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Linkdrops

Linkdrops allow users to distribute assets and onboard people to Web3 apps through a simple web link.

Linkdrop

They work by storing assets and linking AccessKeys to them. The AccessKeys are then distributed to users in the form of web links. These links take users to a website that automatically uses the keys to call the claim method in the linkdrop contract.

In order for a contract to be considered a Linkdrop-contract it has to follow the NEP-452 standard. The NEP-452 explains the minimum interface required to be implemented, as well as the expected functionality.

Keypom​

The simplest way to create Linkdrops is by using Keypom. Keypom is a community project that allows you to create Linkdrops for NEAR tokens and NFTs in a few clicks.

keypom

AccessKeys​

In order to create any kind of drop, you need to first generate key pairs. You will need to create one key per drop.

  • The linkdrop contract will store the public part of the key.
  • You will give the private part of the key to the user you want to receive the drop.
import { KeyPair } from 'near-api-js';

const newKeyPair = KeyPair.fromRandom('ed25519');
newKeyPair.public_key = newKeyPair.publicKey.toString();

$NEAR Drops​

To create a $NEAR drop you will ask the contract to create a drop (create_drop), passing the public part of the keys you generated, and how much you want to drop on each key use (deposit_per_use).

The contract will create a drop and return the numerical ID that identifies it.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const DROP_AMOUNT = "10000000000000000000000"; // 0.1 NEAR

const wallet = new Wallet({ createAccessKeyFor: KEYPOM_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "create_drop",
  contractId: KEYPOM_CONTRACT_ADDRESS,
  args: {
    public_keys: state.publicKeys,
    deposit_per_use: DROP_AMOUNT,
  },
  deposit: "23000000000000000000000" // state.publicKeys.length * dropAmount + 3000000000000000000000,
  gas: "100000000000000",
});

The Wallet object comes from our quickstart template

info

To claim the drop, you will need to send the user a link with the private key

NFT Drops​

To drop an existing NFT, you will (1) create a drop, and then (2) transfer the NFT to keypom.

1. Creating the Drop​

To create an NFT drop, you will call the create_drop method, now passing a nft argument, which will tell the linkdrop contract to wait for an NFT to be transferred.

The contract will then create a drop and return the numerical ID that identifies it.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const NFT_CONTRACT_ADDRESS = "nft.primitives.near";
const DROP_AMOUNT = "10000000000000000000000";

const keypomConnectedWallet = new Wallet({ createAccessKeyFor: KEYPOM_CONTRACT_ADDRESS });
const nftConnectedWallet = new Wallet({ createAccessKeyFor: NFT_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "create_drop",
  contractId: KEYPOM_CONTRACT_ADDRESS,
  args: {
    public_keys: state.publicKeys,
    deposit_per_use: DROP_AMOUNT,
    nft: {
      // Who will be sending the NFTs to the Keypom contract
      sender_id: accountId, // TODO How to get it
      // NFT Contract Id that the tokens will come from
      contract_id: NFT_CONTRACT_ADDRESS,
    },
  },
  deposit: "23000000000000000000000" // state.publicKeys.length * dropAmount + 3000000000000000000000,
  gas: "100000000000000",
});

The Wallet object comes from our quickstart template

2. Transferring the NFT​

Having the Drop ID, you now need to transfer the NFT to the linkdrop contract, specifying to which drop you want to add it.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const NFT_CONTRACT_ADDRESS = "nft.primitives.near";
const NFT_TOKEN_ID = "1";
const DROP_AMOUNT = "10000000000000000000000";

const nftConnectedWallet = new Wallet({ createAccessKeyFor: NFT_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "nft_transfer_call",
  contractId: NFT_CONTRACT_ADDRESS,
  args: {
    receiver_id: keypomContract,
    token_id: nftTokenId,
    msg: dropId.toString()
  },
  deposit: 1,
  gas: "100000000000000",
});

The Wallet object comes from our quickstart template

tip

The linkdrop contract will validate that you are transferring the NFT to a drop that belongs to you

FT Drops​

The process to drop a Fungible Token is very similar to that of creating an NFT drop. You will first create the drop, and then fund it with FTs.

1.Creating a drop​

To create a FT drop you will call the create_drop method, now passing a ftData argument, which will tell the linkdrop contract to wait for a certain amount of FT to be transferred.

The contract will then create a drop and return the numerical ID that identifies it.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const FT_CONTRACT_ADDRESS = "ft.primitives.near";
const DROP_AMOUNT = "10000000000000000000000";

const wallet = new Wallet({ createAccessKeyFor: KEYPOM_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "create_drop",
  contractId: KEYPOM_CONTRACT_ADDRESS,
  args: {
    public_keys: state.publicKeys,
    deposit_per_use: DROP_AMOUNT,
    ftData: {
      contractId: FT_CONTRACT_ADDRESS,
      senderId: accountId, // TODO How to get account id
      // This balance per use is balance of human readable FTs per use.
      amount: "1"
      // Alternatively, you could use absoluteAmount, which is dependant on the decimals value of the FT
      // ex. if decimals of an ft = 8, then 1 FT token would be absoluteAmount = 100000000
    },
  },
  deposit: "23000000000000000000000" // state.publicKeys.length * dropAmount + 3000000000000000000000,
  gas: "100000000000000",
});

The Wallet object comes from our quickstart template

2. Transferring FT​

Having the Drop ID, you now need to transfer the fungible tokens to the linkdrop contract.

note

To transfer FTs to an account, you need to first register the receiver account (e.g. the keypom contract) on the FT contract.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const FT_CONTRACT_ADDRESS = "ft.primitives.near";

const wallet = new Wallet({ createAccessKeyFor: FT_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "ft_transfer",
  contractId: FT_CONTRACT_ADDRESS,
  args: {
    receiver_id: KEYPOM_CONTRACT_ADDRESS,
    amount: "1"
  },
  deposit: "1",
  gas: "100000000000000"
});

The Wallet object comes from our quickstart template

Function Call Drop​

Linkdrop contracts allow to create function call drops. These drops will execute one or more methods on a contract when the user claims the drop.

tip

Function call drops can be thought as the abstract version of other drops: you can create a drop that will mint an NFT, register a user in a DAO, or pay for a service.

import { Wallet } from './near-wallet';

const KEYPOM_CONTRACT_ADDRESS = "v2.keypom.near";
const NFT_CONTRACT_ADDRESS = "nft.primitives.near";
const NFT_TOKEN_ID = "1";
const DROP_AMOUNT = "10000000000000000000000";

const wallet = new Wallet({ createAccessKeyFor: DAO_CONTRACT_ADDRESS });

await wallet.callMethod({
  method: "create_drop",
  contractId: KEYPOM_CONTRACT_ADDRESS,
  args: {
    public_keys: state.publicKeys,
    deposit_per_use: DROP_AMOUNT,
    fcData: {
      // 2D array of function calls. In this case, there is 1 function call to make for a key use
      // By default, if only one array of methods is present, this array of function calls will be used for all key uses
      methods: [
        // Array of functions for Key use 1.
          [{
            receiverId: NFT_CONTRACT_ADDRESS,
            methodName: "nft_mint",
            args: JSON.stringify({
            // Change this token_id if it already exists -> check explorer transaction
                token_id: NFT_TOKEN_ID,
                metadata: {
                  title: "My NFT drop",
                  description: "",
                  media: "",
                }
            }),
            accountIdField: "receiver_id",
            // Attached deposit for when the receiver makes this function call
            attachedDeposit: "10000000000000000000000"
          }]
      ]
    }
  },
  deposit: "23000000000000000000000" // state.publicKeys.length * dropAmount + 3000000000000000000000,
  gas: "100000000000000",
});

The Wallet object comes from our quickstart template

const getLinks = () => {
  const links = [];

  // It assumes that private keys have been already stored in State by using State.init() and State.update() method
  state.privKeys.map((e, i) => {
    const link =
      "https://app.mynearwallet.com" + "/linkdrop/v2.keypom.near/" + e;
    links.push(link);
  });

  return links;
};
Example response

[
  'https://app.mynearwallet.com/linkdrop/v2.keypom.near/ed25519:2H32THYM8ob336yk81cZUxpidvKi34zLck6a97ypmCY8bbSAuEfrCTu9LWmWGiG9df2C6vkg2FGKGZzY9qE4aEcj',
  'https://app.mynearwallet.com/linkdrop/v2.keypom.near/ed25519:3eoMcqKmmY9Q6qgBy3hZy65HisZ8NXQd9aGGYUGe6RRsmNpGJS5YN64MgZaBVVYJJhbFXhQ2ca3DRRBiKh1rYM48'
]

note

If you didn't save your linkdrop links before closing NEAR App, you can always find them on Keypom app.

Additional Resources​

  1. Linkdrop plus allows to create a Simple Drop. Powered by Keypom
  2. Keypom Drop Viewer shows drops created by current logged in user.
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