Instructions for setting up a Raspberry Pi Zero to send an iOS push notification when network interfaces go 'up'

gistfile1.txt

###Sending Push notifications from Raspberry Pi when network interfaces go online. 
- @kosso

- Apple : Set up app ID with Push Notifications cert.
- Download the .p12 CERT and KEY files

via: http://blog.raminrakhamimov.com/?p=81

Convert the p12 files to PEM format with:

# CERT
    
    openssl pkcs12 -clcerts -nokeys -out apns-dev-cert.pem -in apns-dev-cert.p12

# KEY

    openssl pkcs12 -nocerts -out apns-dev-key.pem -in apns-dev-key.p12

# STRIP PASSWORD FROM KEY

    openssl rsa -in apns-dev-key.pem -out apns-dev-key-noenc.pem

# COMBINE CERT AND KEY as single .pem

    cat apns-dev-cert.pem apns-dev-key-noenc.pem > apns-dev.pem


# Install pyapns Twistd etc. 

    sudo apt-get install libffi-dev
    sudo apt-get install libssl-dev
    sudo easy_install cryptography
    sudo easy_install pyopenssl
    sudo easy_install service_identity
    sudo easy_install python-epoll
    sudo easy_install pyapns 

# The latest (17.x) Twisted version does work with pyapns! https://github.com/samuraisam/pyapns/issues/83

    sudo pip install Twisted==16.1.1


# To start Twistd : 

    sudo twistd -r epoll web --class=pyapns.server.APNSServer --port=7077

# (creates .pid file in current directory)

# To stop Twistd :

    sudo kill -9 `sudo cat twistd.pid`


# send_push.py - usage:  ./send_push.py "hello world!"
----------------------------------------------------------------

    #!/usr/bin/python
    import sys
    from pyapns import configure, provision, notify, feedback
    
    print 'Send message :', sys.argv[1]
    alert_text = sys.argv[1]
    # Get Device token from an iOS app registration for notifications.
    device = "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
    
    # Same port as twistd 
    configure({'HOST': 'http://localhost:7077/'})
    
    def provision_callback(e):
        print 'called provision_callback '+str(e)
    
    def provision_errback(e):
        print 'called provision_errback : '+str(e)
    
    def notify_callback(e):
        print 'called notify_callback '+str(e)
    
    def notify_errback(e):
        print 'called notify_errback : '+str(e)
    
    # This is the Development 'sandbox' Cert. Use 'production' for a live app.
    provision('sand_pizero1', open('/path/to/combined/cert/and/key/apns-dev.pem').read(), 'sandbox', async=True, callback=provision_callback, errback=provision_errback)
    
    # Send it! 
    notify('sand_pizero1', device, {'aps':{'alert': alert_text}}, async=False, callback=notify_callback, errback=notify_errback)
    

-----------------------------------------------------------------


### Detecting when network interfaces go 'up'

Create a script to [stop]/start twistd:

    #!/bin/bash
    # Kill it first just in case or port will remain in use
    cd /to/path/where/twistd.pid will live
    sudo kill -9 `sudo cat /path/to/twistd.pid`
    sudo twistd -r epoll web --class=pyapns.server.APNSServer --port=7077

Execute this in /etc/rc.local by adding this line to trigger on boot up:

    sudo /bin/bash /path/to/your/startstop/script/start_twistd.sh

Create a script to trigger when an interface goes up:
!/bin/bash
# to run when the a network interface goes up
# triggered in /etc/network/interfaces - see below
# @Kosso

echo "interface went up.. restart twistd ..." >> /home/pi/post-up.log

# cd to a directory which will keep the .pid file
cd /home/pi/_PUSH
sudo kill -9 `sudo cat twistd.pid`
sleep 3
sudo twistd -r epoll web --class=pyapns.server.APNSServer --port=7077

echo "WLAN ok. start pinger.." >> /home/pi/post-up.log 

# should probably count this and set a limit
while ! ping -c 1 -W 1 8.8.8.8; do
    echo "WLAN Waiting for 8.8.8.8 - network interface might be down..." >> /home/pi/post-up.log
    sleep 1
done

HOST=`hostname`
echo "WLAN GETTING EXTERNAL IP....." 
DATE=`date +%Y-%m-%d:%H:%M:%S`
LOCALIP=`hostname --all-ip-addresses`
WANIP=`wget -qO- http://ipecho.net/plain ; echo`

echo "$DATE : WLAN0 : $HOST ONLINE $LOCALIP - external: $WANIP" >> /home/pi/post-up.log

sleep 3
SEND_PUSH=`/home/pi/_PUSH/send_push.py "$DATE :WLAN0: $HOST ONLINE $LOCALIP - external: $WANIP"`

-------------------

Edit:  /etc/network/interfaces to trigger script: 


    # Include files from /etc/network/interfaces.d:
    source-directory /etc/network/interfaces.d
    
    auto lo
    iface lo inet loopback
    
    # On a Pi Zero, I use this to detect when a USB iPhone hotspot is detected.
    # See here for how to do that: https://www.daveconroy.com/how-to-tether-your-raspberry-pi-with-your-iphone-5/
    allow-hotplug eth0
    iface eth0 inet dhcp
    up bash /home/pi/_PUSH/_eth0_up.sh
    
    # Detect Wifi up
    allow-hotplug wlan0
    iface wlan0 inet manual
    wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
    up bash /home/pi/_PUSH/_wlan0_up.sh