Programming Your Home Mike Riley

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6.10 Writing the Script

The package delivery monitoring script needs to perform several functions, from listening for and reacting to triggers from the package delivery monitoring hardware to sending an email alert about the event and everything in between. Specifically, the script needs to do the following:

Listen for threshold exceeded events (i.e., package delivery and removal) sent via the soft serial port communications between the XBee radios.
Timestamp these events generated by the force sensitive resistor in the deliverystatus table.
If a high value is received (i.e., a package is delivered), query tracking numbers stored in the tracking table. If a low value is received (i.e., a package is removed), send an email alert stating such and return execution of the script back to listening for delivery events.
If a high value is received, wait for a specified time before querying the tracking table to allow time for the courier to update the delivery records.
Iterate over undelivered tracking numbers and poll the appropriate courier’s web service records for delivery confirmation status.
If the courier’s web service results report a delivery confirmation, change the status of the tracking number record in the local tracking database table to 1 (i.e., boolean value for delivered).
Send an email via Gmail’s secure SMTP gateway that contains the results of delivery activity in the body of the message. Note that you will need login access to an active Gmail account for this function to work.
Return to listening for additional package delivery events.

With those steps in mind, here’s the complete script.

PackageDeliveryDetector/packagedeliverydetector.py
①	`from datetime import datetime`
	`import packagetrack`
	`from packagetrack import Package`
	`import serial`
	`import smtplib`
	`import sqlite3`
	`import time`
	`import os`
	`import sys`
	`# Connect to the serial port`
	`XBeePort = serial.Serial('/dev/tty.YOUR_SERIAL_DEVICE', \`
②	`baudrate = 9600, timeout = 1)`

③	`def send_email(subject, message):`
	`recipient = 'YOUR_EMAIL_RECIPIENT@DOMAIN.COM'`
	`gmail_sender = 'YOUR_GMAIL_ACCOUNT_NAME@gmail.com'`
	`gmail_password = 'YOUR_GMAIL_ACCOUNT_PASSWORD'`

	`# Establish secure TLS connection to Gmail SMTP gateway`
	`gmail_smtp = smtplib.SMTP('smtp.gmail.com',587)`
	`gmail_smtp.ehlo()`
	`gmail_smtp.starttls()`
	`gmail_smtp.ehlo`

	`# Log into Gmail`
	`gmail_smtp.login(gmail_sender, gmail_password)`

	`# Format message`
	`mail_header = 'To:' + recipient + '\n' + 'From: ' + gmail_sender + '\n' \`
	`+ 'Subject: ' + subject + '\n'`
	`message_body = message`
	`mail_message = mail_header + '\n ' + message_body + ' \n\n'`

	`# Send formatted message`
	`gmail_smtp.sendmail(gmail_sender, recipient, mail_message)`
	`print("Message sent")`

	`# Close connection`
	`gmail_smtp.close()`

④	`def process_message(msg):`
	`try:`
	`# Remember to use the full correct path to the`
	`# packagedelivery.sqlite file`
	`connection = sqlite3.connect("packagedelivery.sqlite")`
	`cursor = connection.cursor()`

	`# Get current date and time and format it accordingly`
	`timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")`

	`sqlstatement = "INSERT INTO delivery (id, time, event) \`
	`VALUES(NULL, \"%s\", \"%s\")" % (timestamp, msg)`
	`cursor.execute(sqlstatement)`
	`connection.commit()`
	`cursor.close()`
	`except:`
	`print("Problem accessing delivery table in the " \`
	`+ "packagedelivery database")`

	`if (msg == "Delivery"):`

	`# Wait 5 minutes (300 seconds) before polling the various couriers`
	`time.sleep(300)`

	`try:`
	`connection = sqlite3.connect("packagedelivery.sqlite")`
	`cursor = connection.cursor()`
	`cursor.execute('SELECT * FROM tracking WHERE '\`
	`+ 'delivery_status=0')`
	`results = cursor.fetchall()`
	`message = ""`

	`for x in results:`
	`tracking_number = str(x[1])`
	`description = str(x[2])`
	`print tracking_number`

	`package = Package(tracking_number)`
	`info = package.track()`
	`delivery_status = info.status`
	`delivery_date = str(info.delivery_date)`

	`if (delivery_status.lower() == 'delivered'):`
	`sql_statement = 'UPDATE tracking SET \`
	`delivery_status = "1", delivery_date = \`
	`"' + delivery_date + \`
	`'" WHERE tracking_number = "' \`
	`+ tracking_number + '";'`
	`cursor.execute(sql_statement)`
	`connection.commit()`
	`message = message + description \`
	`+ ' item with tracking number ' \`
	`+ tracking_number \`
	`+ ' was delivered on ' \`
	`+ delivery_date +'\n\n'`

	`# Close the cursor`
	`cursor.close()`

	`# If delivery confirmation has been made, send an email`
	`if (len(message) > 0):`
	`print message`
	`send_email('Package Delivery Confirmation', message)`
	`else:`
	`send_email('Package Delivery Detected', 'A ' \`
	`+ 'package delivery event was detected, ' \`
	`+ 'but no packages with un-confirmed ' \`
	`+ 'delivery tracking numbers in the database ' \`
	`+ 'were able to be confirmed delivered by ' \`
	`+ 'the courier at this time.')`
	`except:`
	`print("Problem accessing tracking table in the " \`
	`+ "packagedelivery database")`

	`else:`
	`send_email('Package(s) Removed', 'Package removal detected.')`

⑤	`if sys.platform == "win32":`
	`os.system("cls")`
	`else:`
	`os.system("clear")`

	`print("Package Delivery Detector running...\n")`
	`try:`
	`while 1:`
	`# listen for inbound characters from the XBee radio`
	`XBee_message = XBeePort.readline()`

	`# Depending on the type of delivery message received,`
	`# log and lookup accordingly`
	`if "Delivery" in XBee_message:`
	`# Get current date and time and format it accordingly`
	`timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")`
	`print("Delivery event detected - " + timestamp)`
	`process_message("Delivery")`

	`if "Empty" in XBee_message:`
	`# Get current date and time and format it accordingly`
	`timestamp = datetime.now().strftime("%Y-%m-%d %H:%M:%S")`
	`print("Parcel removal event detected - " + timestamp)`
	`process_message("Empty")`

⑥	`except KeyboardInterrupt:`
	`print("\nQuitting the Package Delivery Detector.\n")`
	`pass`

①: Begin by importing the script’s dependencies on the custom packagetrack library along with the serial, smtplib, sqlite3, time, os, and sys standard Python libraries.
②: Identify the serial port of the XBee radio attached to the computer’s serial port. This radio will listen for incoming transmissions from the paired XBee radio attached to the Arduino connected to the force sensitive resistor. Replace the ’/dev/tty.YOUR_SERIAL_DEVICE’ placeholder with the actual path of the your XBee radio’s attached serial port value.
③: This is the send_mail routine that is used in the process_message routine, and thus it needs to be declared first. Replace the recipient, gmail_sender, and gmail_password placeholder values with your desired recipient and Gmail account credentials.
④: The process_message routine is where most of the action happens in the script. Connect to the packagedelivery.sqlite SQLite database and log the type of event received. If a delivery message is received, the script waits for five minutes before polling the FedEx and UPS web services to give the shipper enough time to log the delivery status to the central servers. Then, the tracking table in the packagedelivery.sqlite database is queried for any undelivered tracking numbers. These numbers are submitted one at a time to the respective web service. If a delivery confirmation is returned, its positive response is logged to the database with the confirmed delivery date, as well as appended to the body of the email message to be sent via the send_email routine.
⑤: This is the main loop of the script. Begin by clearing the screen and listening for a “Delivery” or “Empty” message from the Arduino-attached XBee radio and invoke the process_message routine.
⑥: Gracefully exit the script if a Ctrl-C keypress is detected.

Save the script as packagedelivery.py and execute it with the python packagedelivery.py command. If any errors arise, check syntax and code-line indentations, since Python is very strict about line formatting. If the script starts up without any complaints, you’re ready to test it out.

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