New Event: COIN_BALANCE:

It's now implemented for Tendermint Protocol(will cause panics with todo for any other coins).

The way it works:

1- Subscribe to the account address using websocket
2- On any message(this means our address either sent tx or recieved tx), get the current balance
3- If the balance is changed(different than the previously broadcasted event) then broadcast it to mm2 clients.

Sample configuration:

"event_stream_configuration": {
    "access_control_allow_origin": "*",
    "active_events": {
      "NETWORK": { "stream_interval_seconds": 1.5 },
      "COIN_BALANCE": {} # stream_interval_seconds is ignored for the balance events, it's not required to define it.
    }
}

Native:

Same as #1945, for triggering COIN_BALANCE event, enable any tendermint based coin and send/recieve some funds on that address.

WASM:

Event streaming on WASM can be tested easily with https://github.com/KomodoPlatform/react-komodefi-wasm.

• Build:
  Build mm2 with wasm-pack build --release mm2src/mm2_bin_lib --target web --out-dir ../../target/target-wasm-release

• soft-linking(or file/dir replacement directly):

  atomicDEX-API/target/target-wasm-release/mm2lib.js to react-komodefi-wasm/src/js/mm2.js

  atomicDEX-API/target/target-wasm-release/snippets to react-komodefi-wasm/src/js/snippets

  atomicDEX-API/target/target-wasm-release/mm2lib_bg.wasm to react-komodefi-wasm/public/mm2_bg.wasm

• Add ATOM-TEST coin:

  Append the following json value to the coins file:

    {
    "coin": "ATOM-TEST",
    "avg_blocktime": 5,
    "protocol": {
      "type": "TENDERMINT",
      "protocol_data": {
        "decimals": 6,
        "denom": "uatom",
        "account_prefix": "cosmos",
        "chain_id": "theta-testnet-001"
      }
    },
    "derivation_path": "m/44'/118'"
  }

• Worker file:

  Create react-komodefi-wasm/worker.js file with the following content:

  self.addEventListener('message', function(event) {
    console.log(event.data);
  });

• Test the network and balance events:

  Network events should start being logged on console right away when mm2 is started, for the balance events, you have to enable tendermint based coins, an example ATOM-TEST which we added to coins file. For that, execute the following RPC:

  {
    "userpass": "testpsw",
    "method":"enable_tendermint_with_assets",
    "mmrpc":"2.0",
    "params": {
      "ticker": "ATOM-TEST",
      "tokens_params": [],
      "rpc_urls": [
    	  "https://rpc.sentry-02.theta-testnet.polypore.xyz"
      ],
      "tx_history": false
    },
    "id": 0
  }

  After the activation, when your address gets/sends TX, you should be able to see COIN_BALANCE event on the console logs.

KomodoPlatform/tokio-tungstenite-wasm

There is no socket library that supports Native + WASM platforms with async/await & Send+Sync(without those supports, handling events(specially COIN_BALANCE) will cause i/o blocking and resource-intensive situations on the runtime). I had to fork a few of the existing ones and do some changes. This fork should be super easy to maintain for us, as it's just a wrapper around tokio-tungstenite and web-sys. Most of the effort on this fork will be bumping the dependencies when needed.