SIDANWhatever / dab

Decentralized applicaton backend for Cardano.

dab

Decentralized application backend for Cardano.

About • Installation • Usage • Contributing

About

Decentralized application backend (dab) is a toolset that help developers interact with the Cardano blockchain and its smart validators.

At its core, the component called chain-watcher is following the chain looking for specific events expected by the application backend. It supports different providers to access the Cardano network.

Community

Decentralized application backend (dab) is a community project. We are releasing this minimal viable product in a modular form (at the moment it supports Blockfrost as a provider), we hope that it will gather developer community momentum and we will see many more different providers such as Oura, Koios or Ogmios emerge from the development community.

We strongly encourage community members to apply for Project Catalyst funding to make this project their own and better.

Installation

Building with Nix

Nix is the prefered way to build the chain-watcher and its components.

nix-build -A chain-watcher.components.exes.chain-watcher-blockfrost

Building with Docker

Please see docs/Docker.md.

Usage

Running the application backend demo

To run the application backend demo ⚡, do the following:

nix-shell
export BLOCKFROST_TOKEN_PATH=~/.blockfrost.testnet.token
cabal run chain-watcher-blockfrost

View the demo on http://localhost:8282/demo/index.html

Demo of demo

Client API

Register new client

To register a new client on the chain-watcher.

cid="$( curl -q -X POST -v localhost:8282/clients/new | jq -r)"

Remove client

To remove an exising client on the chain-watcher.

curl -X POST -v localhost:8282/clients/remove/${cid}

Subscribe to event

To subscribe your client to a specific event on the chain-watcher.

curl \
  -X POST \
  -H "Content-Type: application/json" \
  -v localhost:8282/clients/request/${cid} \
  --data '{"contents":"1075a1c98dbdf3486ec8f5050c84da30a057cb79ae0ce6d03d157c719c559332","tag":"TransactionStatusRequest"}'

Recurring request

To subscribe your client to a reoccuring specific event on the chain-watcher.

curl -X POST --data '{"contents":{"tag":"Ping"},"tag":"Recurring"}' -H "Content-Type: application/json" -v localhost:8282/clients/request/${cid}

Address change request

To change your address event watching.

curl -X POST --data '{"contents":"addr_test1wpzjtlyp6v4qx6gzjm4zc7lsdufw597507y060qhk84vpjsjd625n","tag":"AddressFundsRequest"}' -H "Content-Type: application/json" -v localhost:8282/clients/request/${cid}

Follow server-sent event stream

To follow on the even stream from the chain-watcher.

curl -v -N --http2 -H "Accept:text/event-stream" localhost:8282/sse/${cid}

Contributing

We are looking forward to your contributions!

💡 See Contributing and Code of conduct for more information about how to contribute your code.