This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 857201. The European Commission assumes no responsibility for any content of this repository.

Train Resolver

Tells streaming clients from where they shall retrieve video stream segments.

What is this?

The Train Resolver service is part of the platform for media caching on trains. The Train Resolver is needed by streaming client based on the ARD-Player with the MCDN Add-on. When the user requests the playback of a video the player will first query a resolution service for which host it shall address to retrieve the respective stream segments. The DNS on trains equipped with our system will be configured to redirect these requests to the Train Resolver. The Train Resolver will tell the player to request all video segments from the local cache on the train.

How does it work?

The service consits of an HTTP interface implemented in app.controller.ts which routes to a simple provider implemented in app.service.ts. The provder generates the body of the default repsonse of the HTTP interface, which will look like in this listing:

{
  "cdns": [
    {
      "hostname": "http://<<original-CDN-hostname>>.cache.cache:8080",
      "weight": 1
    }
  ]
}

Technologie used:

• Nest.js

Install, build, run

Note: Typically you would use the up.sh script from the Platform project to install, build and run this service as part of a composite of docker services. Read on if you intend to run the service directly on your host system.

Prerequestits: Following software needs to be installed on your host machine in order to execute the subsequent steps.

• Node.js
• NPM

First, git clone this project and change into its root directory. Than run the following command to install its dependencies:

$ npm install

You can than run the service in three different modes.

# development
$ npm run start

# watch mode
$ npm run start:dev

# production mode
$ npm run start:prod

With following command you can build a docker image for this service. But again, typically you use the startup script up.sh of the Platform project to do the job.

$ docker build -t 5gv-train-resolver .