Aptos Module

🚀 Your First Aptos Module on M1 using Movement CLI

Requirements

Ensure you have the Aptos CLI installed.

Initialize Your Environment

1. Initialize your Aptos profile for package development and add Movement as a custom network:

   aptos init --network custom --rest-url https://aptos.testnet.suzuka.movementlabs.xyz/v1

2. Initialize your Move project:

   aptos move init --name hello_blockchain

If you generated your project using the movementdev/movement-hack template, your project should have the following structure:

.gitignore
/.movement
    config.yaml
/ sources
    hello_blockchain.move
    hello_blockchain_test.move
Move.toml

The hello_blockchain.move file contains a simple module for setting the value of a message resource. If you don’t have this file, you can create it by copying the following code into a new file inside the sources directory called hello_blockchain.move.

module hello_blockchain::message {
    use std::error;
    use std::signer;
    use std::string::{utf8, String};
    use aptos_framework::account;
    use aptos_framework::event;

    struct MessageHolder has key {
        message: String,
        message_change_events: event::EventHandle<MessageChangeEvent>,
    }

    struct MessageChangeEvent has drop, store {
        from_message: String,
        to_message: String,
    }

    /// Error code indicating no message is present
    const ENO_MESSAGE: u64 = 0;

    #[view]
    public fun signature(): address {
        @<address>
    }

    #[view]
    public fun get_message(addr: address): String acquires MessageHolder {
        assert!(exists<MessageHolder>(addr), error::not_found(ENO_MESSAGE));
        borrow_global<MessageHolder>(addr).message
    }

    public entry fun set_message(account: signer, message: String) acquires MessageHolder {
        let account_addr = signer::address_of(&account);
        if (!exists<MessageHolder>(account_addr)) {
            move_to(&account, MessageHolder {
                message,
                message_change_events: account::new_event_handle<MessageChangeEvent>(&account),
            });
        } else {
            let old_message_holder = borrow_global_mut<MessageHolder>(account_addr);
            let from_message = old_message_holder.message;
            event::emit_event(&mut old_message_holder.message_change_events, MessageChangeEvent {
                from_message,
                to_message: copy message,
            });
            old_message_holder.message = message;
        }
    }

    #[test(account = @0x1)]
    public entry fun sender_can_set_message(account: signer) acquires MessageHolder {
        let addr = signer::address_of(&account);
        aptos_framework::account::create_account_for_test(addr);
        set_message(account, utf8(b"Hello, Blockchain"));

        assert!(get_message(addr) == utf8(b"Hello, Blockchain"), ENO_MESSAGE);
    }

    #[test]
    public fun signature_okay() {
        assert!(signature() == @<address>, ENO_MESSAGE);
    }
}



You will also need to add the following to `Move.toml`.
```toml
[package]
name = "hello_blockchain"
version = "0.0.1"

[dependencies]
AptosFramework = { git = "https://github.com/aptos-labs/aptos-core.git", subdir = "aptos-move/framework/aptos-framework", rev = "main" }

[addresses]
std = "0x1"

Now you need to setup your config.yaml file. This will setup a private key for your environment. Choose testnet during setup!

aptos init

Run the tests with the aptos CLI

aptos move test --named-addresses hello_blockchain=default

If your test has passed, you can now publish your module to the testnet.

aptos move publish --named-addresses hello_blockchain=default

Make sure to accept the transaction in the prompt. You can now check the status of your transaction using the Movement CLI.

Afterwards, you can run the module on the testnet. You are going to set the message to "hello!".

aptos move run --function-id default::message::set_message --args string:hello!

Make sure to check the resources of the account you used to publish the module. You should see a MessageHolder resource.

aptos account list --query resources --account default

You can now check the message of the account.

aptos move run --function-id default::message::get_message --args address:default

Congratulations! You have just written, published, and executed your first Move module on the testnet!