Nest Thermostat Hot Water controlled by Alexa

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For anyone that has a Nest thermostat and an Amazon Alexa, they will know there is one feature distinctly lacking. Voice boosting of the hot water. After further investigation, this is not only missing from he Alexa app but is missing from the actual API. I think that this is probably due to the function being UK only.

Initially I took to the community pages to get more information. The first post dates back to Oct ’16 and the official line was “Thanks for letting us know that this is an important feature. Duly noted! We have communicated the extremely strong interest to our development team. The request is in the queue for consideration and will be seriously considered. We value your input, and we do not discuss future schedules or internal planning in this community.” This was mid August some time. Request #1 got closed for comments and so did all other threads. #2, #3 and finally #4. As a result of this I decided to make my own.

If you want to do this, you will need the following:
– Amazon Alexa
– UK Nest Thermostat (and online account)
– IFTTT account
– Webspace to host some php files

The basics of how this works are as follows:
1. Ask Alexa to trigger an IFTTT applet. By saying “Alexa trigger …..” Alexa knows that the following commands will be passed to IFTTT. My phrase was “Alexa trigger hot water boost” Thats the IFT part.
2. Configure the applet to use webhooks that will open a php file on a server. That’s the TT part.
3. The php file calls the class and boosts the hot water for a defined time. My aim was to make this as easy to follow as possible.

The drawback of this in its current state is that there is no feedback from Alexa if it has work or even if you have said the correct thing. Any time you say “Alexa trigger ….” she responds with “sending request to IFTTT” and doesn’t even know if there is an applet that matches you request.

As a bit of a disclaimer, I have only tested on a single UK Nest on my account so cannot guarantee that it will work with any others. Provided as is with no warranty etc. Feedback would be greatly appreciated either in the comments or on GitHub.

I have everything I need, how do I do it?
Step 1: Download the files (or fork) from Github. -> https://github.com/rdiver/nest-php-api-hot-water
Step 2: Edit the example files, setting a random key and enter your nest username and password. Then upload them with the class to your webspace and make a note of the url. The key variable is purely for security reasons, so that even if someone knows the url, they cannot do anything without the key, which can be any random character set. (within reason, I would stick to A-Z a-z 0-1)
Step 3: Link Alexa and IFTTT. -> https://www.amazon.com/gp/help/customer/display.html?nodeId=201790640
Step 4: Create the applet. Its pretty easy, screen 6 outlines the options to pass the key to your web page. The example code does output all of the calls to the web pages to a file called test.txt to make it easier to debug.
(1) (2) (3)
(4) (5) (6)

Step 5: Ask Alexa to “trigger hot water boost”!

Technical Information (incase anyone wants to port to different language)
If you ended up here you probably came through the Nest Community pages where you were searching regarding the lack of Hot Water API exposure. I know that not everyone will want to use PHP so I’m going to try and break down the basics of the reverse engineering so that you can port the code to another language / platform. This is only my understanding and could totally be wrong!

So basically I worked backwards. I started by looking at the calls for boosting the hot water and found this.

As highlighted in red, I need several things to boost the hot water. Firstly I need the request url, which is also referred to as the transport url. This was already covered in the library I forked but it can be found when you log in.
Secondly I need to create the payload that can be seen above.
session: From reading this post I worked out that the session variable was not required.
op: MERGE – this is fixed.
hot_water_boost_time_to_end: This is the epooch time that you would like the boost to end.
base_object_revision & object_key: object_key is the id of your nest thermostat, and my understanding is that the website creates a snapshot of the device settings used by the website called base_object_revision. After searching through the requests (for a long time) I found one that looked promising. The website makes the following call which returns the information I need.

From the code you will see that I only request the device bucket meaning I only get the information that I need.

I tried to make the code as simple as possible, so it will be easy to use or replicate/port. Any questions please ask.

28 Comments

  • hey there. great post, something I’ve been wanting for over a year!

    I’m trying to convert to python. My first request works fine and I get the userID etc, but the second request to get the bucket data fails with a 401 unauthorized. You don’t appear to be using an authenticated connection when you do it? any ideas whay might be going wrong? I don’t know PHP – you’re posting a json payload aren’t you?
    thanks

  • Jon Andrews

    excuse the simple question…but I love that someone has been able to take what NEST cant be bothered to do and brought the much-needed functionality to the system

    I personally don’t have any web space open to me so was wondering if it is possible to host these files on a local computer, specifically an Rpi as I already have one running HA Bridge that is both running 24/7 AND a low-cost small device taking up no room

    Thnks in advance

    Jon

    • rdiver

      Hi Jon, from a quick read I think the ha-bridge may do it for you without IFTTT. But I could be wrong.
      You could in theory, put the PHP files onto the raspberry pi so that they are accessible from a url. such as http://192.168.0.11/somefolder/boostfiles.php and then add it as a custom device.
      From https://github.com/bwssytems/ha-bridge it says:
      “The Add/Edit Tab

      Another way to add a device is through the Manual Add Tab. This allows you to manually enter the name, the on and off URLs and select if there are custom handling with the type of call that can be made. This allows for control of anything that has a distinct request that can be executed so you are not limited to the Vera, Harmony, Nest or other Hue.”

      So my understanding is you could get it to call he local php files on the pi and execute through Alexa that way. Does that make sense? I’ve never used ha-bridge so the info is the result of a quick google. Hope it helps.

      • Jon Andrews

        in the process of getting this to work with HAB, I’ve installed the required files and also created the required boost.php module.

        Im not sure if I’m doing something wrong but I cannot work out how to trigger the PHP module from a command line (within my rPi) to make sure it’s working (before progressing). When I try to execute it, It responds saying access denied if I don’t append the preset key onto the command….but if I put the key on the end it doesn’t recognise the module to be run.

        Im sure Im doing something silly wrong, but as programming, in general, isn’t really my thing Im happy to put my hands up and ask for some assistance.

        • langstroth

          I can confirm the ha-bridge method does work if you don’t want to host the PHP files remotely. Essentially
          HA-Bridge (which simulates Phillips lightng hub) —-> web server ——> call to Shell script ——–> PHP script.

          In theory the bridge can call the PHP directly, but I couldn’t get it to work, so went down the shell script and simple web server (web.py) route. The set up is running on a Pi that I already had running monitoring a weather station and solar panels.

  • slicker55

    I have tried to follow these instructions very carefully but sadly, after several attempts I cannot get things to work. Alexa refers the trigger to IFTTT but the thermostat does not respond. I suspect it’s down to where my files are being hosted. Can anyone recommend a tried and tested on-line service which is free?

  • A BIG thanks to rdiver for sharing your expertise and taking the time to explain everything so clearly.
    I followed your instructions very carefully and now I can control my hot water boost using voice commands via Alexa – FANTASTIC WORK!

    • rdiver

      Glad it worked. Mines still going strong, I’m assuming that if they can be bothered to implement this, it’s unlikely they will fix my way.

  • Robert Bradley

    Fantastic implementation

    My use case is a little different, I use Home Assistant with this api to display current status and a switch to boost when needed.

    I have a bash script that invoked the call to php.

    The issue comes in that home assistant regularly checks the boost time remaining and the on off status. Nest are wise to us hammering the website and block you temporarily.

    I have witnessed this while using the api and have the error. You could test it by asking Alexa the status of the hot water a few times in a row, or running the php script a few times – though a browser probably has some sort of cookie or session persistence.

    My question: is it possible to reuse the cookie / auth key from the initial request between script calls.

    Eg a check to see if a valid cookie exists if not generate a new one

    Maybe the blocking is not the cookie and maybe it’s done on connection(DDOS protection), just a thought

    • rdiver

      Hi Rob, if you could keep the php call open then I don’t see why you couldn’t just keep calling the methods using the initial auth. PHP isn’t really suited to this though as it will timeout.


      $nest = new Nest($uname,$pwrd);
      while(1) {
      $status = getHotWaterStatus();
      sleep(10);
      }

      This would constantly poll.

  • Will P

    Hi rdiver – many thanks for this guide.

    A quick question, I’ve managed to get this set up and can hit the URL’s and receive a HTTP 200 response.

    The thing is, the boost doesn’t always come on. The same happens with my cancel boost command, I’ll get the HTTP 200 response but it didn’t actually cancel it.

    I’ve got IFTTT but at the moment I am just hitting the url in a browser to see if I can get it working but its only working now and again.

    My set up is a little different in that I have 2 nests set up on the account, one for downstairs and hot water and one for upstairs.

    On some occasions this error is thrown:

    [01-Sep-2018 16:36:16 UTC] PHP Fatal error: Uncaught exception ‘Exception’ with message ‘Error during GET of ‘/v2/mobile/user.’: malformed’ in /home/anotheri/public_html/nest/nest-php-api.php:117
    Stack trace:
    #0 /home/anotheri/public_html/nest/nest-php-api.php(84): Nest->curlGet(‘/v2/mobile/user…’)
    #1 /home/anotheri/public_html/nest/nest-php-api.php(63): Nest->getHotWaterStatus()
    #2 /home/anotheri/public_html/nest/cancel_hot_water.php(19): Nest->setHotWaterBoost(0)
    #3 {main}
    thrown in /home/anotheri/public_html/nest/nest-php-api.php on line 117

    Any ideas?? I should caveat all of this by saying I’m not an engineer or a dev!

    • rdiver

      Hi Will, when writing I do remember noting that I was not sure how it would work with 2 nests. I think you could get round this by fixing the device id.
      If you add print_r($response); to line 41 of nest-php-api.php file, and post it I might be able to offer some advice.

  • Adam

    Hi all,

    I’ve found a way to do this without using IFTTT or hosting anything. Might be an alternative to some?

    First purchase the Sonoff Basic – ​https://www.amazon.co.uk/Switch-Automation-Wireless-Control-Android/dp/B077G7FNBJ/ref=mp_s_a_1_1?ie=UTF8&qid=1536646148&sr=8-1&pi=AC_SX236_SY340_FMwebp_QL65&keywords=sonoff+basic&dpPl=1&dpID=51axPVgclDL&ref=plSrch

    Now you’ll need to give the relay a permanent supply on the input terminals but your heatlink has this already.​ Then if you follow the cable from terminal 6 of your heatlink you should find that this will connect onto the brown conductor of your hot water pump. We want to install a cable from the output of the relay to this brown core on the hot water pump (you need to keep the cable from terminal 6 installed to this core as well). This then enables the relay to energise the motor within the pump and close the connection required to turn on your hot water.

    You’ll need to install the Ewelink app and set the device up within the app, which is very simple (please note that the Sonoff connects to the 2.4ghz frequency of your router). I of course named the relay Hot Water.

    Once the app is installed you need to go into the loop timer on the bottom right​. Untick “after” and then set the time to your desired boost time in my case 1hour.

    At this stage you can test the cabling and the device are working by manually turning the relay on and off within the app. I set my boost time to 2 minutes whilst testing to ensure the relay was turned off.

    Lastly you’ll need to go into your Alexa app and install the Ewelink skill and link your account. Then add devices within the Alexa app and hey presto! “Alexa, turn on the Hot Water” and it will turn off after your pre-defined time.

    As above the Boost won’t register on the Nest as we are bypassing it.

    If anyone needs any help just let me know!

    • rdiver

      Yes this would also work. I thought about something similar for my bathroom lights as they have a fan so hue bulbs wouldn’t work. The caveat with this is it requires knowledge of (and competency with) mains electricity and this is very different to a coding solution.

  • Alan

    Hi,

    I have php 5.6.0 running in IIS on an old windows home server.
    When running the script, I get the below error in the php log (and 500 error in browser) – any idea what the problem is?

    php-api.php(63): Nest->getHotWaterStatus()
    #2 C:\example_boost_hot_water.php(18): Nest->setHotWaterBoost(60)
    #3 {main}
    thrown in C:\nest-php-api.php on line 117

    [16-Sep-2018 15:08:36 Europe/Minsk] PHP Notice: Trying to get property of non-object in C:\Program Files\Windows Server\Bin\WebApps\Site\Water\nest-php-api.php on line 30
    [16-Sep-2018 15:08:36 Europe/Minsk] PHP Notice: Trying to get property of non-object in C:\Program Files\Windows Server\Bin\WebApps\Site\Water\nest-php-api.php on line 31
    [16-Sep-2018 15:08:36 Europe/Minsk] PHP Notice: Trying to get property of non-object in C:\Program Files\Windows Server\Bin\WebApps\Site\Water\nest-php-api.php on line 32
    [16-Sep-2018 15:08:36 Europe/Minsk] PHP Notice: Trying to get property of non-object in C:\Program Files\Windows Server\Bin\WebApps\Site\Water\nest-php-api.php on line 32

    [16-Sep-2018 15:08:36 Europe/Minsk] PHP Fatal error: Uncaught exception ‘Exception’ with message ‘Error during GET of ‘/v2/mobile/user.’: malformed’ in C:\nest-php-api.php:117
    Stack trace:

    #0 C:\nest-php-api.php(84): Nest->curlGet(‘/v2/mobile/user…’)

    #1 C:\nest-php-api.php(63): Nest->getHotWaterStatus()

    #2 C:\example_boost_hot_water.php(18): Nest->setHotWaterBoost(60)

    #3 {main}
    thrown in C:\nest-php-api.php on line 117

      • Alan McCormick

        I thought that but curl appears fine (tried a few test scripts).

        phpinfo shows:

        cURL support enabled
        cURL Information 7.36.0

        and curl works from a cmd:

        C:\Users\Administrator>curl –version
        curl 7.61.1 (i386-pc-win32) libcurl/7.61.1 OpenSSL/1.1.1 (WinSSL) zlib/1.2.11 br
        otli/1.0.6 WinIDN libssh2/1.8.0 nghttp2/1.33.0
        Release-Date: 2018-09-05
        Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s
        rtsp scp sftp smb smbs smtp smtps telnet tftp
        Features: AsynchDNS IDN IPv6 Largefile SSPI Kerberos SPNEGO NTLM SSL libz brotli
        TLS-SRP HTTP2 HTTPS-proxy MultiSSL

        Time to buy a synology I think…

        • rdiver

          Ok, just had another look at your error.
          It looks like the $json doesn’t have a value and as such doesn’t get decoded.
          If you add a print_r($json) or a var_dump($json) at line 28, what does it say? (Maybe sanitise before posting!) I’m guessing that it doesn’t contain the access_token, or userid, or urls fields.

          This would lead me to believe there is a problem with the curlPost on line 24. Invalid username and password?

  • David Evans

    Hi all,

    I completed to above and works great. Where i stepped away from the above instruction was to in integrate with Smart things rather than IFTTT. This is actioned via a customer Device Handler (URI Button) which you load on via the IDE portal.

    This allows for a button on Action Tiles to be created while to can continue to use Alexa. You could also link it to a simple Z wave / Zigbee push button also.

    I also created a bespoke routine on my Alexa account so i can just say, ‘Alexa, Boost Hot Water’. Excellent work by rdiver

    Thanks

    • rdiver

      Hi David, any advice on where to look for details on creating a bespoke routine for Alexa? Boost hot water seems much better than trigger hot water boost. Would be great if I could ask Alexa if the hot water is on too!

  • cephalopod

    It’s working fantastic now, thank you so much for all your efforts! Some feedback…
    1. I had to add timezone to the DateTime call in the supplied example PHP code, or I had fatal errors causing 500s.
    2. Is there any way of using tokens or such to call the Nest API, instead of putting Nest account credentials in a PHP file which can downloaded off the website?…. bit worried about security 🙂

    Cheers rdiver!

    • rdiver

      For 1, something that I didn’t really think about was time zones, my understanding was that it ran off UTC time. Can you share your changes?
      For 2, I don’t know, I am essentially exploiting scripting of the web app, as the official API doesn’t open up hot water.
      If you were bothered, you could have the username and password passed with the call as its https.
      You could also encrypt the username and password and pass a key to make it easier. I mean non are ideal, but by passing a decryption key its only one thing to pass with the time. openssl_encrypt would probably be a good place to start.

  • Reggs11

    Just wanted to say thanks to Rdiver for this great script!
    I run a Homeseer home automation system on a dedicated windows box at home.
    There is a $30 Nest plugin available that has always lacked the ability to boost hot water (and now I understand why) to the lament of all of us UK users.
    The same Homeseer box also runs HA Bridge, so that I can run pretty much any Homeseer event with a simple call to Alexa.
    All I did to get this running was to install XAMPP server and then I created some of my own PHP scripts based on your own.
    I don’t know PHP and had to remove the ‘$access_key’ checks as none of the scripts would run (missing token error) as I assume they are for IFTTT?
    Anyway, everything is hosted locally so I then created a simple HA Bridge event so that I can say ‘Alexa, turn on the hot water’ and
    the hot water will boost for as long as I have it set to boost for in the relevant PHP script that gets called directly.
    HA Bridge can handle ‘offs’ as well very easily with direct PHP script calls.
    Great stuff Rdiver!

    • rdiver

      Hi Reggs11, thats great! Glad it worked.

      The access_key part was a validation to ensure that when the page is called, it can only be called with someone who knows the access key. Kind of like how you can only see private youtube videos or dropbox files with a link.
      The idea being, you randomly generate a key on something like https://passwordsgenerator.net that has only letters and numbers… say “g4yKkraOWtH3xHiV”. Put this as the access_key variable on the php page.
      Then when you call the page, you would do http://www.page.com/path/example_boost_hot_water.php?key=g4yKkraOWtH3xHiV and that would allow only that link to access the page. Hope that makes sense.

      It not fully secure as if not using https there are ways to get urls. Its just better than a blank URL if its being hosted on the internet and not locally.

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