Stellar Smart SDK

Overview

To demonstrate the Stellar Smart SDK, take a look at the Stellar Blogger, and the Stellar Data SDK.

The Stellar Smart SDK lets you send 638 text characters in one Stellar transaction, for just .001 XLM (about $0.00025). You can use this capability to create Shopping Carts, Tweets, and Discussion Forums on the Stellar blockchain.

Previously, the Memo field was the only way to include text with your payment. The Memo field only allows 32 characters per transaction, so it would take 20 transactions to send 638 characters. It takes 6 seconds to send each transaction to the Stellar blockchain, so it would take 120 seconds to do what the Stellar Smart SDK does in just 6 seconds. This SDK uses micro-payments to send text (this is described below).

Use on Test Network or Main Network

This SDK lets you use the Test Network, which is free to use. However, the Test Network can be ten times slower than the Main Network, because it often requires multiple retries to send a transaction. When using the Main Network. I have not encountered any retries.

This SDK allows up to 20 retries for a transaction to be sent. On the Test Network, the most retries I encountered was 6, which took about 60 seconds to send one transaction.

The transaction fee to send text on the Main Network is only $0.0000004 per character, so you can send 32k of text (100 Blog Entries with 320 characters in each) for a total fee of just 1 cent.

Message Sender Account

The Message Sender Account must contain at least 1.51 XLM, which is the 1.5 XLM minimum balance, plus .01 XLM as the transaction fee to send messages.

There are two ways to select a Stellar account that messages will be sent from:

1. Private Key: This SDK includes a property named sSenderAddress_Secret, which your code must set if the Rabet Chrome Extension is not used. This is described below.
2. Rabet Chrome Extension: This Chrome Extension lets you select a Stellar Account without disclosing your Private Key. When you call the SDK's SendMessage function, you will be prompted to sign the transaction on the Rabet popup.

SDK Constructor

constructor(sReceiverAddress, sAssetCode, bIsTestnet):

Call this function to create a Smart SDK object.
For example: var gobjSDK = await new StellarSmartSDK2('GDEWWXY4Q5454HYN6FLLV3G44EAX7AB5HIPFTUMBOW', "MyToken", true)

The constructor requires the following three parameters:

1. sReceiverAddress: Any Stellar account with at least 1 XLM can be used as a Message Receiver Account.
2. sAssetCode:: The Asset Code is a string with no more than 12 alphabetical characters, which indicates the Token that will be used to create the Micro-payments. Each Message Receiver Account may store multiple "databases", as messages will only be read and written for the selected Asset Code.
3. bIsTestnet: If set to true, the Test Network will be used. If set to false, the Main Network will be used.

GetMessages() function

When the constructor is called, the SDK calls its GetMessages() function, which retrieves all the Payments from the selected Stellar account.

The GetMessages() function then parses the Payment data into Messages, which are placed into an object array named objMessages which contains the following fields:

• from: The Stellar address that sent the message.
• message: The message that was sent.
• timestamp: The numeric epoch timestamp.

Therefore, by just creating a Smart SDK object named gobjSDK, you will have an object named gobjSDK.objMessages which contains all the messages that had been sent to the selected Stellar address.

sSender_PrivateKey property

If the Rabet Chrome Extension is not being used, then you must set this property with the Private Key of the Message Sender Account, before sending a message.
For example: gobjSDK.objMessages.sSender_PrivateKey = 'SBKRL3MNTPWIOUIBTN55FDOD3JGYTR99QHIQDRFBIJY'

SendMessage(sMessage) function:

For example: gobjSDK.SendMessage("This is a test")

This function will send a message from the selected Message Sender Account, to the Message Receiver Account that was set in the constructor. If the Rabet Chrome Extension is being used, then the SDK will prompt the user to sign the transaction on the Rabet popup. If the Rabet Chrome Extension is not being used, then the SDK will use the sSender_PrivateKey property to sign the transaction.

A Message may contain up to 638 characters. The Stellar Blogger website adds several JSON characters to each message, so the maximum length for a Blog Entry or Blog Comment is 618 characters.

Micro-payments as Text

The Stellar Smart SDK uses Micro-payments to send up to 638 text characters in each transaction.

Each Stellar transaction may contain up to 100 Operations, and each Operation may contain a Payment. This SDK combines 16 digits from each Payment Amount, to create a Long Number that can represent text.

For example, the string "abc" can be converted to the following bytes32/hex: 0x616263
(You can confirm this at https://web3-type-converter.onbrn.com)

The Hex string 0x616263 can be converted to this Long Number: 6382179
(You can confirm this at https://www.rapidtables.com/convert/number/hex-to-decimal.html)

Therefore, the string "abc" can be stored on the Stellar network as this Payment Amount:

• .6382179

This SDK does not use the Memo field to store additional text, because it is five times slower to retrieve records from the Horizon API when "&join=transactions" is added to the URL that retrieves Operations.