feat: add a simple message signing and verification page to the explorer

app/components/Navbar.tsx

@@ -15,6 +15,7 @@ export function Navbar() {
     const homePath = useClusterPath({ pathname: '/' });
     const supplyPath = useClusterPath({ pathname: '/supply' });
     const inspectorPath = useClusterPath({ pathname: '/tx/inspector' });
+    const messagePath = useClusterPath({ pathname: '/message' });
     const selectedLayoutSegment = useSelectedLayoutSegment();
     const selectedLayoutSegments = useSelectedLayoutSegments();
     return (
@@ -48,16 +49,26 @@ export function Navbar() {
                         </li>
                         <li className="nav-item">
                             <Link
-                                className={`nav-link${
-                                    selectedLayoutSegments[0] === 'tx' && selectedLayoutSegments[1] === '(inspector)'
+                                className={`nav-link${selectedLayoutSegments[0] === 'tx' && selectedLayoutSegments[1] === '(inspector)'
                                         ? ' active'
                                         : ''
-                                }`}
+                                    }`}
                                 href={inspectorPath}
                             >
                                 Inspector
                             </Link>
                         </li>
+                        <li className="nav-item">
+                            <Link
+                                className={`nav-link${selectedLayoutSegments[0] === 'tx' && selectedLayoutSegments[1] === '(message)'
+                                        ? ' active'
+                                        : ''
+                                    }`}
+                                href={messagePath}
+                            >
+                                Message
+                            </Link>
+                        </li>
                     </ul>
                 </div>
 

app/components/message/MessageContext.tsx

@@ -0,0 +1,33 @@
+import { WalletAdapterNetwork } from "@solana/wallet-adapter-base";
+import {
+  ConnectionProvider,
+  WalletProvider,
+} from "@solana/wallet-adapter-react";
+import { WalletModalProvider } from "@solana/wallet-adapter-react-ui";
+import { UnsafeBurnerWalletAdapter } from '@solana/wallet-adapter-wallets';
+import { clusterApiUrl } from "@solana/web3.js";
+import React, { FC, ReactNode, useMemo } from "react";
+
+export const SignerWalletContext: FC<{ children: ReactNode }> = ({ children }) => {
+  // Always use devnet, this page never needs to use RPC
+  const network = WalletAdapterNetwork.Devnet;
+  const endpoint = useMemo(() => clusterApiUrl(network), [network]);
+
+  const wallets = useMemo(
+    () => [
+      new UnsafeBurnerWalletAdapter(),
+    ],
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+    [network]
+  );
+
+  return (
+    <ConnectionProvider endpoint={endpoint}>
+      <WalletProvider wallets={wallets} autoConnect>
+        <WalletModalProvider>
+          {children}
+        </WalletModalProvider>
+      </WalletProvider>
+    </ConnectionProvider>
+  );
+};

app/components/message/MessageForm.tsx

@@ -0,0 +1,209 @@
+import { ed25519 } from "@noble/curves/ed25519";
+import { PublicKey } from "@solana/web3.js";
+import bs58 from 'bs58';
+import dynamic from 'next/dynamic';
+import { SetStateAction, useCallback, useEffect, useMemo, useState } from "react";
+
+import { MeteredMessageBox } from "./MeteredMessageBox";
+import { SIGNING_DOMAIN, SigningContext, SignMessageBox } from "./SignMessageButton";
+
+const ConnectButton = dynamic(async () => ((await import('@solana/wallet-adapter-react-ui')).WalletMultiButton), { ssr: false });
+
+export type ReportMessageVerification = (verified: boolean, show?: boolean, message?: string) => void;
+
+const MAX_MSG_LENGTH = 1500;
+
+function getPluralizedWord(count: number): string {
+    return count === 1 ? "character" : "characters";
+}
+
+function sanitizeInput(input: string) {
+    input = input.replace(/<script.*?>.*?<\/script>/gi, '');
+    if (input.length > MAX_MSG_LENGTH) {
+        console.log("Message length limit reached. Truncating...");
+        input = input.substring(0, MAX_MSG_LENGTH);
+    }
+    return input;
+}
+
+export const MessageForm = (props: { reportVerification: ReportMessageVerification }) => {
+    const [address, setAddress] = useState("");
+    const [message, setMessage] = useState("");
+    const [signature, setSignature] = useState("");
+    const [addressError, setAddressError] = useState(false);
+    const [verified, setVerifiedInternal] = useState(false);
+
+    const setVerified = useCallback((verified: boolean, show = false, message = "") => {
+        setVerifiedInternal(verified);
+        props.reportVerification(verified, show, message);
+    }, [props]);
+
+    const handleAddressChange = useCallback((event: { target: { value: SetStateAction<string>; }; }) => {
+        setVerified(false);
+        const update = event.target.value;
+        setAddress(update);
+
+        try {
+            let isError = false;
+            if (update.length > 0 && !PublicKey.isOnCurve(update)) {
+                isError = true;
+            }
+            setAddressError(isError);
+        } catch (error: unknown) {
+            if (error instanceof Error) {
+                console.error(error.message);
+            }
+            setAddressError(true);
+        }
+        // eslint-disable-next-line react-hooks/exhaustive-deps
+    }, []);
+
+    const handleSignatureChange = useCallback((event: { target: { value: SetStateAction<string>; }; }) => {
+        setVerified(false);
+        setSignature(event.target.value);
+        // eslint-disable-next-line react-hooks/exhaustive-deps
+    }, []);
+
+    const handleInputChange = useCallback((event: { target: { value: string; }; }) => {
+        setVerified(false);
+        setMessage(sanitizeInput(event.target.value));
+        // eslint-disable-next-line react-hooks/exhaustive-deps
+    }, []);
+
+    const handleVerifyClick = useCallback(() => {
+        try {
+            const messageBytes = new TextEncoder().encode(SIGNING_DOMAIN + message);
+            const verified = ed25519.verify(bs58.decode(signature), messageBytes, bs58.decode(address));
+            if (!verified) throw new Error("Message verification failed!");
+            setVerified(true)
+        } catch (error) {
+            console.error("Message verification failed!");
+            setVerified(false, true);
+        }
+    }, [setVerified, address, message, signature]);
+
+    useEffect(() => {
+        const urlParams = new URLSearchParams(window.location.search);
+        const urlAddress = urlParams.get('address');
+        const urlMessage = urlParams.get('message');
+        const urlSignature = urlParams.get('signature');
+
+        if (urlAddress && urlMessage && urlSignature) {
+            handleAddressChange({ target: { value: urlAddress } });
+            handleInputChange({ target: { value: urlMessage } });
+            handleSignatureChange({ target: { value: urlSignature } });
+        }
+    }, [handleAddressChange, handleInputChange, handleSignatureChange]);
+
+    const signingContext = useMemo(() => {
+        return {
+            address,
+            input: message,
+            setAddress: handleAddressChange,
+            setInput: handleInputChange,
+            setSignature: handleSignatureChange,
+            setVerified,
+            signature,
+        } as SigningContext;
+    }, [message, address, signature, handleAddressChange, handleSignatureChange, handleInputChange, setVerified]);
+
+    function writeToClipboard() {
+        const encodedAddress = encodeURIComponent(address);
+        const encodedMessage = encodeURIComponent(message);
+        const encodedSignature = encodeURIComponent(signature);
+        const newUrl = `${window.location.origin}${window.location.pathname}?address=${encodedAddress}&message=${encodedMessage}&signature=${encodedSignature}`;
+        navigator.clipboard.writeText(newUrl).catch(err => {
+            console.error("Failed to copy to clipboard: ", err);
+        });
+    }
+
+    const placeholder_message = 'Type a message here...';
+    const placeholder_address = 'Enter an address whose signature you want to verify...';
+    const placeholder_signature = 'Paste a signature...';
+    const verifyButtonDisabled = !address || !message || !signature;
+
+    return (
+        <div className="card" >
+            <div className="card-header" style={{ padding: '2.5rem 1.5rem' }}>
+                <div className="row align-items-center d-flex justify-content-between">
+                    <div className="col">
+                        <h2 className="card-header-title">Message Signer</h2>
+                    </div>
+                    <div className="col-auto">
+                        <ConnectButton style={{
+                            borderRadius: '0.5rem',
+                        }} />
+                    </div>
+                </div>
+            </div>
+            <div className="card-header">
+                <h3 className="card-header-title">Address</h3>
+            </div>
+            <div className="card-body">
+                <textarea
+                    rows={2}
+                    onChange={handleAddressChange}
+                    value={address}
+                    className="form-control form-control-auto"
+                    placeholder={placeholder_address}
+                />
+                {addressError && (
+                    <div className="text-warning small mt-2">
+                        <i className="fe fe-alert-circle"></i> Invalid address.
+                    </div>
+                )}
+            </div>
+            <div className="card-header">
+                <h3 className="card-header-title">Message</h3>
+            </div>
+            <div className="card-body">
+                <p className="text-muted small">Make sure you understand what you&apos;re signing. Transaction signing is not allowed. Message signing is free.</p>
+                <MeteredMessageBox
+                    value={message}
+                    onChange={handleInputChange}
+                    placeholder={placeholder_message}
+                    word={getPluralizedWord(MAX_MSG_LENGTH - message.length)}
+                    limit={MAX_MSG_LENGTH}
+                    count={message.length}
+                    charactersremaining={MAX_MSG_LENGTH - message.length} />
+            </div>
+
+            <div className="card-header">
+                <h3 className="card-header-title">Signature</h3>
+            </div>
+            <div className="card-body">
+                <div style={{ display: 'flex', flexDirection: 'column', flexGrow: 1, overflowY: 'auto' }}>
+                    <textarea
+                        rows={2}
+                        onChange={handleSignatureChange}
+                        value={signature}
+                        className="form-control form-control-auto"
+                        placeholder={placeholder_signature}
+                    />
+                </div>
+            </div>
+
+            <div className="card-footer d-flex justify-content-end">
+                <div className="me-2" data-bs-toggle="tooltip" data-bs-placement="top" title={!verified ? "Verify first to enable this action" : ""}>
+                    <button
+                        className="btn btn-primary"
+                        onClick={writeToClipboard}
+                        disabled={!verified}
+                    >
+                        Copy URL
+                    </button>
+                </div>
+                <div className="me-2" data-bs-toggle="tooltip" data-bs-placement="top" title={verifyButtonDisabled ? "Complete the form to enable this action" : ""}>
+                    <button
+                        className="btn btn-primary"
+                        onClick={handleVerifyClick}
+                        disabled={verifyButtonDisabled}
+                    >
+                        Verify
+                    </button>
+                </div>
+                <SignMessageBox className="btn btn-primary me-2" signingcontext={signingContext} />
+            </div>
+        </div >
+    );
+};

app/components/message/MessageSignerPage.tsx

@@ -0,0 +1,75 @@
+'use client';
+
+import '@solana/wallet-adapter-react-ui/styles.css';
+
+import { useEffect, useState } from 'react';
+
+import { SignerWalletContext } from './MessageContext';
+import { MessageForm } from './MessageForm';
+
+export default function MessageSignerPage() {
+    const [verified, setVerifiedInternal] = useState(false);
+    const [openVerifiedSnackbar, showVerifiedSnackBar] = useState(false);
+    const [verificationMessage, setVerificationMessage] = useState("");
+
+    function setVerified(verified: boolean, showSnackBar = false, message = "") {
+        if (verified || showSnackBar) {
+            showVerifiedSnackBar(true);
+        } else {
+            showVerifiedSnackBar(false);
+        }
+        setVerificationMessage(message);
+        setVerifiedInternal(verified);
+    }
+
+    // Auto-dismiss the snackbar after 5 seconds
+    useEffect(() => {
+        if (openVerifiedSnackbar) {
+            const timer = setTimeout(() => {
+                showVerifiedSnackBar(false);
+            }, 3000);
+
+            return () => clearTimeout(timer);
+        }
+    }, [openVerifiedSnackbar]);
+
+    const message = verified
+        ? `Message Verified${verificationMessage ? ": " + verificationMessage : ""}`
+        : `Message Verification Failed${verificationMessage ? ": " + verificationMessage : ""}`;
+
+    return (
+        <SignerWalletContext>
+            <div style={{
+                display: 'flex',
+                flexDirection: 'column',
+                minHeight: 'auto',
+            }}>
+                <div style={{
+                    flex: 1,
+                    overflow: 'auto',
+                }}>
+                    <MessageForm reportVerification={setVerified} />
+                </div>
+            </div>
+            {openVerifiedSnackbar && (
+                <div
+                    className={`alert alert-${verified ? 'success' : 'danger'} alert-dismissible fade show mt-3`}
+                    role="alert"
+                    style={{
+                        alignItems: 'center',
+                        borderRadius: '0.5rem',
+                        boxShadow: '0 4px 12px rgba(0, 0, 0, 0.1)',
+                        display: 'flex',
+                        justifyContent: 'space-between',
+                        margin: '1rem auto',
+                        maxWidth: '600px',
+                        padding: '1rem 1.5rem'
+                    }}
+                    onClick={() => showVerifiedSnackBar(false)}
+                >
+                    {message}
+                </div>
+            )}
+        </SignerWalletContext>
+    );
+}

app/components/message/MeteredMessageBox.tsx

@@ -0,0 +1,29 @@
+import React from 'react';
+
+export type MsgCounterProps = React.TextareaHTMLAttributes<HTMLTextAreaElement> & {
+  word: string;
+  limit: number;
+  count: number;
+  charactersremaining: number;
+};
+
+export const MeteredMessageBox = (props: MsgCounterProps) => {
+  return (
+    <div style={{ display: 'flex', flexDirection: 'column', flexGrow: 1, overflowY: 'auto' }}>
+      <textarea
+        {...props}
+        className={`form-control ${props.className || ''}`}
+        rows={3}
+        maxLength={props.limit}
+      />
+      <div className="d-flex justify-content-between mt-1" style={{ fontSize: '0.875em' }}>
+        <span>
+          {props.charactersremaining} {props.word} remaining
+        </span>
+        <span>
+          {props.count}/{props.limit}
+        </span>
+      </div>
+    </div>
+  );
+};