dapp-core

A library that holds the core functional logic of a dapp on the Elrond Network

See Dapp template for live demo or checkout usage in the Github repo

Installation

The library can be installed via npm or yarn.

npm install @elrondnetwork/dapp-core

or

yarn add @elrondnetwork/dapp-core

If you need only the dapp-core basic logic, without the additional UI, consider using the --no-optional flag. This will not install the packages needed for the optional UI components.

npm install @elrondnetwork/dapp-core --no-optional

or

yarn add @elrondnetwork/dapp-core --no-optional

Usage

dapp-core aims to abstract and simplify the process of interacting with users' wallets and with the Elrond Network, allowing developers to easily get started with a new application or integrate dapp-core into an existing application.

This library covers two main areas: User Identity and Transactions. The API for interacting with library's logic is exposed via hooks and methods that can be called for logging in the user, getting the status of the user or sending transactions.

However, to simplify usage even further, the library also comes with a default UI that already uses these hooks and methods under the hood. These UI elements can be easily customized with custom css classes.

The default UI is exposed via the DappUI object.

import { DappUI } from "@elrondnetwork/dapp-core";

More on this below.

Prerequisites

There are a couple of requirements that need to be met for the application to work properly.

If you experience bugs, please make sure that you read these, before opening an issue

React

React

This library was built for applications that use React, it might not be suitable for usage with other libraries or frameworks.

DappProvider

DappProvider

You need to wrap your application with the DappProvider component, which is exported by the library, as we need to create a global Context to be able to manipulate the data.

• import the Provider:

import { DappProvider } from "@elrondnetwork/dapp-core";

• Wrap your application with this Provider.

<DappProvider
    environment="devnet"
    customNetworkConfig={customNetworkConfig}
>

environment is a required key that is needed to configure the app's endpoints for a specific environment. Accepted values are testnet, devnet and mainnet

DappProvider also accepts an optional customNetworkConfig object with a couple of keys. This allows using different APIs and different connection providers to configure your network configuration.

All keys are optional

{
  id?: string;
  name?: string;
  egldLabel?: string;
  egldDenomination?: string;
  decimals?: string;
  gasPerDataByte?: string;
  walletConnectDeepLink?: string; - a string that will create a deeplink for an application that is used on a mobile phone, instead of generating the login QR code.
  walletConnectBridgeAddresses?: string; - a string that is used to establish the connection to walletConnect library;
  walletAddress?: string;
  apiAddress?: string;
  explorerAddress?: string;
  apiTimeout?: 4000;
}

UI Wrappers

UI Wrappers

The library exposes a couple of Components that are connected to the redux store and are used to display various elements when something happens inside the app:

• TransactionsToastList will display new transactions in nice toasts at the bottom of the screen. This component is fully customizable.

  import {DappUI} from "@elrondnetwork/dapp-core";

  <App>
    <DappUI.TransactionsToastList
    toastId?: string,
    title: string,
    shouldRenderDefaultCss?: boolean,
    className?: string
    />
    <Content/>
  </App>

• SignTransactionsModals will show a modal when a new transaction is submitted, prompting the user to verify and sign it.

Important! This is required to make transactions work, except when you use hooks to sign the transactions manually (more on this below).

  import {DappUI} from "@elrondnetwork/dapp-core";

  <App>
    <DappUI.SignTransactionsModals />
    <Content/>
  </App>

NotificationModal Will show a modal to the user with various warnings and errors.

  import {DappUI} from "@elrondnetwork/dapp-core";

  <App>
    <DappUI.NotificationModal />
    <Content/>
  </App>

If you want to show custom notifications, you can use the useGetNotification hook to get the notifications (like insufficient funds, errors etc).

UI css import

UI css import

To properly apply the default styles to Dapp Core Components, you need to import the bundled css into your App's entry point.

import ...

import '@elrondnetwork/dapp-core/dist/index.css';

export default function App() {
...

User Identity

Dapp-core makes logging in and persisting user's session easy and hassle-free.

A handy component is AuthenticatedRoutesWrapper, which can be used to protect certain routes and redirect the user to login page if the user is not authenticated.

Import from dapp-core:

import { AuthenticatedRoutesWrapper} from "@elrondnetwork/dapp-core";

Use with routes:

  <AuthenticatedRoutesWrapper
    routes={routes}
    unlockRoute={routeNames.unlock}
  >
    {appContent}
  </AuthenticatedRoutesWrapper>

routes should be an array with objects with a signature similar to this:

{
    path: "/dashboard",
    title: "Dashboard",
    component: Dashboard,
    authenticatedRoute: true,
  }

The important parts that makes this component work are the flag authenticatedRoute: true and the key path, which means that this route should be accessible only to authenticated users.

Login UI

Login UI

There are a couple of very handy React components that can be used to login the user and protect certain routes if the user is not logged in.

Under the DappUI object mentioned above, you can find 4 buttons (one for each provider) which abstract away all the logic of loggin in the user and render the default UI. These buttons can be easily customized with a custom css class. The exported buttons are:

• DappUI.ExtensionLoginButton
• DappUI.WalletConnectLoginButton
• DappUI.LedgerLoginButton
• DappUI.WebWalletLoginButton

example:

<DappUI.ExtensionLoginButton
  callbackRoute="/dashboard"
  buttonClassName="extension-login"
  loginButtonText="Extension login"
/>

They can also be used with children

<DappUI.ExtensionLoginButton
  callbackRoute="/dashboard"
  buttonClassName="extension-login"
  loginButtonText="Extension login"
>
  <>
    <icon/>
    <p>Login text</p>
  <>
</DappUI.ExtensionLoginButton

WalletConnectLoginButton and LedgerLoginButton will trigger a modal with a QR code and the ledger login UI, respectively. These are automatically triggered by the buttons.

If, however, you want access to these containers without the buttons, you can easily import and use them.

<DappUI.WalletConnectLoginContainer
  callbackRoute={callbackRoute}
  loginButtonText="Login with Maiar"
  title = 'Maiar Login',
  logoutRoute = '/unlock',
  className = 'wallect-connect-login-modal',
  lead = 'Scan the QR code using Maiar',
  shouldRenderDefaultCss={shouldRenderDefaultCss}
  wrapContentInsideModal={wrapContentInsideModal}
  redirectAfterLogin={redirectAfterLogin}
  token={token}
  onClose={onClose}
  />

<DappUI.LedgerLoginContainer
  callbackRoute: string;
  className?: string;
  shouldRenderDefaultCss?: boolean;
  wrapContentInsideModal?: boolean;
  redirectAfterLogin?: boolean;
  token?: string;
  onClose?: () => void;
  />

All login buttons and hooks accept a prop called redirectAfterLogin which specifies of the user should be redirected automatically after login. The default value for this boolean is false, since most apps listen for the "isLoggedIn" boolean and redirect programmatically.

Also, for a quicker setup, the DappUI object exports an DappUI.UnlockPage component, which contains all 4 buttons.

Another handly component is DappUI.AuthenticatedRoutesWrapper, which can be used to protect certain routes and redirect the user to login page if the user is not authenticated.

Import from dapp-core:

import { AuthenticatedRoutesWrapper} from "@elrondnetwork/dapp-core";

Use with routes:

<AuthenticatedRoutesWrapper
    routes={routes}
    unlockRoute={routeNames.unlock}
  >
    {appContent}
  </AuthenticatedRoutesWrapper>

routes should be an array with objects with a signature similar to this:

{
    path: "/dashboard",
    title: "Dashboard",
    component: Dashboard,
    authenticatedRoute: true,
  }

The important parts that makes this component work are the flag authenticatedRoute: true and the key path, which means that this route should be accessible only to authenticated users.

Login hooks

Login hooks

This area covers the login hooks, which expose a trigger function and the login data, ready to be rendered.

These hooks are exposed by the loginServices object, which can be imported from dapp-core:

import {loginServices} from @elrondnetwork/dapp-core

There are 4 available hooks:

• useExtensionLogin
• useWalletConnectLogin
• useLedgerLogin
• useWebWalletLogin

All hooks have the same response signature:

return type is as follows:

const [triggerFunction, genericLoginReturnType, customLoginReturnType] = useLoginHook({
    callbackRoute,
    logoutRoute
  });

• initiateLogin is a function that needs to be called for the login flow to be initiated;
• genericLoginReturnType is an object that is exactly the same for all hooks:

{
  error: string,
  loginFailed: boolean,
  isLoading: boolean,
  isLoggedIn: boolean
}

• customLoginReturnType is an object that is custom for each hook and returns specific data for that login:

  • null for useExtensionLogin;

  • null for useWebWalletConnect;

  • { uriDeepLink: string, qrCodeSvg: svgElement } for useWalletConnectLogin;

{
  accounts: string[];
  showAddressList: boolean;
  startIndex: number;
  selectedAddress: SelectedAddress | null;
  onGoToPrevPage: () => void;
  onGoToNextPage: () => void;
  onSelectAddress: (address: SelectedAddress | null) => void;
  onConfirmSelectedAddress: () => void;
}

for useLedgerLogin;

Reading User State

Reading User State

Once logged in, the user's session is persisted and can be read and deleted via a couple of handy functions.

For logging out, the library exposes a simple function called logout, which can be called to clear the user data.

the function accepts 2 arguments:

• callbackUrl: string (optional) the url to redirect the user to after logging him out
• onRedirect: (callbackUrl: string) => void (optional) a function that will be called instead of redirecting the user. This allows you to control how the redirect is done, for example, with react-router-dom, instead of window.location.href assignment. Important this function will not be called for web wallet logout

You can opt-in for using the useIdleTimer hook, which logs out the user after a period of inactivity (default set to 10 minutes). Optionally it accepts an onLogout function that fulfills your dapp's specific logout business logic. Make sure to call the above logout function inside this onLogout callback.

There are 2 ways of reading the user current state: hooks (to be used inside components and for reacting to changes in the data) and simple functions (for reading data outside of React components or inside handlers).

• hooks: useGetLoginInfo, useGetAccountInfo, useGetNetworkConfig;
• functions: getAccount, getAccountBalance, getAccountShard, getAddress, getIsLoggedIn;

Transactions

The dapp-core library exposes a straight-forward way of sending transactions and tracking their status, with a couple of handy UI components;

Sending Transactions

Sending Transactions

The API for sending transactions is a function called sendTransactions:

import { sendTransactions } from "@elrondnetwork/dapp-core";

It can be used to send a transaction with minimum information:

const { sessionId, error } = await sendTransactions({
    transactions: [
        {
          value: '1000000000000000000',
          data: 'ping',
          receiver: contractAddress
        },
      ],
    callbackRoute?: string // (optional, defaults to window.location.pathname) the route to be redirected to after signing. Will not redirect if the user is already on the specified route;
    transactionsDisplayInfo: TransactionsDisplayInfoType // (optional, default to null) custom message for toasts texts;
    minGasLimit?: number (optional, defaults to 50_000);
    sessionInformation?: any (optional, defaults to null) extra sessionInformation that will be passed back to you via getSignedTransactions hook;
    signWithoutSending?: boolean // (optional, defaults to false), the transaction will be signed without being sent to the blockchain;
    completedTransactionsDelay?: number // delay the transaction status from going into "successful" state;
    redirectAfterSigning?: boolean // (optional, defaults to true), whether to redirect to the provided callbackRoute;
    });

It returns a Promise that will be fulfilled with {error?: string; sessionId: string | null;}

sessionId is the transaction's batch id which can be used to track a transaction's status and react to it.

Important! For the transaction to be signed, you will have to use either SignTransactionsModals defined above, in the Prerequisites section, or the useSignTransactions hook defined below. If you don't use one of these, the transactions won't be signed

Transaction Signing Flow

Transaction Signing Flow

Once a transaction has been submitted, you have to use either the SignTransactionsModals or the useSignTransactions hook, for the user to be prompted in his provider (Extension, Maiar etc) to sign the transaction.

If you don't want to use the default modals that appear for the user when the signing process happens, you have to use the useSignTransactions hook to sign those transactions.

 const {
    callbackRoute,
    transactions,
    error,
    sessionId,
    onAbort,
    hasTransactions
  } = useSignTransactions();

This hook will let you know if there are any transactions and you can programmatically abort the signing process.

We suggest displaying a message on the screen that confirms the transaction that needs to be signed.

You can also get the provider via

  const { providerType } = useGetAccountProvider();

and use that to display an appropriate message to the user.

For ledger, signing a transaction is simple if you're using the SignTransactionsModal component.

It is fully customizable and will take care of walking the user through the signing flow.

If, however, you want to implement a different experience, you will have to use the useSignTransactionsWithLedger hook.

it accepts the following props:

{
  onCancel: () => void;
}

and returns an object with the following keys:

{
  onSignTransaction: () => void;
  onNext: () => void;
  onPrev: () => void;
  waitingForDevice: boolean;
  onAbort: (e: React.MouseEvent) => void;
  isLastTransaction: boolean;
  currentStep: number;
  signedTransactions?: Record<string, Transaction>;
  currentTransaction: {
      transaction: Transaction;
      transactionTokenInfo: {
          tokenId: string;
          amount: string;
          receiver: string;
          type?: string;
          nonce?: string;
          multiTxData?: string;
      };
      isTokenTransaction: boolean;
      tokenDenomination: number;
      dataField: string;
  };
  }

Tracking a transaction

Tracking a transaction

The library exposes a hook called useTrackTransactionStatus under the object transactionServices.

import {transactionServices} from @elrondnetwork/dapp-core;

const transactionStatus = transactionServices.useTrackTransactionStatus({
  transactionId: sessionId,
  onSuccess,
  onFail,
  onCancelled,
});

transactionStatus has the following information about the transaction:

{
  isPending,
  isSuccessful,
  isFailed,
  isCancelled,
  errorMessage,
  status,
  transactions
}

It's safe to pass in null as a sessionId, so if the transaction wasn't yet sent, the hook will just return an empty object.

Tracking transactions' statuses

Tracking transactions' statuses

Dapp-core also exposes a number of handy hooks for tracking all, pending, failed, successful and timed out transactions.

Use:

• useGetPendingTransactions to get a list of all pending transactions.
• useGetSuccessfulTransactions to get a list of all successful transactions.
• useGetFailedTransactions to get a list of all pending transactions.

An especially useful hook called useGetActiveTransactionsStatus will keep you updated with the status of all transactions at a certain point in time.

it's return signature is

{
  hasActiveTransactions: boolean - the user has at least 1 active transactions in one of the states described below;
  pending: boolean - at least one transaction is pending;
  timedOut: boolean = there are no pending transactions and at least one has timed out;
  fail: boolean - there are no pending and no timedOut transactions and at least one has failed;
  success: boolean - all transactions are successful and all smart contract calls have been processed successfully;
}

Transaction Toasts UI

Transaction Toasts UI

dapp-core also exposes a toast component for tracking transactions that uses the above mentioned hooks and displays toasts with transactions statuses.

The toasts list is exposed via DappUI.TransactionsToastList component and can be used just by rendering it inside the application.

<App>
  <Router/>
  <DappUI.TransactionsToastList />
</App>

Important: This has to be inside the <DappProvider/> children.

Removing transactions manually

Removing transactions manually

Dapp-core takes care to change transactions' statuses and removes them when needed, but if you need to do this manually, you can use the exposed functions for this:

transactionServices.removeTransactionsToSign(sessionId);
transactionServices.removeSignedTransaction(sessionId);
transactionServices.removeAllTransactionsToSign();
transactionServices.removeAllSignedTransactions();

Roadmap

See the open issues for a list of proposed features (and known issues).

Contributing

Contributions are what make the open source community such an amazing place to be learn, inspire, and create. Any contributions you make are greatly appreciated.

One can contribute by creating pull requests, or by opening issues for discovered bugs or desired features.

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature/AmazingFeature)
3. Commit your Changes (git commit -m 'Add some AmazingFeature')
4. Push to the Branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

Developers

The Elrond Team.

License

GPL-3.0-or-later