Building a CrossChain Decentralized Application with LayerZero

What is LayerZero?

LayerZero offers omnichannel communication, interoperability, and decentralized infrastructure. It is a fully integrated system designed to send deep messages across blockchains. LayerZero provides accurate and reliable delivery.

Concepts:

1. Message State

A message is sent from the source srcUA's user application (UA) to the target dstUA's UA. When dstUA receives the message, it is decided to send the message (during the transition to processing or storage).

code:

// message handling at destination chain
try ILayerZeroReceiver(_dstAddress).lzReceive{gas: _gasLimit}(_srcChainId, _srcAddress, _nonce, _payload) {
// message state becomes SUCCESS
} catch {
// message state becomes STORED
emit PayloadStored(_srcChainId, _srcAddress, _dstAddress, _payload);
}

2. LayerZero Endpoint:

Messages in LayerZero are sent and received by LayerZero, which manages sending, analyzing and receiving messages; This endpoint consists of two things: a collection of versioned libraries and a routing message for the right book. library version. When the message reaches the endpoint, the endpoint chooses the library version configured by the User Application to process the message. Endpoints store all status messages across models, allowing for easy replacement of libraries for maintenance or optimization.

3. Future-proof Architecture:

a. Immutable Endpoints:

The LayerZero endpoint is the only interface for the User Application (UA). This tip allows the user of the application to configure the mail library used to send and receive certificates and to guarantee the order in which messages are sent across all mail libraries.
Send(): The message will be sent to the endpoint first and then sent back to the UA configured messaging library
Accept(): The message will be acknowledged in the library mail first, then sent to the end and finally sent to the UA

b. Perpetual Messaging:

Once deployed, all stores will be put into permanent use; this means that no site (such as LayerZero Lab multi-signature) can exit a store or change the UA message store configuration; No organization can block the message flow if it has set up the message store using the message store.

c. Continuous Improvement:

LayerZero can use new libraries for security and performance (eg. better evidence systems). This allows LayerZero to bring the best research results into production and support the system with the best technology. The UA interface will not change, UA can easily and easily switch to a new one. For each messaging library (eg. ultralight nodes), LayerZero may send new authentication information for security or performance reasons.

d. Immutable UA Configuration:

If the UA has specified an authentication library to use, no entity can change the configuration.

Getting started with LayerZero:

Step-1: clone this repo:
https://github.com/LayerZero-Labs/solidity-examples.git

Step-2: Install all the dependencies and configure hardhat.config.js file

Step-3: Follow the instructions given for OmniCounter.sol:

OmniCounter.sol: It is a simple contract with a counter. You can only remotely increment the counter!

Deploy both OmniCounters:

npx hardhat --network bsc-testnet deploy --tags OmniCounter
npx hardhat --network fuji deploy --tags OmniCounter

Set the remote addresses, so each contract can receive messages

npx hardhat --network bsc-testnet setTrustedRemote --target-network fuji --contract OmniCounter
npx hardhat --network fuji setTrustedRemote --target-network bsc-testnet --contract OmniCounter