diff --git a/v3/tutorials/02-proof-of-existence/index.mdx b/v3/tutorials/02-proof-of-existence/index.mdx index 97550de82..0b37fd920 100644 --- a/v3/tutorials/02-proof-of-existence/index.mdx +++ b/v3/tutorials/02-proof-of-existence/index.mdx @@ -429,152 +429,149 @@ This React component enables you to expose the proof-of-existence capabilities a 1. Copy and paste the following code into the`src/TemplateModule.js` file: - ```javascript - // React and Semantic UI elements. - import React, { useState, useEffect } from 'react' - import { Form, Input, Grid, Message } from 'semantic-ui-react' - - // Pre-built Substrate front-end utilities for connecting to a node - // and making a transaction. - import { useSubstrate } from './substrate-lib' - import { TxButton } from './substrate-lib/components' - - // Polkadot-JS utilities for hashing data. - import { blake2AsHex } from '@polkadot/util-crypto' - - // Main Proof Of Existence component is exported. - export function Main(props) { - // Establish an API to talk to the Substrate node. - const { api } = useSubstrate() - // Get the selected user from the `AccountSelector` component. - const { accountPair } = props - // React hooks for all the state variables we track. - // Learn more at: https://reactjs.org/docs/hooks-intro.html - const [status, setStatus] = useState('') - const [digest, setDigest] = useState('') - const [owner, setOwner] = useState('') - const [block, setBlock] = useState(0) - // Our `FileReader()` which is accessible from our functions below. - let fileReader - // Takes our file, and creates a digest using the Blake2 256 hash function - const bufferToDigest = () => { - // Turns the file content to a hexadecimal representation. - const content = Array.from(new Uint8Array(fileReader.result)) - .map(b => b.toString(16).padStart(2, '0')) - .join('') - const hash = blake2AsHex(content, 256) - setDigest(hash) - } - - // Callback function for when a new file is selected. - const handleFileChosen = file => { - fileReader = new FileReader() - fileReader.onloadend = bufferToDigest - fileReader.readAsArrayBuffer(file) - } - - // React hook to update the owner and block number information for a file - useEffect(() => { - let unsubscribe - // Polkadot-JS API query to the `proofs` storage item in our pallet. - // This is a subscription, so it will always get the latest value, - // even if it changes. - api.query.templateModule - .proofs(digest, result => { - // Our storage item returns a tuple, which is represented as an array. - setOwner(result[0].toString()) - setBlock(result[1].toNumber()) - }) - .then(unsub => { - unsubscribe = unsub - }) - return () => unsubscribe && unsubscribe() - // This tells the React hook to update whenever the file digest changes - // (when a new file is chosen), or when the storage subscription says the - // value of the storage item has updated. - }, [digest, api.query.templateModule]) - - // We can say a file digest is claimed if the stored block number is not 0 - function isClaimed() { - return block !== 0 - } - - // The actual UI elements which are returned from our component. - return ( - -

Proof of Existence

- {/* Show warning or success message if the file is or is not claimed. */} -
- - {/* File selector with a callback to `handleFileChosen`. */} - handleFileChosen(e.target.files[0])} - /> - {/* Show this message if the file is available to be claimed */} - - {/* Show this message if the file is already claimed. */} - - - {/* Buttons for interacting with the component. */} - - {/* Button to create a claim. Only active if a file is selected, and not already claimed. Updates the `status`. */} - - {/* Button to revoke a claim. Only active if a file is selected, and is already claimed. Updates the `status`. */} - - - {/* Status message about the transaction. */} -
{status}
-
- - ) - } - - export default function TemplateModule(props) { - const { api } = useSubstrate() - return api.query.templateModule && api.query.templateModule.proofs ? ( -
- ) : null - } - ``` + ```javascript + import React, { useEffect, useState } from 'react' + import { Form, Input, Grid, Message } from 'semantic-ui-react' + + // Pre-built Substrate front-end utilities for connecting to a node + // and making a transaction. + import { useSubstrateState } from './substrate-lib' + import { TxButton } from './substrate-lib/components' + + // Polkadot-JS utilities for hashing data. + import { blake2AsHex } from '@polkadot/util-crypto' + + // Main Proof Of Existence component is exported. + function Main(props) { + // Establish an API to talk to the Substrate node. + const { api, currentAccount } = useSubstrateState() + // React hooks for all the state variables we track. + // Learn more at: https://reactjs.org/docs/hooks-intro.html + const [status, setStatus] = useState('') + const [digest, setDigest] = useState('') + const [owner, setOwner] = useState('') + const [block, setBlock] = useState(0) + + // Our `FileReader()` which is accessible from our functions below. + let fileReader + // Takes our file, and creates a digest using the Blake2 256 hash function + const bufferToDigest = () => { + // Turns the file content to a hexadecimal representation. + const content = Array.from(new Uint8Array(fileReader.result)) + .map(b => b.toString(16).padStart(2, '0')) + .join('') + const hash = blake2AsHex(content, 256) + setDigest(hash) + } + + // Callback function for when a new file is selected. + const handleFileChosen = file => { + fileReader = new FileReader() + fileReader.onloadend = bufferToDigest + fileReader.readAsArrayBuffer(file) + } + + // React hook to update the owner and block number information for a file + useEffect(() => { + let unsubscribe + // Polkadot-JS API query to the `proofs` storage item in our pallet. + // This is a subscription, so it will always get the latest value, + // even if it changes. + api.query.templateModule + .proofs(digest, result => { + // Our storage item returns a tuple, which is represented as an array. + setOwner(result[0].toString()) + setBlock(result[1].toNumber()) + }) + .then(unsub => { + unsubscribe = unsub + }) + return () => unsubscribe && unsubscribe() + // This tells the React hook to update whenever the file digest changes + // (when a new file is chosen), or when the storage subscription says the + // value of the storage item has updated. + }, [digest, api.query.templateModule]) + + // We can say a file digest is claimed if the stored block number is not 0 + function isClaimed() { + return block !== 0 + } + + // The actual UI elements which are returned from our component. + return ( + +

Proof of Existence

+ {/* Show warning or success message if the file is or is not claimed. */} +
+ + {/* File selector with a callback to `handleFileChosen`. */} + handleFileChosen(e.target.files[0])} + /> + {/* Show this message if the file is available to be claimed */} + + {/* Show this message if the file is already claimed. */} + + + {/* Buttons for interacting with the component. */} + + {/* Button to create a claim. Only active if a file is selected, and not already claimed. Updates the `status`. */} + + {/* Button to revoke a claim. Only active if a file is selected, and is already claimed. Updates the `status`. */} + + + {/* Status message about the transaction. */} +
{status}
+
+ + ) + } + + export default function TemplateModule(props) { + const { api } = useSubstrateState() + return api.query.templateModule ?
: null + } + ``` 1. Save your changes and close the file. 1. Start the front-end template by running the following command: - ```bash - yarn start - ``` + ```bash + # If you haven't installed the dependencies + yarn install + # Start the project + yarn start + ``` This will open up a new tab with the front-end serving at **http://localhost:8000**.