PSP34 Metadata

This example shows how you can reuse the implementation of PSP34 token with PSP34Metadata extension.

First, you should implement basic version of PSP34.

Step 1: Implement features

#![cfg_attr(not(feature = "std"), no_std, no_main)]

#[openbrush::implementation(PSP34, PSP34Metadata)]
#[openbrush::contract]
pub mod my_psp34_metadata {
...

Step 2: Define storage

Declare storage struct and declare the field related to the metadata module data structure. Then you need to derive the Storage trait and mark the corresponding field with the #[storage_field] attribute. Deriving this trait allows you to reuse the PSP34Metadata extension in your PSP34 implementation.

#[derive(Default, Storage)]
#[ink(storage)]
pub struct Contract {
    #[storage_field]
    psp34: psp34::Data,
    #[storage_field]
    metadata: metadata::Data,
}

Step 3: Define constructor

Define constructor. Your PSP34Metadata contract is ready!

impl Contract {
    /// A constructor which mints the first token to the owner
    #[ink(constructor)]
    pub fn new(id: Id, name: String, symbol: String) -> Self {
        let mut instance = Self::default();

        let name_key = String::from("name");
        let symbol_key = String::from("symbol");
        metadata::Internal::_set_attribute(&mut instance, id.clone(), name_key, name);
        metadata::Internal::_set_attribute(&mut instance, id, symbol_key, symbol);

        instance
    }
}

Final code

#![cfg_attr(not(feature = "std"), no_std, no_main)]

#[openbrush::implementation(PSP34, PSP34Metadata)]
#[openbrush::contract]
pub mod my_psp34_metadata {
    use openbrush::traits::Storage;

    #[derive(Default, Storage)]
    #[ink(storage)]
    pub struct Contract {
        #[storage_field]
        psp34: psp34::Data,
        #[storage_field]
        metadata: metadata::Data,
    }

    impl Contract {
        /// A constructor which mints the first token to the owner
        #[ink(constructor)]
        pub fn new(id: Id, name: String, symbol: String) -> Self {
            let mut instance = Self::default();

            let name_key = String::from("name");
            let symbol_key = String::from("symbol");
            metadata::Internal::_set_attribute(&mut instance, id.clone(), name_key, name);
            metadata::Internal::_set_attribute(&mut instance, id, symbol_key, symbol);

            instance
        }
    }
}

You can check an example of the usage of PSP34 Metadata.