README.md

CrystalBall

An Android app that streams live video feeds of IoT devices using IoT Service Blockchain.

Server

An IoT devices such as a surveillance camera can publish its media stream to the streaming server. The server is connected to the IoT Service Blockchain and listens for viewing request of streaming clients. When receive such request, the server respond a URL of the published media stream with access token for viewing through the blockchain.

Source code: server
App

The App is an IoT media streaming client which let user view the published media streams. It request stream URL and access token from the server via the IoT Service Blockchain. The user can also manage a list of connection profiles through the app for quick access.

Source code: app

Clone this repository, change working directory to crystalball

$ git clone https://github.com/nexus-lab/iot-service-blockchain-samples.git
$ cd iot-service-blockchain-samples/crystalball

Change working directory to server:
```
$ cd server
```
Install Go dependencies:
```
$ go mod download
```
Copy config.yml.example to config.yml. Fill in or change configurations according to your Hyperledger Fabric configurations. Configuration details are given in the comments.
```
$ cp config.yml.example config.yml
```
Run the server:
```
go run *.go --config config.yml
```
On your IoT device or PC that connects to the camera, publish the camera's media streams to the server. For example, you can stream your web camera with ffmpeg:
```
ffmpeg -f v4l2 -framerate 10 -video_size 1280x720 -input_format mjpeg -i <camera_device_name> -vcodec libx264 \
        -f flv rtmp://<streaming_server_address>/?key=<streaming_key>
```
<camera_device_name> is the device name of your camera. <streaming_service_address> is the listening public address of your server. It could be the external_addr set in the config.yml file. <streaming_key> is the key you set in the config.yml file.

You can also publish a dummy video to the server for testing:
```
ffmpeg -re -i dummy.flv -c copy -f flv rtmp://<streaming_server_address>/?key=<streaming_key>
```

Change working directory to app:
```
$ cd app
```
You will need to authenticate to GitHub Packages using a personal access token. Read this for details. After creating your personal access token, copy github.properties.example to github.properties and put your GitHub user name and token there:
```
cp github.properties.example github.properties
```
Compile and package the app using Android Studio or Gradle CLI.
Install and run the app in an Android device or emulator.
Open the Settings page from the top right gear icon and fill in your Hyperledger Fabric user identity information, gateway information, and IoT Service Blockchain chaincode information. Those information may be different from the credentials used by the server's config.yml. Additionally, you can import or export settings from/to a JSON file.
Tap on the add icon on the home page and add a new service by its organization ID, device ID, and service name. You can also add a service by scanning its QR code on the IoT Service Blockchain Explorer website.
Once a service is added, you can review its details and play its video feed.