How to watch my account for transactions

Question

I am looking for an example of checking transactions that occur on my account. I read that there is a demuxjs library that supports this, but it is difficult to approach.

Clarification: I am building a trading platform. When a user orders a Buy token, they will have to send EOS to my EOS account. The part I'm building is getting that order information via EOS account and adding it to the database.

Update: I did it with demuxjs but it was slow, When I push the contract to send EOS until the demuxjs receive info 50 seconds->3 minutes in Jungle and Mainnet, Is there any way to speed up demux watch action faster?

Answer 1

If you have the cheddar, you could go for a web-socket connection.

https://www.dfuse.io/en - EOS Canada

https://eospark.com/openapi

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If not, demux is likely your best bet. For best results, you would want to host your own node or use an API endpoint that shares your need for consistent up time.

Demux isn't too difficult to implement and there are many examples out there. Basically in your app.js you specify an API endpoint that you would like to ping (the default interval is 250ms or 2 times each block).

Here's my app.js: https://github.com/NatPDeveloper/eos-chess/blob/master/app.js#L35

// DEMUX ACTION READER SETUP
const { NodeosActionReader } = require("demux-eos")
const MyActionHandler = require("./js/lib/demux-js/ActionHandler")
const { BaseActionWatcher } = require("demux")
const updaters = require("./js/lib/demux-js/updaters")
const effects = require("./js/lib/demux-js/effects") 

// LOCAL
// const actionReader = new NodeosActionReader(
//     "http://127.0.0.1:8888", // Locally hosted node needed for reasonable indexing speed
//     179000, // First actions relevant to this dapp happen at this block
// )

// JUNGLE TESTNET
const actionReader = new NodeosActionReader(
    "https://jungle.eosn.io:443", // Locally hosted node needed for reasonable indexing speed
    1196555, // First actions relevant to this dapp happens at this block
)

const actionHandler = new MyActionHandler(
    updaters,
    effects,
)

const actionWatcher = new BaseActionWatcher(
    actionReader,
    actionHandler,
    250, // Poll at twice the block interval for less latency
)

actionWatcher.watch() // Start watch loop

From there you can specify in the updaters/effects js files which contract_name:action_name you want to listen for. Upon demux picking one of those off the chain, you can pull the block data then CRUD your DB of choice. MonsterEOS uses this as does my chess-eos dapp.

demux-js: https://github.com/EOSIO/demux-js

code example (updaters/effects): https://github.com/NatPDeveloper/eos-chess/tree/master/js/lib/demux-js

block one code example: https://github.com/EOSIO/demux-js/tree/develop/examples/eos-transfers

block one simple blog example: https://github.com/EOSIO/eosio-project-demux-example

---

If you get stuck, hit up the EOS Developers channel. There are some great people in there who will help: https://t.me/joinchat/Esi1OkPktgcFeJ3Lmlcrqg

Answer 2

Like @Nat said you should use one of the provided Websocket-APIs.

https://www.dfuse.io/en

https://eospark.com/openapi

Dfuse runs very stable and very fast and it seems a lot more reliable. There are several Client-Libs available.

here https://github.com/dfuse-io and here https://github.com/cmadh/EosWsSharp