Alexa Chromecast Skill

Allows Amazon Alexa to control your Google Chromecast

This skill supports controlling a single Chromecast or multiple Chromecasts in different rooms. Each Alexa device can be set to control a different room. This is done by matching the room name to your Chromecast device's name. E.g. If your Chromecast is named: "Master Bedroom TV", then set the Alexa room to control to "Master Bedroom"

The following will then pause the Chromecast in the Master Bedroom:

Alexa, ask Chromecast to pause

You can control another room by saying something like:

Alexa, ask the Chromecast to pause in the Media Room

To change the room a particular Alexa device controls you can say:

Alexa, ask the Chromecast to set the room

Standard commands

The following media commands are available:

 VOICE COMMAND         ACTION
 --------------------------------------------------------------------------------
 pause                 -> Pause a playing item
 play                  -> Play a paused item
 stop                  -> Stop the currently playing item
 set volume to 5       -> Change the volume between 0 and 10
 mute                  -> mute the volume
 unmute                -> unmute the volume
 rewind                -> Rewind back 15 seconds ("skip back" or "go back" also work)
 rewind 30 seconds     -> Rewind back 30 seconds
 fast forward          -> Fast forward 15 seconds ("skip forward" or "go forward" also work) 
 fast forward 1 minute -> Fast forward 1 minute
 restart               -> Restarts the media item from the beginning
 next                  -> Play or show the next item
 previous              -> Play or show the previous item
 open {app}            -> Open a specific app. Plex and YouTube are supported.

NOTE: Stop doesn't work as expected on the Netflix app and will quit the app instead.

YouTube app commands

Play items on YouTube.

 VOICE COMMAND        ACTION
 --------------------------------------------------------------------------------
 play/find {title}                 -> Play videos matching the title
 play/find videos of {title}       -> Play videos matching the title
 play/find the trailer for {title} -> Play trailers matching title
 play/find the show {title}        -> Play a Youtube show matching the title
 play/find the movie {title}       -> Play a Youtube movie matching the title
 play/find the song {title}        -> Play a song matching the title
 play/find the album {title}       -> Play an album matching the title
 play/find the playlist {title}    -> Play a playlist matching the title
 play/find songs by {artist}       -> Play songs by the specified artist

Plex app commands

Find and play items on your Plex server.

 VOICE COMMAND                    ACTION
 ---------------------------------------------------------------------------------
 play                             -> Resumes from pause, or plays the displayed item
 stop                             -> Stops playing and displays the item details
 play/find {title}                -> Play/Find the title
 play/find the video {title}      -> Play/Find the title
 play/find the tv show {title}    -> Play/Find a tv show matching the title
 play/find the movie {title}      -> Play/Find a movie matching the title
 
 play the song {title}            -> Play a song matching the title
 play/find the album {title}      -> Play/Find an album matching the title
 shuffle the album {title}        -> Play an album matching the title in shuffled order
 play/find songs by {artist}      -> Play/Find songs by the specified artist
 shuffle songs by {artist}        -> Play songs by the specified artist in shuffled order
 play/find the playlist {title}   -> Play/Find a playlist matching the title
 
 play/shuffle photos from {year}          -> Play/Shuffle photos from the specified year
 play/shuffle photos from {month} {year}  -> Play/Shuffle photos from the specified month and year
 play/shuffle photos from {title}         -> Play/Shuffle photos from albums matching the title
 
 set/change quality to {level}    -> Transcode the media to "low" (480p), "medium" (720p), "high" (1080p) or "maximum".
 raise/lower the quality          -> Increase or lower the video quality from the current setting
 turn on subtitles                -> Turns on subtitles in the configurged language
 turn off subtitles               -> Turns off subtitles
 switch audio                     -> Switches to another audio track if available (e.g. to the directors commentry)
 
 play/find the episode {title} of {show}    -> Play/Find the specified show episode by the title
 play/find season {#} episode {#} of {show} -> Play/Find the specified show episode by the season and episode number

Example Commands

Alexa, ask Chromecast to pause

Alexa, ask Chromecast to resume

Alexa, ask Chromecast to rewind 2 minutes

Alexa, ask Chromecast to play Mythic Quest on Plex

Alexa, ask Chromecast to play The Matrix trailer

How it works

Alexa skills run in the cloud, but this skill needs to be on your local network to control the Chromecast. This skill implements a hybrid approach: the command is handled by Alexa on AWS, which sends a notification to your local server.

The Lambda component is in src/lambda, and the local component is in src/local.

Both the Chromecast and the Raspberry Pi (or whatever the local notification handler will run on) MUST be on the same network in order for the Chromecast to be discoverable.

Dependencies

Installation requires a UNIX environment with:

BASH
Python 3.7
Pip

Setup and installation

Build the AWS Lambda Function

Create an Amazon Web Services account
Run aws-setup.sh to create a Role, Lambda Function, and SNS Topic. (It will run aws configure, so have an key id and access key ready)

Setup the Alexa Skill

Go to ASK Console and choose "Create Skill"
Select "Custom" and "Provision your own", then click "Create skill". On the template screen just use the "Hello World Skill" template
Click on "Interaction Model" in the left menu, then "JSON Editor"
Copy and paste the content from config/en/interaction_model.json into the editor, then click "Save Model"
Click on "Endpoint" in the left menu. Enter the Lambda function ARN by the aws-setup.sh. Click "Save Endpoints"
Click on "Invocation" in the left menu. Click on "Build Model"
Click on the "Test" tab. Enter

Install the local application which control the Chromecasts

Install local dependencies with sudo pip3 install -r ./src/local/requirements.txt
Run ./start.sh to start the listener, or ./docker-start.sh to run in an interactive docker session. Or ./docker-start.sh -d to run as a service. The service attempts to AWS SNS using UPNP. If UPNP is disabled in your network you can specify a port. ./start.sh -p 30000 To see other options run ./start.sh -h or ./docker-start.sh -h.

When run you should see something like the following:

2020-07-12 11:10:40,688 - root - INFO - Starting Alexa Chromecast listener...
2020-07-12 11:10:40,688 - local.ChromecastSkill - INFO - Finding Chromecasts...
2020-07-12 11:10:45,696 - pychromecast - INFO - Querying device status
2020-07-12 11:10:45,727 - pychromecast - INFO - Querying device status
2020-07-12 11:10:45,767 - local.ChromecastSkill - INFO - Found Media Room TV
2020-07-12 11:10:45,768 - local.ChromecastSkill - INFO - Found Living Room TV
2020-07-12 11:10:45,769 - local.ChromecastSkill - INFO - 2 Chromecasts found
2020-07-12 11:10:45,809 - botocore.credentials - INFO - Found credentials in environment variables.
2020-07-12 11:10:46,967 - local.SkillSubscriber - INFO - Listening on http://123.123.123.123:30000
2020-07-12 11:10:46,968 - local.SkillSubscriber - INFO - Subscribing for Alexa commands...
2020-07-12 11:10:47,344 - local.SkillSubscriber - INFO - Received subscription confirmation...
2020-07-12 11:10:47,431 - local.SkillSubscriber - INFO - Subscribed.

Setup the Chromecast that Alexa will control

Say "Alexa ask Chromecast to play" The skill will take you through any required room setup.

Setup connection to Youtube

After running the skill as below .custom_env file will be created.

Fill out the required Youtube API Key to allow the skill to connect to Youtube.

To get a key follow the instructions here: https://sns-sdks.lkhardy.cn/python-youtube/getting_started/

Setup connection to Plex

Fill out the required Plex variables to allow the skill to connect to Plex.

To get the required token https://support.plex.tv/articles/204059436-finding-an-authentication-token-x-plex-token/

Running Alexa Chromecast Skill

Shell example

./start.sh

Docker

The skill subscriber can be run with docker:

./docker-start.sh - for an interactive session ./docker-start.sh -d - to run as a service

Environment variables

The skill subscriber (local) uses these environment variables:

AWS_SNS_TOPIC_ARN - AWS SNS Topic ARN (can be found in the .env file after running aws-setup.sh)
AWS_ACCESS_KEY_ID - AWS User Access Key
AWS_SECRET_ACCESS_KEY - AWS Secret Access Key
AWS_DEFAULT_REGION - AWS Lambda and SNS Region (e.g. eu-west-1)

If you have run aws configure, you will not need to set AWS_ACCESS_KEY_ID, AWS_SECRET_ACCESS_KEY, or AWS_DEFAULT_REGION.

Supporting Scripts

aws-setup.sh

Sets up an AWS environment for the Alexa Skill:

Creates an IAM role for Alexa (with permissions for SNS)
Creates an SNS topic to communicate over
Creates an S3 persistent store for persisting the room to Alexa device mapping
Creates a Lambda function

build-lambda-bundle.sh

Creates a lambda-bundle.zip, which can be uploaded to an AWS Lambda function.

aws-update-lambda.sh

Runs build-lambda-bundle and automatically uploads the bundle to AWS Lambda.

FAQ

No Chromecasts found

When the local service starts it searches for Chromecasts on the network. If there are no ChromeCasts found, it will exit. To fix this, you must confirm that the Chromecast is on and working, make sure you can access it from your phone, and make sure that everything is on the same network. To debug, a tool to search and list found ChomeCasts is provided at ./search-chromecasts (make sure to make it executable with chmod +x ./search-chromecasts).

Local listener fails to subscribe

If the local listener fails to subscribe (no subscribe messages or an error) then the Chromecasts won't receive commands from Alexa By default the local listener uses UPNP and a dynamic port to establish an external connection, you can override this if required.

Check UPNP is enabled/allowed on your network
If UPNP is not enabled or working try and manually specify a port, and ensure your firewall/router is configured to allow external access to this port e.g. to use port 30000 run ./start.sh -p 30000 or ./docker-start.sh -p 30000
Log into the AWS console and check the SNS topic is setup, and check the Cloud Watch logs for your the lambda function for any errors.

Alexa had an error launching the skill or processing a command

Try redeploying the lambda skill. ./aws-update-lambda.sh
If that didn't work go to the AWS Console and check the CloudWatch logs associated with the lambda function

Alexa accepted the command but it didn't seem to work

Check the local listener output, it should show the received command and any error that was encountered
To check the docker service logs run something like docker logs alexa_chromecast --since=30m, which shows the logs for the last 30 minutes
If the command wasn't received then try restarting the service. Consider scheduling a daily restart if it's a common issue. e.g. docker restart alexa_chromecast

jinxo13/Alexa-Chromecast-Skill-2.0