Chromecast devices

Dashkiosk can optionnaly handle Chromecast devices. When the support is enabled (see Available options), Dashkiosk will be able to discover Chromecast devices on the network.


Due to the closedness of the Chromecast platform, its support in Dashkiosk may break from time to time. The Chromecast devices are updating themselves without user consent. Moreover, the resources allocated to the web browsers are limited and it may be difficult for them to display complex dashboards. Therefore, it is better to rely on alternative solutions, like the Android app (which also has some drawbacks) or the web receiver.


To be able to handle Chromecast devices, you need to enable its support (see Available options). You also need to ensure that mDNS is working correctly on your setup.

When starting Dashkiosk, you may get this error message:

*** WARNING *** The program 'nodejs' called 'DNSServiceRegister()' which is not supported (or only supported partially) in the Apple Bonjour compatibility layer of Avahi.
*** WARNING *** Please fix your application to use the native API of Avahi!

This is perfectly harmless.

For Linux, use the following command to check that you can see The Chromecast devices:

$ avahi-browse _googlecast._tcp
+ eth0.20 IPv4 Chromecast Here              _googlecast._tcp     local
+ eth0.20 IPv4 Chromecast Demo              _googlecast._tcp     local

If this first step doesn’t work, check you have Avahi installed and running. Usually, this can be done with apt-get install avahi-daemon. Then, check you don’t have any firewall preventing multicast traffic to port 5353.

Please note that you need to be on the same network as the Chromecast devices 1.

Then, check that you can resolve the Chromecast names:

$ getent hosts "Chromecast\032Here".local    Chromecast\032Here.local

If this doesn’t work, you need to configure your resolver to use multicast DNS. This is usually done by putting the following line in /etc/nsswitch.conf:

hosts: files mdns4_minimal [NOTFOUND=return] dns mdns4

On OS X, you can check if you can see the Chromecast devices with dns-sd -B _googlecast._tcp, then try to resolve with dns-sd -G v4 "Chromecast\032Here".local.


Discovered Chromecast devices will be assigned to the special group “Chromecast devices”. This group has no dashboard on purpose: if a Chromecast device is on a group with a dashboard, Dashkiosk will wait for the Chromecast device to be on the home screen and starts a custom receiver which will load the regular receiver and turn your Chromecast device into a regular display.

You can either add dashboards to the “Chromecast devices” group to let all Chromecast devices display a dashboard on inactivity or move the selected Chromecast devices to another group.

Custom receiver

To display dashboards, a Chromecast device is requested to run a custom receiver, which is just some HTML5 application. Unfortunately, we cannot just provide an URL for that, we have to give an application ID. The Chromecast device will ask Google which URL to use and Google will provide the URL. By default, Dashkiosk will use an application hosted on some GitHub URL. This should work just fine.

If you want to use your own custom receiver (or modify the existing one), you need to declare a new application (and pay US$ 5). That’s a bit unfortunate. Maybe we could do an application that will just forward to another application.


Let me explain how the whole thing works.

  1. Dashkiosk detects the Chromecast device using multicast DNS. If it doesn’t see yours, you need to check that multicast is correctly working on your network.

  2. If the Chromecast is in a group with dashboards, Dashkiosk then asks to load the custom receiver using its application ID (5E7A2C2C). The Chromecast will then ask Google which URL it should load for this application ID. Google will send back the GitHub URL hosting the custom receiver. The Chromecast will load it. You should get a screen “This, Jen, is the Internet”.

  3. Dashkiosk will send the receiver URL, as you configured it in the Available options (or with --chromecast.receiver). Once the custom receiver gets this URL, it displays it in the lower left part of the screen. If it isn’t displayed, it is likely to be a bug in Dashkiosk. Have a look in the logs and open an issue.

  4. The custom receiver will then load the regular receiver. If you don’t get to this step and are stuck on the “This, Jen, is the Internet” screen, it means that your Chromecast is not able to retrieve the receiver you provided. It could be a firewall issue or a DNS issue. Try to connect your laptop on the same network as the Chromecast and load the receiver URL yourself to see what is happening.

Troubleshooting is quite complex. Due to a recent change, users are only allowed to debug their own application. You need to register your Chromecast and register and host a copy of the Chromecast receiver. You’ll get an ID for the Chromecast application and should use to specify it.

Once the application is running, you can connect to your Chromecast device using its IP on port 9222. The Chromecast needs to be running the custom receiver. With recent versions of Chrome, you are likely to get mixed content restrictions. Click on the shield in the URL bar to lift this restriction.

Also, the Chromecast is a low-end device (but quite capable): it may have difficulties to display complex dashboards. You may want to try to load the dashboard alone using a simple sender. If the dashboard is unable to render correctly even with this sender, try to reduce its complexity. Moreover, during transitions, the Chromecast has to be able to display the current dashboard while the next one is rendered in the background. This may use too much resources. Try to not load two consecutive complex dashboards.



The mDNS packets are usually using a TTL of 1 and therefore cannot be routed even if you try to setup multicast routing on your network. The correct solution is to configure a DNS-SD name server.