SignumJS
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Show attached messages

This example demonstrates how to read attached messages (not enrcrypted)

PreviousList TransactionsNextSend Signa

Last updated 3 years ago

In the basic examples we still show how to use SignumJS depending the way you are using SignumJS, i.e. imported via NodeJS package manager or as minified bundle. In case you haven't read about the module system, take a quick look there:

A fully working example is available

Following functions from SignumJS are used in this example

  • function to create the api instance

  • function to fetch the transactions from the blockchain

  • function to check, whether a message is encrypted or not.

  • enums to filter for the specific message types

  • Value Object to parse and convert the given address

  • Value Object to convert between blockchain timestamp and real date

const {
    composeApi,
    isAttachmentVersion,
    TransactionType,
    TransactionArbitrarySubtype, 
    Address
} = require('@signumjs/core');
const {ChainTime} = require('@signumjs/util')

// Create the Api instance to connect to a blockchain node
const api = composeApi({
    nodeHost: "https://europe.signum.network"
});

// here we check for a certain attachment type, and get the text message if not encrypted
const getMessageText = transaction =>
    isAttachmentVersion(transaction, 'EncryptedMessage')
        ? '<encrypted>'
        : transaction.attachment.message;

async function listMessages(account) {
    try {
        const accountId = Address.create(account).getNumericId()

        // here we can explicitly filter by Transaction Types
        const {transactions} = await api.account.getAccountTransactions(
            {
                accountId,
                lastIndex: 20, // getting only the most recent 20
                type: TransactionType.Arbitrary,
                subtype: TransactionArbitrarySubtype.Message
            }
        );

        // now we iterate through the transactions and print in a formatted way
        transactions.forEach(t => {
            console.info(`On ${ChainTime.fromChainTimestamp(t.blockTimestamp).getDate()}`)
            console.info(`From ${t.senderRS}`)
            console.info(`To ${t.recipientRS}`)
            console.info('Message:\n', getMessageText(t), '\n---')
        })

    } catch (e) {
        handleError(e)
    }
}
import {
    composeApi,
    isAttachmentVersion,
    TransactionType,
    TransactionArbitrarySubtype, 
    Address,
    Transaction
} from '@signumjs/core';
import {ChainTime} from '@signumjs/util'

// Create the Api instance to connect to a blockchain node
const api = composeApi({
    nodeHost: "https://europe.signum.network"
});

// here we check for a certain attachment type, and get the text message if not encrypted
const getMessageText = (transaction: Transaction): string =>
    isAttachmentVersion(transaction, 'EncryptedMessage')
        ? '<encrypted>'
        : transaction.attachment.message;

async function listMessages(account: string): Promise<void> {
    try {
        const accountId = Address.create(account).getNumericId()

        // here we can explicitly filter by Transaction Types
        const {transactions} = await api.account.getAccountTransactions(
            {
                accountId,
                lastIndex: 20, // getting only the most recent 20
                type: TransactionType.Arbitrary,
                subtype: TransactionArbitrarySubtype.Message
            }
        );

        // now we iterate through the transactions and print in a formatted way
        transactions.forEach(t => {
            console.info(`On ${ChainTime.fromChainTimestamp(t.blockTimestamp).getDate()}`)
            console.info(`From ${t.senderRS}`)
            console.info(`To ${t.recipientRS}`)
            console.info('Message:\n', getMessageText(t), '\n---')
        })

    } catch (e:any) {
        console.log(e)
    }
}
// you need to have imported in your index.html:
/*
<script src='https://cdn.jsdelivr.net/npm/@signumjs/core/dist/signumjs.min.js'></script>
<script src='https://cdn.jsdelivr.net/npm/@signumjs/util/dist/signumjs.util.min.js'></script>
*/

// Create the Api instance to connect to a blockchain node
const api = sig$.composeApi({
    nodeHost: "https://europe.signum.network"
});

// here we check for a certain attachment type, and get the text message if not encrypted
const getMessageText = transaction =>
    sig$.isAttachmentVersion(transaction, 'EncryptedMessage')
        ? '<encrypted>'
        : transaction.attachment.message;

async function listMessages(account) {
    try {
        const accountId = sig$.Address.create(account).getNumericId()

        // here we can explicitly filter by Transaction Types
        const {transactions} = await api.account.getAccountTransactions(
            {
                accountId,
                lastIndex: 20, // getting only the most recent 20
                type: sig$.TransactionType.Arbitrary,
                subtype: sig$.TransactionArbitrarySubtype.Message
            }
        );

        // now we iterate through the transactions and print in a formatted way
        transactions.forEach(t => {
            console.info(`On ${sig$util.ChainTime.fromChainTimestamp(t.blockTimestamp).getDate()}`)
            console.info(`From ${t.senderRS}`)
            console.info(`To ${t.recipientRS}`)
            console.info('Message:\n', getMessageText(t), '\n---')
        })

    } catch (e) {
        console.error(e)
    }
}
🧾
Modules
here
composeApi
api.account.getAccountTransactions
isAttachmentVersion
TransactionType
Address
ChainTime