Controlling physical devices from a Raspberry Pi and approvals in Force.com!

button.py

import RPi.GPIO as GPIO
import time
import urllib
import urllib2
import os
import json

GPIO.setmode(GPIO.BCM)
GPIO.setup(24, GPIO.OUT)

count = 0
last = 0
url = 'http://home.superpat.com:5000/pins/25'

class ForceClient:
    def __init__(self, options):
        self.client_id = options.get('client_id', None)
        if self.client_id is None:
            print('You MUST set the client_id')
            sys.exit(1)
        self.client_secret = options.get('client_secret', None)
        if self.client_secret is None:
            print('You MUST set the client_secret')
            sys.exit(1)
        self.username = options.get('username', None)
        if self.username is None:
            print('You MUST set the username')
            sys.exit(1)
        self.password = options.get('password', None)
        if self.password is None:
            print('You MUST set the password')
            sys.exit(1)
        self.login_server = options.get('login_server', 'https://login.salesforce.com')

        self.oauth = self.get_token()

    def get_token(self):
        # Do OAuth username/password
        token_url = '%s/services/oauth2/token' % self.login_server

        params = urllib.urlencode({
          'grant_type': 'password',
          'client_id': self.client_id,
          'client_secret': self.client_secret,
          'username': self.username,
          'password': self.password
        })

        print('Getting token from %s' % token_url)

        try:
            data = urllib2.urlopen(token_url, params).read()
        except urllib2.URLError, e:
            if hasattr(e, 'code'):
                if e.code == 400:
                    print('Check the client_id, client_secret, username and password')
                else:
                    print('HTTP status %d' % e.code)
            elif hasattr(e, 'reason'):
                print('Error posting to URL %s: %d %s' % 
                                (token_url, e.reason[0], e.reason[1]),
                                'Check the login_server')
            else:
                print('Unknown error %s' % e)
        # print('Got token %s' % data)
        print('Got token')
        oauth = json.loads(data)
        print('Logged in to %s as %s' % (self.login_server, self.username))

        return oauth   

    def postToApexRest(self, method, data):
        query_url = '%s/services/apexrest/%s' % (self.oauth['instance_url'], method)
        headers = {
            'Authorization': 'Bearer %s' % self.oauth['access_token'],
            'Content-type': 'application/json'
        }
        req = urllib2.Request(query_url, data, headers)
        f = urllib2.urlopen(req)
        response = f.read()
        f.close()
        # print response

   
client = ForceClient({
   'client_id': os.environ['CLIENT_ID'],
   'client_secret': os.environ['CLIENT_SECRET'],
   'username': os.environ['USERNAME'],
   'password': os.environ['PASSWORD'],
})

while True:
   inputValue = GPIO.input(24)
   if (inputValue != last):
      data = 'true' if (inputValue == 1) else 'false'
      print("Button %s" % ("pressed" if (inputValue == 1) else "released"))
      client.postToApexRest('button', data)
      last = inputValue
   time.sleep(.01)

ButtonController.cls

@RestResource(urlMapping='/button/*')
global class ButtonController {
    @future(callout=true)
    public static void light(Boolean state) {
        HTTPRequest outreq = new HTTPRequest();
        outreq.setEndpoint('http://api.superpat.com:5000/pins/25');
        outreq.setMethod('POST');
        outreq.setHeader('Content-Type', 'application/json');
        outreq.setBody(state ? 'true' : 'false');

        Http h = new Http();
        HttpResponse outres = h.send(outreq);
        if (outres.getStatusCode() != 204) {
            System.debug(outres.getBody());
        }        
    }

    @HttpPost   
    global static void pressButton() {
        RestRequest req = RestContext.request;
        RestResponse res = RestContext.response;
        
        Boolean state = Boolean.valueOf(req.requestBody.toString());
        System.debug('Button pressed - state = ' + state);
        
        if (state) {
            // Just one light for now
            Light__c light = [SELECT Id, State__c FROM Light__c LIMIT 1];
            if (light.State__c == 'Off') {
                light.State__c = 'Request On';
                update light;
                
                // Create an approval request
                Approval.ProcessSubmitRequest req1 = 
                    new Approval.ProcessSubmitRequest();
                req1.setComments('Please turn the light on, Dad!');
                req1.setObjectId(light.Id);
                
                // Submit the approval request for the account
                Approval.ProcessResult result = Approval.process(req1);
                
                System.debug('Submitted for approval successfully: '+result.isSuccess());
            } else if (light.State__c == 'On'){
                light.State__c = 'Off';
                update light;
            }
        }
        
        res.statusCode = 204;
    }
}

LightTrigger.cls

trigger LightTrigger on Light__c (before update) {
    for (Light__c light : Trigger.new) {
        Light__c beforeUpdate = System.Trigger.oldMap.get(light.Id);
        if (light.State__c == 'On' && beforeUpdate.State__c != 'On') {
            ButtonController.light(true);
        } else if (light.State__c == 'Off' && beforeUpdate.State__c != 'Off') {
            ButtonController.light(false);
        }
    }
}

pins.py

import RPi.GPIO as GPIO
import time

GPIO.setmode(GPIO.BCM)
# We only work with pin 25 for now, but it would be easy to extend this to as many pins as desired
GPIO.setup(25, GPIO.OUT)
GPIO.output(25, GPIO.HIGH)
time.sleep(1)
GPIO.output(25, GPIO.LOW)

from flask import Flask, request

app = Flask(__name__)  

@app.route('/pins/<int:pin>', methods=['POST'])  
def pins(pin):  
  state = GPIO.HIGH if request.json else GPIO.LOW
  print("Setting pin %d to %s" % (pin, state))
  GPIO.output(pin, state)
  return '', 204
if __name__ == "__main__":  
  app.run('0.0.0.0')