Show attached messages

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

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:

pageModules

A fully working example is available here

Following functions from SignumJS are used in this example

• composeApi function to create the api instance

• api.account.getAccountTransactions function to fetch the transactions from the blockchain

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

• TransactionType enums to filter for the specific message types

• Address Value Object to parse and convert the given address

• ChainTime Value Object to convert between blockchain timestamp and real date

Javascript

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)
    }
}

Typescript

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)
    }
}

<script/>

// 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)
    }
}