Scripting: Bashing IoT
scott.murphy@arrow-eye.com
2018-12-06
Bash scripting for the win...
Presenter Notes
Announcements
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Welcome to OCLUG
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OCLUG was founded in March, 1997. Its membership is diverse, ranging from people without computer knowledge to proverbial gurus. OCLUG was created to help promote Linux in the Ottawa area. We maintain several mailing lists, to help accomplish this goal and to provide technical support. OCLUG holds monthly general meetings.
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Presenter Notes
So... Welcome to Linux-Ottawa
aka OCLUG
We have a few preliminary items to go over before we start the actual talks.
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Presenter Notes
Venue Notes
As you know, given that you are here, we have yet another venue this month.
I'm not sure where we will be next month, as I have not found a good venue for an extended trial. Centerponte seems to be OK, but it is booked on our night for all of 2019. We'll see how this room does, but it does have the 20:30 end of night, so we may have to consider a different location. On the other hand, this does allow for an earlier trip to a pub.
I'm open to suggestions that are not very expensive.
Presenter Notes
Normal Meeting format
- 18:00 - 19:00 : New2Linux hour
- 19:00 - 21:00 : Main talk(s)
- Typical format
- Opening comments (like these)
- Usually a shorter talk
- Short break while switching speakers
- A longer talk with questions
- Typical format
- 21:00 - 21:15 : Wrap up, decision on if there will be a post meeting event
- 21:30 - Done : Beer Sig (social event)
As you can see, this may need adjustment due to venue restrictions.
Presenter Notes
We now return to our regularly scheduled talk
Presenter Notes
Our target IoT device
How many of you have WeMo units?
Presenter Notes
Belkin WeMo devices
Belkin produces a set of IoT devices for home automation.
The popular ones are wall plugs and light switches. They have added a power utilization wall plug, a dimmer unit, as well as a crock pot unit. They also updated the wall unit from the one I have to a slimmer unit.
I have one of the original plugs here to pass around.
Presenter Notes
Control
The short configuration method is:
- Plug the unit in.
- Join the newly visible access point it creates via the app.
- Provide credentials for your wireless network through the app.
- It will join your network and also attempt to configure remote access. This you can disable after the fact.
- You can now controll it via the app.
Seems simple enough, right?
Presenter Notes
Not quite
The app is only available for IOS or Android. You can't control them from your desktop.
That doesn't sound too bad now does it?
What if you...
- want to use them with your own home automation?
- want to gather the state of all your switches and show them?
- just want to turn on or off something from your desktop system?
- etc.
Presenter Notes
You can!
It is remarkably easy to do so, as long as you don't mind a bit of scripting.
With a little bash and curl, you can get the devices to perform their tasks without having to get your phone or tablet out.
Of course, this can only happen after they have been configured with the app.
(Other methods are possible, but that is something we can save for a future talk).
Presenter Notes
A WeMo Script
We will examine the script I have been using. I had a simpler one, but I ran across this one.
1 #!/bin/bash
2
3 USAGE="wemo.sh [IP|network] [on|off|getstate|getsignal|getname|find]"
4
5 if [[ $# -ne 2 ]] ; then
6 echo "$USAGE"
7 exit 0
8 fi
9
10 IP="$1"
11 CMD="$2"
12
13
14 # Wemo devices typically listen on 49152 or 49153, we need to test for that
15
16 getPort () {
17 PORTTEST=$(curl -s "$IP":49152 | grep "404")
18
19 if [ "$PORTTEST" = "" ] ; then
20 PORT=49153
21 else
22 PORT=49152
23 fi
24 }
Presenter Notes
Script Page 2
1 turnON () {
2 getPort
3 curl -0 -A '' -X POST -H 'Accept: ' -H \
4 'Content-type: text/xml; charset="utf-8"' -H \
5 "SOAPACTION: \"urn:Belkin:service:basicevent:1#SetBinaryState\"" --data \
6 '<?xml version="1.0" encoding="utf-8"?>
7 <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
8 s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
9 <s:Body><u:SetBinaryState xmlns:u="urn:Belkin:service:basicevent:1">
10 <BinaryState>1</BinaryState></u:SetBinaryState></s:Body>
11 </s:Envelope>' \
12 -s http://$IP:$PORT/upnp/control/basicevent1 | grep "<BinaryState" | cut -d">" \
13 -f2 | cut -d "<" -f1 | sed 's/0/OFF/g' | sed 's/1/ON/g'
14 }
Presenter Notes
Script Page 3
1 turnOFF () {
2 getPort
3 curl -0 -A '' -X POST -H 'Accept: ' -H \
4 'Content-type: text/xml; charset="utf-8"' -H \
5 "SOAPACTION: \"urn:Belkin:service:basicevent:1#SetBinaryState\"" --data \
6 '<?xml version="1.0" encoding="utf-8"?>
7 <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
8 s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
9 <s:Body><u:SetBinaryState xmlns:u="urn:Belkin:service:basicevent:1">
10 <BinaryState>0</BinaryState></u:SetBinaryState></s:Body>
11 </s:Envelope>' \
12 -s http://$IP:$PORT/upnp/control/basicevent1 | grep "<BinaryState" | cut -d">" \
13 -f2 | cut -d "<" -f1 | sed 's/0/OFF/g' | sed 's/1/ON/g'
14 }
Presenter Notes
Script Page 4
1 getName () {
2 getPort
3 curl -0 -A '' -X POST -H 'Accept: ' -H \
4 'Content-type: text/xml; charset="utf-8"' -H \
5 "SOAPACTION: \"urn:Belkin:service:basicevent:1#GetFriendlyName\"" --data \
6 '<?xml version="1.0" encoding="utf-8"?>
7 <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
8 s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
9 <s:Body><u:GetFriendlyName xmlns:u="urn:Belkin:service:basicevent:1">
10 <FriendlyName></FriendlyName></u:GetFriendlyName></s:Body>
11 </s:Envelope>' \
12 -s http://$IP:$PORT/upnp/control/basicevent1 | grep "<FriendlyName" | cut \
13 -d">" -f2 | cut -d "<" -f1
14 }
Presenter Notes
Script Page 5
1 getState () {
2 getPort
3 curl -0 -A '' -X POST -H 'Accept: ' -H \
4 'Content-type: text/xml; charset="utf-8"' -H \
5 "SOAPACTION: \"urn:Belkin:service:basicevent:1#GetBinaryState\"" --data \
6 '<?xml version="1.0" encoding="utf-8"?><s:Envelope
7 xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
8 s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
9 <s:Body><u:GetBinaryState xmlns:u="urn:Belkin:service:basicevent:1">
10 <BinaryState>1</BinaryState></u:GetBinaryState></s:Body></s:Envelope>' \
11 -s http://$IP:$PORT/upnp/control/basicevent1 | grep "<BinaryState" | cut \
12 -d">" -f2 | cut -d "<" -f1 | sed 's/0/OFF/g' | sed 's/1/ON/g'
13 }
Presenter Notes
Script Page 6
1 getSigStrength () {
2 getPort
3 curl -0 -A '' -X POST -H 'Accept: ' -H \
4 'Content-type: text/xml; charset="utf-8"' -H \
5 "SOAPACTION: \"urn:Belkin:service:basicevent:1#GetSignalStrength\"" --data \
6 '<?xml version="1.0" encoding="utf-8"?>
7 <s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/"
8 s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/">
9 <s:Body><u:GetSignalStrength xmlns:u="urn:Belkin:service:basicevent:1">
10 <GetSignalStrength>0</GetSignalStrength></u:GetSignalStrength></s:Body></s:Envelope>' \
11 -s http://$IP:$PORT/upnp/control/basicevent1 | grep "<SignalStrength" | cut \
12 -d">" -f2 | cut -d "<" -f1
13 }
Presenter Notes
Script Page 7
1 findDevices () {
2 which nmap > /dev/null || \
3 ( echo "nmap is not installed and it's needed for this option" ; exit 1 )
4
5 echo "$IP" | grep -q '\*'
6 if [[ $? -ne 0 ]] ; then
7 echo "You need to provide a network for this option. It should be similar to 1.1.1.*"
8 exit 1
9 fi
10
11 echo "Finding. This may take a while..."
12 DEVICES=$(nmap -p 49153 --open "$IP" | grep 'scan report for' | awk '{print $5}')
13 if [ "$DEVICES" ] ; then
14 echo "IP NAME"
15 echo "---------------------"
16 for DEVICE in $DEVICES ; do
17 IP="$DEVICE"
18 echo "$DEVICE $(getName )"
19 done
20 else
21 echo "Did not find any devices"
22 fi
23 echo ""
24 }
Presenter Notes
Script page 8
1 case "$CMD" in
2 on) turnON ;;
3 off) turnOFF ;;
4 getstate) getState ;;
5 getsignal) getSigStrength ;;
6 getname) getName ;;
7 find) findDevices ;;
8 *) echo "Unknown option" && exit 1 ;;
9 esac
10
11 exit 0
Presenter Notes
Let's examine a script run
As you can see below, if you happen to know how many are out there, you can run the find command a few times to get a proper list. I think they need to be strobed a few times to make them responsive.
$ wemo 192.168.1.* find
Finding. This may take a while...
IP NAME
---------------------
192.168.1.81 BackDeck
$ wemo 192.168.1.* find
Finding. This may take a while...
IP NAME
---------------------
192.168.1.81 BackDeck
192.168.1.84 Front Lamp
$ wemo 192.168.1.* find
Finding. This may take a while...
IP NAME
---------------------
192.168.1.80 Front Light
192.168.1.81 BackDeck
192.168.1.82 Guest Room
192.168.1.84 Front Lamp
Presenter Notes
Script run (continued)
$ wemo 10.9.8.84 getstate
ON
$ wemo 10.9.8.81 getstate
OFF
$ wemo 10.9.8.81 on
ON
$ wemo 10.9.8.81 getstate
ON
$ wemo 10.9.8.81 off
OFF
$ wemo 10.9.8.81 getstate
OFF
$ wemo 10.9.8.81 getsignal
89
$ for i in 80 81 82 84; do
> wemo 10.9.8.${i} getsignal
> done
76
89
91
99
$