🖨️Internals

The PaymentUtils class provides several utility functions for handling USDT transfers, placing buy orders for UBIT, and interacting with the UBIT testnet and mainnet. Here is a detailed explanation of each function within the class:

1. mainnetUSCTransfer

This function coordinates a series of actions to transfer USDT, place a UBIT buy order, and withdraw funds to a user.

Steps:

1. Get Deposit Address:

   • Calls getDepositAddress to get a deposit address for the specified amount and address.

   • If the address is null, it throws an exception.

2. Transfer USDT:

   • Calls USDTTransfer to transfer the specified amount of USDT to the retrieved deposit address.

3. Place UBIT Buy Order:

   • Calls placeUBITBuyOrder to place a buy order for UBIT with the specified amount.

4. Withdraw to User:

   • Calls withdrawToUser to withdraw the specified amount to the user's address.

2. USDTTransfer

This function handles the transfer of USDT from one address to another using the Ethereum blockchain.

Steps:

1. Set Up Provider and Wallet:

   • Retrieves the private key and RPC URL from environment variables.

   • Creates a provider and a wallet using the ethers library.

2. Define Transfer ABI:

   • Defines the ABI for the transfer function of the USDT contract.

3. Create Contract Instance:

   • Creates an instance of the USDT contract using the ABI and the provider's signer.

4. Transfer Tokens:

   • Calls the transfer function of the USDT contract to transfer the specified amount of USDT (converted to the appropriate token decimals) to the specified address.

   • Logs the transfer result or error.

3. withdrawToUser

This function withdraws funds to a user's address using a specific API.

Steps:

1. Prepare Payload and Headers:

   • Creates a payload with the withdrawal details.

   • Creates a signature for the payload using HMAC-SHA256 with a secret key.

   • Sets up headers with the API key, signature, expiration time, and other necessary headers.

2. Make API Call:

   • Sends a POST request to the withdrawal API with the payload and headers.

   • Logs the response data or error.

4. getDepositAddress

This function retrieves a deposit address for the specified amount and address.

Steps:

1. Prepare Payload and Headers:

   • Creates a payload with the deposit details.

   • Creates a signature for the payload using HMAC-SHA256 with a secret key.

   • Sets up headers with the API key, signature, expiration time, and other necessary headers.

2. Make API Call:

   • Sends a POST request to the deposit address API with the payload and headers.

   • Sets the addr variable to the retrieved address from the response data.

   • Logs any errors.

3. Return Address:

   • Returns the retrieved deposit address.

5. placeUBITBuyOrder

This function places a buy order for UBIT using a specific API.

Steps:

1. Prepare Payload and Headers:

   • Creates a payload with the buy order details.

   • Creates a signature for the payload using HMAC-SHA256 with a secret key.

   • Sets up headers with the API key, signature, expiration time, and other necessary headers.

2. Make API Call:

   • Sends a POST request to the order placement API with the payload and headers.

   • Logs the response data or error.

6. testnetUSCTransfer

This function handles the transfer of USC on the UBIT testnet.

Steps:

1. Set Up Provider and Wallet:

   • Retrieves the private key and RPC URL from environment variables.

   • Creates a provider and a wallet using the ethers library.

2. Create Transaction:

   • Creates a transaction object with the specified address, amount (converted to the appropriate token decimals), and gas limit.

3. Send Transaction:

   • Sends the transaction using the wallet.

   • Waits for the transaction to be mined and logs the receipt.

   • Returns the transaction hash.

Error Handling

• The HttpException class is used to handle errors and provide appropriate status codes and messages.

• Errors are logged and rethrown where necessary to ensure proper error handling and feedback.

Environment Variables

• ESCROW_PRIV_KEY: Private key for the wallet used in transfers.

• UBIT_TESTNET_RPC: RPC URL for the UBIT testnet.

• WITHDRAW_API: API endpoint for withdrawals.

• COINSTORE_API_KEY: API key for the Coinstore platform.

• COINSTORE_SECRET_KEY: Secret key for the Coinstore platform.

• DEPOSIT_ADDR: API endpoint for getting deposit addresses.

• ORDER_PLACE: API endpoint for placing orders.