Module urest.examples.simpleled

An example of a 'noun' class, able to serve as the basis for control of an LED attached to a GPIO pin

Overview

This is a reasonably minimal example of a 'noun' class, which inherits from APIBase. It also requires the Pin library from MicroPython: but should be able to be adapted to other GPIO libraries which provide a similar interface.

For an example of an application which uses this library, see: urest.examples.led_control

Tested Implementations

This version is written for MicroPython 3.4, and has been tested on:

  • Raspberry Pi Pico W

Licence

This class, and all included code, is made available under the terms of the MIT Licence

Copyright (c) 2022–2023 David Love

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Expand source code 
"""
An example of a 'noun' class, able to serve as the basis for control of an LED attached to a GPIO pin

Overview
--------

This is a reasonably minimal example of a 'noun' class, which inherits from
`urest.api.base.APIBase`. It also requires the `Pin` library from MicroPython:
but should be able to be adapted to other GPIO libraries which provide a similar
interface.

For an example of an application which uses this library, see: `urest.examples.led_control`

Tested Implementations
----------------------

This version is written for MicroPython 3.4, and has been tested on:

  * Raspberry Pi Pico W

Licence
-------

This class, and all included code, is made available under the terms of the MIT Licence

> Copyright (c) 2022--2023 David Love

> Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal in
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software is furnished to do so,
subject to the following conditions:

> The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

> THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
"""


# Import the Asynchronous IO Library, preferring the MicroPython library if
# available
try:
    from machine import Pin
except ImportError:
    print("Ignoring MicroPython include: machine")

from ..api.base import APIBase


class SimpleLED(APIBase):
    def __init__(self, pin):
        self._gpio = Pin(pin, Pin.OUT)
        self._gpio.off()

        self._state_attributes = dict(led=0)

    def set_state(self, state_attributes: dict):
        try:
            self._state_attributes["led"] = state_attributes["led"]

            if self._state_attributes["led"] == 0:
                self._gpio.off()
            else:
                self._gpio.on()

        except KeyError:
            # On exception try to return to a known good
            # state
            self._gpio.off()
            self._state_attributes["led"] = 0

    def get_state(self) -> dict:
        return dict(led=self._gpio.value())

    def delete_state(self):
        self._gpio.off()
        self._state_attributes["led"] = 0

    def update_state(self, state_attributes: dict):
        if self._state_attributes["led"] == 0:
            self._gpio.on()
            self._state_attributes["led"] = 1
        else:
            self._gpio.off()
            self._state_attributes["led"] = 0

Classes

class SimpleLED (pin)

The Abstract Base Class for the nouns, used in the response from the server.

This base class defines the minimum interface used in marshalling requests from the clients by the RESTServer class. The API defined by the server consists of 'nouns' representing the resources defined by the sub-classes of this base class, and the methods which act upon those resources (which map to the 'verbs' of the HTTP requests made to the RESTServer class.

Where data is returned to the client by the, e.g by the get_state method, JSON will ultimately be used as the encoding format. Sub-classes do not need to implement the saving of the object state to the client: however to assist they should be aware of the type of the each value returned as part of a key/value pair in the Dictionary.

When returning data to the client, the value of each entry in the Dictionary will attempt to be inferred using the normal Python type library. If the type can be identified, then an appropriate JSON type will be used: otherwise the value of that Dictionary entry will be returned as a string.

Warning: Data will be returned to the client 'as is'

No further checking on the validity (or otherwise) of the content of the Dictionary will be undertaken past this point. Anything that appear to be in a valid Dictionary will be returned to the client. It is the module consumers responsibility to ensure the returned data follows the form expected by those clients.

Expand source code 
class SimpleLED(APIBase):
    def __init__(self, pin):
        self._gpio = Pin(pin, Pin.OUT)
        self._gpio.off()

        self._state_attributes = dict(led=0)

    def set_state(self, state_attributes: dict):
        try:
            self._state_attributes["led"] = state_attributes["led"]

            if self._state_attributes["led"] == 0:
                self._gpio.off()
            else:
                self._gpio.on()

        except KeyError:
            # On exception try to return to a known good
            # state
            self._gpio.off()
            self._state_attributes["led"] = 0

    def get_state(self) -> dict:
        return dict(led=self._gpio.value())

    def delete_state(self):
        self._gpio.off()
        self._state_attributes["led"] = 0

    def update_state(self, state_attributes: dict):
        if self._state_attributes["led"] == 0:
            self._gpio.on()
            self._state_attributes["led"] = 1
        else:
            self._gpio.off()
            self._state_attributes["led"] = 0

Ancestors

Inherited members