Dagger

Dagger is the best way to get realtime updates from Ethereum Blockchain. It provides a way for your DApps and Backend system to get ethereum blockchain events, like transactions, receipts and logs in realtime over websocket or socket.

We maintain infrastructure for reliable and scalable realtime events. eth-dagger is library for dagger project written in node.js and browser. It uses dagger server to get realtime updatesfrom Ethereum Network.

About dagger

Dagger helps users to develop faster and better Ethereum DApps. For more information:

Installation

# Using Yarn
yarn add eth-dagger
# Using NPM
npm install eth-dagger --save

Network

Mainnet

Websocket: wss://mainnet.dagger.matic.network
Socket: mqtts://mainnet.dagger.matic.network (You can also use `ssl://` protocol)

Kovan

Websocket: wss://kovan.dagger.matic.network
Socket: mqtts://kovan.dagger.matic.network (You can also use `ssl://` protocol)

Example

var Dagger = require("eth-dagger");
// connect to Dagger ETH main network (network id: 1) over web socket
var dagger = new Dagger("wss://mainnet.dagger.matic.network"); // dagger server
// Use mqtt protocol for node (socket)
// var dagger = new Dagger('mqtts://mainnet.dagger.matic.network'); // dagger server
// get new block as soon as it gets created
dagger.on("latest:block", function(result) {
console.log("New block created: ", result);
});
// get only block number (as it gets created)
dagger.on("latest:block.number", function(result) {
console.log("Current block number: ", result);
});

Test dagger server

This library consists woodendagger executable which is test dagger server on your local machine. So you can test with TestRPC.

Please do not use woodendagger in production. It's only for development purpose. It doesn't support removed flag.

$ woodendagger --url=https://mainnet.infura.io # or http://localhost:8545 for local json-rpc
# If you want to start dagger server on different ports,
# sockport: socket port for backend connection over TCP
# wsport: websocket port for frontend connection over websocket
$ woodendagger --url=http://localhost:8545 --sockport=1883 --wsport=1884
# To connect from dagger:
var dagger = new Dagger('mqtt://localhost:1883')

Events

Ethereum events

Every ethereum event has room, and there are two rooms: latest and confirmed. latest events are fired immediately block included in chain. confirmed events are fired after 12 confirmations.

If you want to show updates on UI in your DApp, use latest events. It will help to make UI/UX better and user friendly.

Use confirmed events for irreversible tasks from server or on UI. Like sending email, notifications or allow user to do subsequent task on UI after one transaction gets confirmed.

Every event has to start with room:

// latest block number
dagger.on("latest:block.number", function(result) {
console.log("Current block number: ", result.data);
});
// confirmed (irreversible) incoming transaction
dagger.on("confirmed:addr/0xa7447.../tx/in", function(result) {
// send email to user about new transaction she received
});
// confirmed (irreversible) contract deployment
dagger.on("confirmed:tx/0xd66169d..../receipt", function(result) {
// send notification to user saying - her contract has been deployed successfully
});

You can use wildcard for events too. There are two type of wildcards: + (for single) and # (for multiple). Use with caution as it will fetch more data then you need, and can bombard with data to your DApp.

// Listen for every outgoing transaction for any address
dagger.on('latest:addr/+/tx/out', ...)
// Triggers when 1 GNT (Golem token) get transferred to Golem multisig wallet
dagger.on('latest:log/0xa74476443119a942de498590fe1f2454d7d4ac0d/filter/0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef/+/0x7da82c7ab4771ff031b66538d2fb9b0b047f6cf9/#', ...)
// Triggers when any amount of GNT (Golem token) get sent from Golem multisig wallet
dagger.on('latest:log/0xa74476443119a942de498590fe1f2454d7d4ac0d/filter/0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef/0x7da82c7ab4771ff031b66538d2fb9b0b047f6cf9/#', ...)
// Listen for every Golem token transfer (notice `#` at the end)
dagger.on('latest:log/0xa74476443119a942de498590fe1f2454d7d4ac0d/filter/0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef/#', ...)
Ethereum eventWhen?removed flag
block.numberFor every new block number created
block.hashFor every new block hash createdYes
blockFor every new block createdYes
block/numberWhen particular block in future included in chainYes
addr/address/txOn every new transaction for addressYes
addr/address/tx/outOn every new outgoing transaction for addressYes
addr/address/tx/inOn every new incoming transaction for addressYes
tx/txIdWhen given txId included in blockYes
tx/txId/successWhen tx status is success (included in block) for txIdYes
tx/txId/failWhen tx fails (included in block) for txIdYes
tx/txId/receiptWhen receipt is generated (included in block) for txIdYes
addr/contractAddress/deployedWhen new contractAddress included in blockYes
log/contractAddressWhen new log generated for contractAddressYes
log/contractAddress/filter/topic1/topic2When new log with topic1 and topic2 generated for contractAddressYes

Dagger events

Dagger eventWhen?args
connection.statusWhen connection status changesvalue: Boolean

Event names are case-sensitive. address, txId and topics must be in lowercase.

API

new Dagger(url)

Create dagger object

  • url is a String url to connect with dagger server node. Check network section for all available url values

Example:

var dagger = new Dagger(<url>);

dagger.on(event, fn)

Subscribe to a topic

  • event is a String topic to subscribe to. event wildcard characters are supported (+ - for single level and # - for multi level)
  • fn - function (data, removed) fn will be executed when event occurred:
    • data data from event
    • removed flag saying if data is removed from blockchain due to re-organization.

dagger.once(event, fn)

Same as on but will be fired only once.

dagger.off(event, fn)

Unsubscribe from a topic

  • event is a String topic to unsubscribe from
  • fn - function (data, removed)

dagger.of(room)

Create room out of dagger. room has to be one out of two values: latest and confirmed

  • room object has following methods:
    • on same as dagger on
    • once same as dagger once
    • off same as dagger off

dagger.end([force])

Close the dagger, accepts the following options:

  • force: passing it to true will close the dagger right away. This parameter is optional.

dagger.contract(web3Contract)

Creates web3 contract wrapper to support dagger.

  • web3Contract: contract object web3. Example: new web3.eth.Contract(abi, address)

    // web3 contract
    var web3Contract = new web3.eth.Contract(abi, address);
    // dagger contract
    var contract = dagger.contract(web3Contract);
    var filter = contract.events.Transfer({
    filter: { from: "0x123456..." },
    room: "latest"
    });
    // watch
    filter.watch(function(data, removed) {
    // data.returnValues.to : address to which it has been transferred to
    // data.returnValues.value : value which has been transferred
    });
    // watch only once
    filter.watchOnce(function(data, removed) {
    // data.returnValues.to : address to which it has been transferred to
    // data.returnValues.value : value which has been transferred
    });
    // stop watching
    filter.stopWatching();

Support

If you have any queries, feedback or feature requests, feel free to reach out to us on telegram: https://t.me/maticnetwork

License

MIT