Checks whether the password set is valid Returns: `bool`: ``True`` if the password is valid, ``False`` otherwise. """ try: handle = self._loose_config_handle(self.password) except KvrPasswordError: return False else: dll.kvrConfigClose(handle) return True
[docs] def wlan_scan(self, active=False, bss_type=BasicServiceSet.ANY, domain=RegulatoryDomain.WORLD): """Creates and starts a wlan scan for this device Returns: `WlanScan` See the documentation of `WlanScan` for more information. Note: Accessing this attribute requires the correct password be set on the object. """ handle = self._loose_config_handle(self.password) scan = WlanScan(handle) scan._start(active, bss_type, domain) return scan
def _loose_config_handle(self, password): password = ct.create_string_buffer(password.encode('utf-8')) handle = ct.c_int32() dll.kvrConfigOpen(self.channel_number, ConfigMode.R, password, handle) return handle @contextlib.contextmanager def _config_handle(self, password): handle = self._loose_config_handle(password) yield handle dll.kvrConfigClose(handle)
[docs]class ConfigProfile: """A configuration profile of a remote-capable device The active profile for a `RemoteDevice`, ``rdev``, is accessed with:: profile = rdev.active_profile Other profiles are accessed with ``profiles``:: first = rdev.profiles[0] See the documentation for `RemoteDevice` for more information on how to get `ConfigProfile` objects. The specific configuration of a profile can be read:: xml_string = And it can also be written back:: profile.write(xml_string) The password used by this object is taken from its parent `RemoteDevice` object. See that documentation for how to set the password. """ XML_BUFFER_SIZE = 2046 def __init__(self, device, profile_number): self._device = device self.profile_number = profile_number def __repr__(self): return "<ConfigProfile number {pn} of device on CANlib channel {cn}>".format( pn=self.profile_number, cn=self.channel_number ) @property def channel_number(self): """`int`: The CANlib channel number used to communicate with the device""" return self._device.channel_number @property def info(self): """`str`: A simplified version of the configuration It is not necessary to know the configuration password to access this information. Note that the partial XML data returned is not enough to reconfigure a device. """ xml_buffer = ct.create_string_buffer(self.XML_BUFFER_SIZE) try: dll.kvrConfigInfoGet( self.channel_number, self.profile_number, xml_buffer, ct.sizeof(xml_buffer) ) except KvrBlank: xml = None else: xml = xml_buffer.value.decode('utf-8') return xml @property def password(self): """`str`: The password used to communicate with the device""" return self._device.password
[docs] def clear(self): """Clear the configuration This will also clear any previously set device password. Note: This method requires the parent `RemoteDevice` to have the correct password. """ # pause required with self._open(self.password, ConfigMode.ERASE) as handle: dll.kvrConfigClear(handle)
[docs] def read(self): """Read the configuration Returns either an XML string, or `None` if there is no configuration. Note that `ConfigProfile.write` can handle `None`; in other words:: xml = # Do anything, including writing new configurations ... profile.write(xml) Will always work even if ``xml`` is `None`. This would mean that the profile originally had an empty configuration, and it will once again have an empty configuration at the end. Note: This method requires the parent `RemoteDevice` to have the correct password. """ xml_buf = ct.create_string_buffer(self.XML_BUFFER_SIZE) with self._open(self.password, ConfigMode.R) as handle: try: dll.kvrConfigGet(handle, xml_buf, ct.sizeof(xml_buf)) except KvrBlank: pass try: xml_text = xml_buf.value.decode('utf-8') except UnicodeDecodeError: xml_text = xml_buf.value.decode('cp1252') return xml_text or None
[docs] def write(self, xml): """Write the configuration area This function takes as its single argument either an xml string that will be written to this profile, or `None` in which case the configuration will be cleared. Note: This method requires the parent `RemoteDevice` to have the correct password. """ if xml is None: self.clear() else: xml_buf = ct.create_string_buffer(xml.encode('utf-8')) with self._open(self.password, ConfigMode.RW) as handle: dll.kvrConfigSet(handle, xml_buf)
@contextlib.contextmanager def _open(self, password, mode): password = ct.create_string_buffer(password.encode('utf-8')) handle = ct.c_int32() dll.kvrConfigOpenEx( self.channel_number, mode, password, ct.byref(handle), self.profile_number, ) yield handle dll.kvrConfigClose(handle)
[docs]class ConnectionTest: """A connection test for a specific device A connection test for a `RemoteDevice`, ``rdev``, is created by:: test = rdev.connection_test() While a connection test is running, the device will connect and start pinging itself to measure round-trip time (RTT) and Receive Signal Strength Indicator (RSSI). A `ConnectionTest` is started with `ConnectionTest.start` and stopped with `ConnectionTest.stop`, after which its results are retrieved by `ConnectionTest.results`. If it is acceptable to block while the test is running, these three calls can be combined into ``:: results = print(results) Connection tests are automatically closed when garbage-collected, but they can also be closed manually with `ConnectionTest.close`. """ def __init__(self, config_handle): self._handle = config_handle def __del__(self): self.close() def __enter__(self): return self def __exit__(self, type, value, traceback): self.close()
[docs] def close(self): """Close the internal handle""" if self._handle is not None: dll.kvrConfigClose(self._handle) self._handle = None
[docs] def results(self, maxresults=20): """Get the results from a connection test The test must have been running for any results to be available. This function returns a `ConnectionTestResult`, which is a namedtuple of ``(rssi, rtt)``. Both ``rssi`` and ``rtt`` are tuples containing a number of individual results for RSSI and RTT. Args: maxresults (`int`): The maximum number of rssi and rtt numbers to return. The returned ``rssi`` and ``rtt`` will be tuples with this long or the number of results available long, whichever is shortest. """ rssi_size = maxresults rssi = (ct.c_int32 * rssi_size)() rssi_count = ct.c_uint32() rtt_size = maxresults rtt = (ct.c_uint32 * rtt_size)() rtt_count = ct.c_uint32() dll.kvrNetworkGetRssiRtt( self._handle, rssi, len(rssi), ct.byref(rssi_count), rtt, len(rtt), ct.byref(rtt_count), ) rssi = rssi[: rssi_count.value] rtt = rtt[: rtt_count.value] return ConnectionTestResult(tuple(rssi), tuple(rtt))
[docs] def run(self, duration, maxresults=20): """Run a connection test and return its results. This function calls `ConnectionTest.start`, then blocks for `duration` seconds, then calls `ConnectionTest.stop` before finally returning the `ConnectionTestResult` from `ConnectionTest.results`. Args: duration (`int`): Seconds to run the test for. maxresults (`int`): Passed to `ConnectionTest.results` as ``maxlen``. """ self.start() time.sleep(duration) self.stop() return self.results(maxresults)
[docs] def start(self): """Start the connection test""" dll.kvrNetworkConnectionTest(self._handle, 1)
[docs] def stop(self): """Stop the connection test""" dll.kvrNetworkConnectionTest(self._handle, 0)
[docs]class WlanScan: """A wlan scan for this device The device starts scanning as soon as this object is created by `RemoteDevice.wlan_scan`:: scan = rdev.wlan_scan() When calling `RemoteDevice.wlan_scan`, you can also specify whether the scan should be an active one, the Basic Service Set (bss) to use, and the regulatory domain:: scan = rdev.wlan_scan( active=True, bss=kvrlib.BasicServiceSet.INFRASTRUCTURE, domain=kvrlib.RegulatoryDomain.EUROPE_ETSI, ) Results from the scan are retrieved by iterating over the `WlanScan` object: for result in scan: print(result) When getting the next result, the code will block until a new result is available or until no more results are available, in which case the iteration stops. Wlan scans are automatically closed when garbage-collected, but they can also be closed manually with `WlanScan.close`. """ def __init__(self, config_handle): self._handle = config_handle def __enter__(self): return self def __exit__(self, type, value, traceback): self.close() def __del__(self): self.close() def __iter__(self): try: while True: try: yield self._get_result() except KvrNoAnswer: # "waiting for further scan results" time.sleep(0.1) except KvrBlank: # "no further scan results are available" return
[docs] def close(self): """Closes the internal handle""" if self._handle is not None: dll.kvrConfigClose(self._handle) self._handle = None
def _get_result(self): rssi = ct.c_int32() channel = ct.c_int32() mac = kvrAddress() bss_type = ct.c_int32() ssid = ct.create_string_buffer(32) capability = ct.c_uint32() type_wpa = ct.c_uint32() wpa_info = kvrCipherInfoElement() rsn_info = kvrCipherInfoElement() dll.kvrWlanGetScanResults( self._handle, ct.byref(rssi), ct.byref(channel), ct.byref(mac), ct.byref(bss_type), ssid, ct.byref(capability), ct.byref(type_wpa), ct.byref(wpa_info), ct.byref(rsn_info), ) security_text = ct.create_string_buffer(180) dll.kvrWlanGetSecurityText( security_text, ct.sizeof(security_text), capability, type_wpa, wpa_info, rsn_info, ) return WlanScanResult( rssi.value, channel.value, Address.from_c(mac), BasicServiceSet(bss_type.value), ssid.value, security_text.value, ) def _start(self, active, bss_type, domain): dll.kvrWlanStartScan( self._handle, active, bss_type, domain, )