Donation Contract

The smart contract exposes multiple methods to handle donating money to a beneficiary set on initialization.

How to Build Locally?

Install cargo-near and run:

cargo near build

How to Test Locally?

cargo test

How to Interact?

In this example we will be using NEAR CLI to intract with the NEAR blockchain and the smart contract

If you want full control over of your interactions we recommend using the near-cli-rs.

Initialize

The contract will be automatically initialized with a default beneficiary. To initialize the contract yourself do:

near call <deployed-to-account> init '{"beneficiary":"<account>"}' --accountId <deployed-to-account>

Get Beneficiary

get_beneficiary is a read-only method (view method) that returns the beneficiary of the donations.

View methods can be called for free by anyone, even people without a NEAR account!

near view <deployed-to-account> get_beneficiary

Change Beneficiary

change_beneficiary is a read-only method (view method) that returns the beneficiary of the donations.

View methods can be called for free by anyone, even people without a NEAR account!

near call <deployed-to-account> change_beneficiary {"new_beneficiary": "<new-baccount>"} --accountId <deployed-to-account>

Donate

donate forwards any attached NEAR tokens to the beneficiary while keeping track of it.

donate is a payable method for which can only be invoked using a NEAR account. The account needs to attach NEAR Tokens and pay GAS for the transaction.

near call <deployed-to-account> donate --amount 1 --accountId <account>

#[payable]
    pub fn donate(&mut self) -> String {
        // Get who is calling the method and how much NEAR they attached
        let donor: AccountId = env::predecessor_account_id();
        let donation_amount = env::attached_deposit();

        require!(
            donation_amount > STORAGE_COST,
            format!(
                "Attach at least {} yoctoNEAR to cover for the storage cost",
                STORAGE_COST
            )
        );

        let mut donated_so_far: NearToken = self
            .donations
            .get(&donor)
            .unwrap_or(NearToken::from_near(0));

        let to_transfer = if donated_so_far.is_zero() {
            // This is the user's first donation, lets register it, which increases storage
            // Subtract the storage cost to the amount to transfer
            donation_amount.saturating_sub(STORAGE_COST).to_owned()
        } else {
            donation_amount
        };

        // Persist in storage the amount donated so far
        donated_so_far = donated_so_far.saturating_add(donation_amount);

        self.donations.insert(&donor, &donated_so_far);

        log!(
            "Thank you {} for donating {}! You donated a total of {}",
            donor.clone(),
            donation_amount,
            donated_so_far
        );

        // Send the NEAR to the beneficiary
        Promise::new(self.beneficiary.clone()).transfer(to_transfer);

        // Return the total amount donated so far
        donated_so_far.to_string()
    }

Get Number of Donors

near view <deployed-to-account> number_of_donors

Get Donations for Account

near view <deployed-to-account> get_donation_for_account '{"account_id":"<account>"}'

Get Total Donations

near view <deployed-to-account> get_donations

Useful Links

• cargo-near - NEAR smart contract development toolkit for Rust
• near CLI-RS - Iteract with NEAR blockchain from command line
• NEAR Rust SDK Documentation
• NEAR Documentation
• NEAR StackOverflow
• NEAR Discord
• NEAR Telegram Developers Community Group
• NEAR DevHub: Telegram, Twitter