Encoding of multiple Values

In this section, we will learn how to pack multiple values into a single message.

We can use abi.encode() to encode multiple values into a single byte array:

bytes message = abi.encode(
      someString,
      someNumber,
      someAddress
  );

We can see here in how we use the function abi.encode() to turn multiple values (someString, someNumber & someAddress) of various types (string, uint & address) into a single value of the type bytes called message. This bytearray can then be sent to the destination chain using the Teleporter.

function sendMessage(address destinationAddress) external returns (uint256 messageID) {
  string someString = "test";
  uint someNumber = 43;
  address someAddress = address(0);
 
  bytes message = abi.encode( 
      someString,
      someNumber,
      someAddress
  );
 
  return teleporterMessenger.sendCrossChainMessage(
      TeleporterMessageInput({
        destinationChainID: destinationChainID,
        destinationAddress: destinationAddress,
        feeInfo: TeleporterFeeInfo({
          feeTokenAddress: feeContractAddress,
          amount: adjustedFeeAmount
        }),
        requiredGasLimit: requiredGasLimit,
        allowedRelayerAddresses: new address[](0),
        message: message 
      })
  );
}

The receiving contract can then decode the byte array back into its original values:

function receiveTeleporterMessage(
  bytes32 originChainID,
  address originSenderAddress,
  bytes calldata message
) external {
  // Only the Teleporter receiver can deliver a message.
  if (msg.sender != address(teleporterMessenger)) {
    revert Unauthorized();
  }
 
  // Decoding the function parameters
  (
    string someString,
    uint256 someNumber,
    address someAddress
  ) = abi.decode(message, (string, uint256, address));
  
  // Calling the internal function
  _someFunction(someString, someNumber, someAddress) 
  
}
 
function _someFunction(string someString, uint256 someNumber, address someAddress) private {
  // Do something
}

Here we are using abi.decode() to unpack the three values (someString, someNumber & someAddress) from the parameter message of the type bytes. As you can see in we do need to provide the message as well as the types of the values encoded in the message in the same order as parameters to abi.decode().

(
  string memory someString,
  uint someNumber,
  address someAddress
) = abi.decode(message, (string, uint, address));

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