PSP37 Metadata

This example shows how you can reuse the implementation of PSP37 token with PSP37Metadata extension.

First, you should implement basic version of PSP37.

Step 1: Implement PSP37Metadata

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

#[openbrush::implementation(PSP37, PSP37Metadata)]
#[openbrush::contract]
pub mod my_psp37 {
...

Step 2: Define storage

Declare storage struct and declare the field related to the metadata module. 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 PSP37Metadata extension in your PSP37 implementation.

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

Step 3: Define constructor

Define constructor. Your PSP37Metadata contract is ready!

impl Contract {
    #[ink(constructor)]
    pub fn new() -> Self {
        Self::default()
    }
}

Final code

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

#[openbrush::implementation(PSP37, PSP37Metadata)]
#[openbrush::contract]
pub mod my_psp37 {
    use openbrush::traits::{
        Storage,
        String,
    };

    #[derive(Default, Storage)]
    #[ink(storage)]
    pub struct Contract {
        #[storage_field]
        psp37: psp37::Data,
        #[storage_field]
        metadata: metadata::Data,
    }

    impl Contract {
        #[ink(constructor)]
        pub fn new() -> Self {
            Self::default()
        }

        #[ink(message)]
        pub fn set_attribute(&mut self, id: Id, key: String, data: String) -> Result<(), PSP37Error> {
            metadata::Internal::_set_attribute(self, &id, &key, &data)
        }
    }
}

You can check an example of the usage of PSP37 Metadata.