docs/_develop/connect/use-with-clarity.md

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Signing transactions

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With Connect, you can interact with the Stacks 2.0 blockchain. You can allow your users to send transactions and interact with smart contracts.

Transaction signing is still in progress

To use these features, make sure you install the testnet tag the @blockstack/connect NPM package. You can do this by running npm install --save @blockstack/connect@testnet, or by specifying testnet as the version in your package.json file.

The Stacks 2.0 blockchain is still in testnet, and our web app integration is also still in beta. In order to use transaction signing in your application, you need to use the configuration `authOrigin` with `@blockstack/connect`.

  
    const options = {
      // your other options
      authOrigin: 'https://deploy-preview-301--stacks-authenticator.netlify.app'
    };
  

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How it works

For your app's users to be able to execute a smart contract function, they need to sign and broadcast a transaction. It's important that users remain in control of the private keys that sign these transactions. Connect provides an easy-to-use workflow that allows your users to securely sign transactions.

Connect allows you to open the authenticator with parameters indicating the details of the transaction - like the smart contract address, function name, and specific arguments. Your users get the chance to see these details, and then sign and broadcast the transaction in a single click. Their transaction will be securely signed and broadcasted onto the Stacks blockchain. After this is done, a callback is fired to allow you to update your app.

Calling Clarity Contract Functions

Once you have a Clarity smart contract built and deployed, you'll naturally want to allow your app's users to interact with it.

To initiate a contract call transaction, use the openContractCall function.

import { openContractCall } from '@blockstack/connect';

// While in beta, you must provide this option:
const authOrigin = 'https://deploy-preview-301--stacks-authenticator.netlify.app';

// Here's an example of options:
const myStatus = 'hey there';
const options = {
  contractAddress: 'ST22T6ZS7HVWEMZHHFK77H4GTNDTWNPQAX8WZAKHJ',
  contractName: 'status',
  functionName: 'write-status!',
  functionArgs: [
    {
      type: 'buff',
      value: myStatus,
    }
  ],
  authOrigin,
  appDetails: {
    name: 'SuperApp',
    icon: 'https://example.com/icon.png'
  },
  finished: (data) => {
    console.log('TX ID:', data.txId);
    console.log('Raw TX:', data.txRaw);
  },
};

await openContractCall(opts);

When calling openContractCall, you need to specify a few details. Here is the exact interface that describes what options you have:

interface ContractCallOptions {
  contractAddress: string;
  functionName: string;
  contractName: string;
  functionArgs?: any[];
  authOrigin?: string;
  appDetails: {
    name: string;
    icon: string;
  };
  finished: (data: FinishedTxData) => void;
}

parameter	type	optional	description
contractAddress	string	false	The Stacks address that published this contract
contractName	string	false	The name that was used when publishing this contract
functionName	string	false	The name of the function you're calling. This needs to be a public function.
functionArgs	array	false	The arguments you're calling the function with. You'll need to provide the Clarity type with each argument. See the below section for details. Defaults to [].
appDetails	object	false	A dictionary that includes name and icon
finished	function	false	A callback that is fired when the transaction is signed and broadcasted. Your callback will receive an object back with a txId and a txRaw, both of which are strings.
authOrigin	string	true	The location of the authenticator. This is only necessary when developing the authenticator locally, or when using beta features. Defaults to "https://app.blockstack.org".

Passing Clarity types with function arguments

To be able to serialize your transaction properly, you need to provide the appropriate Clarity type with each argument. These types are named the same as they are in Clarity. The value that you pass must be a string. The types you can pass are:

• uint - i.e. "240"
• int - i.e. "12"
• bool - can be "true", "false", "0" or "1"
• buff - i.e. "asdf"
• principal - This can be a contract principal, or a standard principal. Read more about principals. Examples: "ST22T6ZS7HVWEMZHHFK77H4GTNDTWNPQAX8WZAKHJ" or "ST22T6ZS7HVWEMZHHFK77H4GTNDTWNPQAX8WZAKHJ.my-contract".

Using these types, each argument is an object with the keys type and value. For example:

const functionArguments = [
  {
    type: 'buff',
    value: 'hello, world'
  },
  {
    type: 'uint',
    value: '1'
  }
]

If you're using Typescript, these Clarity types can be imported as ContractCallArgumentType from @blockstack/connect.

Stacks (STX) Token Transfers

STX token transfers can be initiated with the openSTXTransfer function.

import { openSTXTransfer } from '@blockstack/connect';

// While in beta, you must provide this option:
const authOrigin = 'https://deploy-preview-301--stacks-authenticator.netlify.app';

openSTXTransfer({
  recipient: 'ST2EB9WEQNR9P0K28D2DC352TM75YG3K0GT7V13CV',
  amount: '100',
  memo: 'Testing STX Transfers!',
  authOrigin,
  appDetails: {
    name: 'SuperApp',
    icon: 'https://example.com/icon.png'
  },
  finished: data => {
    console.log(data.txId);
  },
});

When calling openSTXTransfer, you need to specify a few details. Here are the options you have:

interface STXTransferOptions {
  recipient: string;
  amount: string;
  memo?: string;
  authOrigin?: string;
  appDetails: {
    name: string;
    icon: string;
  };
  finished: (data: FinishedTxData) => void;
}

parameter	type	optional	description
recipient	string	false	The STX Address for the recipient of this STX transfer
amount	string	false	The amount of microstacks (µSTX) to be transferred. This argument is a string to prevent floating point errors. There are 1,000,000 µSTX per STX.
memo	string	true	An optional memo to include in the transaction.
appDetails	object	false	A dictionary that includes name and icon
finished	function	false	A callback that is fired when the transaction is signed and broadcasted. Your callback will receive an object back with a txId and a txRaw, both of which are strings.
authOrigin	string	true	The location of the authenticator. This is only necessary when developing the authenticator locally, or when using beta features. Defaults to "https://app.blockstack.org".

Deploying Clarity Contracts

To allow your app's users to deploy arbitrary Clarity contracts, use the openContractDeploy method.

import { openContractDeploy } from '@blockstack/connect';

const codeBody = '(begin (print "hello, world"))';
// While in beta, you must provide this option:
const authOrigin = 'https://deploy-preview-301--stacks-authenticator.netlify.app';

openContractDeploy({
  contractName: 'my-contract-name',
  codeBody,
  authOrigin,
  appDetails: {
    name: 'SuperApp',
    icon: 'https://example.com/icon.png'
  },
  finished: (data) => {
    console.log(data.txId);
  }
})

Here is the interface for the options you can provide to openContractDeploy:

interface ContractDeployOptions {
  codeBody: string;
  contractName: string;
  authOrigin?: string;
  appDetails: {
    name: string;
    icon: string;
  };
  finished: (data: FinishedTxData) => void;
}

parameter	type	optional	description
codeBody	string	false	The Clarity source code for this contract
contractName	string	false	The name for this contract
appDetails	object	false	A dictionary that includes name and icon
finished	function	false	A callback that is fired when the transaction is signed and broadcasted. Your callback will receive an object back with a txId and a txRaw, both of which are strings.
authOrigin	string	true	The location of the authenticator. This is only necessary when developing the authenticator locally, or when using beta features. Defaults to "https://app.blockstack.org".

Usage in React Apps

Make sure you follow the setup instructions first. When you're using useConnect, you don't have to specify appDetails - we'll pick that up from your existing configuration.

Each transaction signing method is exposed through the useConnect hook, but they're prefixed with do instead of open, to remain consistent with our React action naming standards.

import { useConnect } from '@blockstack/connect';

const MyComponent = () => {
  const { doContractCall } = useConnect();

  const onClick = async () => {
    const opts = { /** See examples above */};
    await doContractCall(opts);
  }

  return (
    <span onClick={onClick}>Call my contract</span>
  );
};