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Near Drop

A near-drop is a smart contract that allows users to create NEAR/FT/NFT drop and claim created drops by another user using a PublicKey.

Particularly, it shows:

  1. How to calculate storage costs
  2. How to create a NEAR drop.
  3. How to create a FT drop.
  4. How to create a NFT drop.
  5. How to claim a drop for an existing account.
  6. How to claim a drop for a new account.

Contract State​

  • top_level_account - that account is used to create new accounts. It has to have create_account method.
  • next_drop_id - that id will be assigned to the next created drop.
  • drop_id_by_key - that LookupMap structure contains relations between PublicKey and DropId. PublicKey is used to claim drop. DropId is a unique identificator by which you can get drop's data like amount of tokens to drop, FT or NFT contract, etc.
  • drop_by_id - that LookupMap structure contains relations between DropId and actual drop data - Drop.

Drop Types​

There are 3 types of drops, which differ in what the user will receive when he claims the corresponding drop - NEAR, fungible tokens (FTs) or non-fungible tokens (NFTs).

Create a drop​

Creating drop functions looks very similar, the main difference is in the structures used to store the drop data.

Claim a drop​

In order to claim drop claiming methods have to be called by near-drop contract and signed with a corresponding PublicKey. There are two ways to claim a drop: claim for an existing account and claim for a new account. In last case claimer account will be created.

When a drop is claimed, its counter decreases by 1 and corresponding relation between PublicKey and DropId removing from the contract state (drop_id_by_key collection).

When all drops are claimed (counter == 0), relation between DropId and Drop removing from the drop_by_id collection as well.

Claim for an existing account​

Claim for a new account​

Testing the Contract​

The contract readily includes a sandbox testing to validate its functionality. To execute the tests, run the following command:

cargo test
tip

The integration tests use a sandbox to create NEAR users and simulate interactions with the contract.

Deploying the Contract to the NEAR network​

In order to deploy the contract you will need to create a NEAR account.

# Create a new account pre-funded by a faucet
near create-account <accountId> --useFaucet

Then build and deploy the contract:

cargo near build

cargo near deploy <accountId> with-init-call new json-args '{"top_level_account": "testnet"}' prepaid-gas '100.0 Tgas' attached-deposit '0 NEAR' network-config testnet sign-with-keychain send

CLI: Interacting with the Contract​

To interact with the contract through the console, you can use the following commands:

# create a NEAR drop
near call <account-id> create_near_drop '{"public_keys": ["ed25519:AvBVZDQrg8pCpEDFUpgeLYLRGUW8s5h57NGhb1Tc4H5q", "ed25519:4FMNvbvU4epP3HL9mRRefsJ2tMECvNLfAYDa9h8eUEa4"], "amount_per_drop": "10000000000000000000000"}' --accountId <account-id> --deposit 1 --gas 100000000000000

# create a FT drop
near call <account-id> create_ft_drop '{"public_keys": ["ed25519:HcwvxZXSCX341Pe4vo9FLTzoRab9N8MWGZ2isxZjk1b8", "ed25519:5oN7Yk7FKQMKpuP4aroWgNoFfVDLnY3zmRnqYk9fuEvR"], "amount_per_drop": "1", "ft_contract": "<ft-contract-account-id>"}' --accountId <account-id> --gas 100000000000000

# create a NFT drop
near call <account-id> create_nft_drop '{"public_key": "ed25519:HcwvxZXSCX341Pe4vo9FLTzoRab9N8MWGZ2isxZjk1b8", "nft_contract": "<nft-contract-account-id>"}' --accountId <account-id> --gas 100000000000000

# claim to an existing account
# see the full version

# claim to a new account
# see the full version
Versioning for this article

At the time of this writing, this example works with the following versions:

  • near-cli: 0.17.0
  • rustc: 1.82.0
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