Send apns notification to iOS device in Python

apns.py

import socket
import ssl
import json
import struct
import binascii

# device token returned when the iPhone application
# registers to receive alerts

device_token = b'XXXX ... XXX' 

payload = {
    'aps': {
        'alert':'Test',
        'sound':'default',
    },
    'msgData': { 'foo': 'bar' },
}

# Certificate issued by apple and converted to .pem format with openSSL
# Per Apple's Push Notification Guide (end of chapter 3), first export the cert in p12 format
# openssl pkcs12 -in cert.p12 -out cert.pem -nodes 
#   when prompted "Enter Import Password:" hit return
#
cert_file = 'voip.pem'
 
host = ('gateway.push.apple.com', 2195)

data = json.dumps(payload).encode()

# convert to hex
byte_token = binascii.hexlify(device_token) # Python 3

format = '!BH32sH%ds' % len(data)
notification = struct.pack(format, 0, 32, byte_token, len(data), data)

# Create our connection using the certfile saved locally
ssl_sock = ssl.wrap_socket(socket.socket(socket.AF_INET, socket.SOCK_STREAM), certfile=cert_file)
ssl_sock.connect(host)

# Write out our data
ssl_sock.write(notification)

# Close the connection -- apple would prefer that we keep
# a connection open and push data as needed.
ssl_sock.close()