--- /dev/null
+# event-hashes
+
+This is a minimal web utility to calculate the `keccak256` hashes of the normalized event signatures of all the events in a Solidity code block. This hash can then be used with indexers like Etherscan to search for specific logs in the EVM history.
+
+> [!WARNING]<br>
+> This tool won't work with [user-defined value types](https://docs.soliditylang.org/en/latest/types.html#user-defined-value-types). For events that include these types, you must manually convert the user-defined value type into its equivalent primitive type.
+
+## Example
+
+
+
+Given the [standard ERC-20 `Transfer` event](https://eips.ethereum.org/EIPS/eip-20#events):
+
+```
+event Transfer(address indexed _from, address indexed _to, uint256 _value)
+```
+
+The tool will normalize the event signature (i.e., remove spaces, input names, and extraneous keywords):
+
+```
+Transfer(address,address,uint256)
+```
+
+Then calculate the `keccak256` hash of the UTF-8 encoded bytes of the normalized signature:
+
+```
+0xddf252ad1be2c89b69c2b068fc378daa952ba7f163c4a11628f55a4df523b3ef
+```
+
+This hash may then be used in another tool to filter a smart contract's logs, e.g. [in Etherscan](https://etherscan.io/address/0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48#events):
+
+
--- /dev/null
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+ <meta charset="UTF-8">
+ <meta name="viewport" content="width=device-width, initial-scale=1.0">
+ <meta name="description" content="A minimal web utility to calculate the Keccak-256 hashes for all the events in a Solidity code block.">
+ <meta property="og:title" content="Event Hashes">
+ <meta property="og:description" content="A minimal web utility to calculate the Keccak-256 hashes for all the events in a Solidity code block.">
+ <meta property="og:type" content="website">
+ <meta property="og:url" content="https://event-hashes.ardis.lu/">
+ <link rel="icon" href="data:,">
+ <link rel="preload" href="/Inter.woff2" as="font" crossorigin>
+ <link rel="preload" href="/Inter_600.woff2" as="font" crossorigin>
+ <link rel="preload" href="/Inter_700.woff2" as="font" crossorigin>
+ <link rel="modulepreload" href="/keccak256.js">
+ <link rel="icon" href="data:,">
+ <title>Event Hashes</title>
+ <style>
+ @font-face {
+ font-family: 'Inter';
+ font-weight: 400;
+ src: url('/Inter.woff2') format('woff2');
+ }
+
+ @font-face {
+ font-family: 'Inter';
+ font-weight: 600;
+ src: url('/Inter_600.woff2') format('woff2');
+ }
+
+ @font-face {
+ font-family: 'Inter';
+ font-weight: 700;
+ src: url('/Inter_700.woff2') format('woff2');
+ }
+
+ * {
+ margin: 0;
+ box-sizing: border-box;
+ font-family: inherit;
+ font-size: 1rem;
+ }
+
+ :root {
+ font-family: 'Inter', sans-serif;
+ }
+
+ body {
+ min-block-size: 100dvb;
+ margin-inline: 8px;
+ background: hsl(216deg 50% 95%);
+ color: hsl(216deg 50% 5%);
+ display: grid;
+ grid-template-rows: auto 1fr auto;
+ }
+
+ header,
+ footer {
+ margin-block: 36px;
+ display: flex;
+ flex-direction: column;
+ align-items: center;
+ }
+
+ header h1 {
+ font-size: 2rem;
+ }
+
+ header p {
+ text-align: center;
+ }
+
+ main {
+ display: flex;
+ flex-direction: column;
+ inline-size: min(100dvi - 16px, 720px);
+ margin-inline: auto;
+ gap: 8px;
+ }
+
+ label {
+ font-weight: 700;
+ }
+
+ textarea {
+ align-self: center;
+ min-inline-size: 100%;
+ max-inline-size: calc(100dvi - 32px);
+ min-block-size: 15rem;
+ padding: 4px;
+ border-radius: 4px;
+ border: 1px solid hsl(216deg 50% 80%);
+ }
+
+ table {
+ display: none;
+ border-collapse: collapse;
+ overflow-x: auto;
+ align-self: center;
+ }
+
+ tr {
+ transition: background-color 400ms;
+ }
+
+ tr:hover,
+ tr:focus-within {
+ background: hsl(222deg 50% 90%);
+ transition: background-color 200ms;
+ }
+
+ th,
+ td {
+ line-height: 2;
+ padding-block: 8px;
+ padding-inline: 4px 16px;
+ }
+
+ a {
+ font-weight: 700;
+ text-decoration: none;
+ }
+
+ a:hover,
+ a:focus {
+ text-decoration: underline;
+ }
+ </style>
+</head>
+
+<body>
+ <header>
+ <h1>Event Hashes</h1>
+ <p>Enter Solidity code below to calculate the Keccak-256 hashes for all the events.</p>
+ </header>
+
+ <main>
+ <label for="code">Solidity code</label>
+ <textarea id="code" placeholder="event Transfer(address indexed _from, address indexed _to, uint256 _value)" autocomplete="off"></textarea>
+
+ <table>
+ <thead>
+ <tr>
+ <th>Normalized Event Signature</th>
+ <th>Keccak-256 Hash</th>
+ </tr>
+ </thead>
+ <tbody></tbody>
+ </table>
+ </main>
+
+ <footer>
+ <a href="https://github.com/ardislu/event-hashes">GitHub</a>
+ </footer>
+
+ <script type="module">
+ // From noble-hashes v1.3.3
+ import { keccak256 } from '/keccak256.js';
+
+ function normalizeEvent(event) {
+ // Clean all characters that definitely do not affect the signature
+ const commentIndex = event.indexOf('//');
+ event = commentIndex === -1 ? event : event.substring(0, commentIndex);
+ event = event.trim();
+
+ // Split the event name and the event topics
+ const eventRegex = /^(event )?(?<name>[a-zA-Z$_][a-zA-Z0-9$_]*)\((?<topics>.*?)(?!.+\))/;
+ const { name, topics } = eventRegex.exec(event).groups;
+
+ // Drop parameter names and extraneous whitespace, if there are any. Preserves tuple parentheses.
+ // E.g. "(uint abc, uint256, bool test)[]" --> ['(uint', 'uint256', 'bool)[]']
+ const topicArray = topics.split(',').map(topic => {
+ const trimmed = topic.trim();
+ const trailingParens = trimmed.match(/\)*[\[\]]*$/)[0] ?? '';
+ const split = trimmed.split(' ');
+ return `${split[0]}${split.length > 1 ? trailingParens : ''}`;
+ });
+
+ // Convert types from Solidity to ABI (e.g., 'uint' --> 'uint256')
+ // Reference: https://docs.soliditylang.org/en/latest/abi-spec.html#types
+ for (const [index, topic] of topicArray.entries()) {
+ if (/int[1-9]/.test(topic) || /uint[1-9]/.test(topic)) {
+ continue;
+ }
+ topicArray[index] = topic
+ .replace('int', 'int256') // Includes uint --> uint256
+ .replace('contract', 'address')
+ .replace('enum', 'uint8');
+ }
+
+ const types = topicArray.join(',');
+ return `${name}(${types})`;
+ }
+
+ function getEvents(code) {
+ const events = new Set();
+ for (let line of code.split('\n')) {
+ line = line.trim();
+ if (line === '') {
+ continue;
+ }
+ try {
+ const normalizedEvent = normalizeEvent(line);
+ events.add(normalizedEvent);
+ }
+ catch {
+ continue;
+ }
+ }
+ return Array.from(events);
+ }
+
+ function debounce(fn, wait) {
+ let timeoutId;
+ return () => {
+ clearTimeout(timeoutId);
+ timeoutId = setTimeout(fn, wait);
+ }
+ }
+
+ const encoder = new TextEncoder();
+ const textarea = document.querySelector('textarea');
+ const table = document.querySelector('table');
+ const tableBody = document.querySelector('table tbody');
+ textarea.addEventListener('input', debounce(() => {
+ table.style.setProperty('display', 'none');
+ tableBody.innerHTML = '';
+
+ const events = getEvents(textarea.value);
+ if (events.length === 0) {
+ return;
+ }
+
+ for (const event of events) {
+ const byteArray = keccak256(encoder.encode(event));
+ const hash = `0x${[...byteArray].map(b => b.toString(16).padStart(2, '0')).join('')}`;
+ tableBody.insertAdjacentHTML('beforeend', `<tr><td>${event}</td><td>${hash}</td></tr>`);
+ }
+ table.style.setProperty('display', 'revert');
+ }, 250));
+ </script>
+</body>
+
+</html>
\ No newline at end of file
--- /dev/null
+function g(t){if(!Number.isSafeInteger(t)||t<0)throw new Error(`Wrong positive integer: ${t}`)}function R(t){return t instanceof Uint8Array||t!=null&&typeof t=="object"&&t.constructor.name==="Uint8Array"}function b(t,...e){if(!R(t))throw new Error("Expected Uint8Array");if(e.length>0&&!e.includes(t.length))throw new Error(`Expected Uint8Array of length ${e}, not of length=${t.length}`)}function k(t,e=!0){if(t.destroyed)throw new Error("Hash instance has been destroyed");if(e&&t.finished)throw new Error("Hash#digest() has already been called")}function L(t,e){b(t);let n=e.outputLen;if(t.length<n)throw new Error(`digestInto() expects output buffer of length at least ${n}`)}var d=BigInt(4294967295),_=BigInt(32);function V(t,e=!1){return e?{h:Number(t&d),l:Number(t>>_&d)}:{h:Number(t>>_&d)|0,l:Number(t&d)|0}}function A(t,e=!1){let n=new Uint32Array(t.length),r=new Uint32Array(t.length);for(let s=0;s<t.length;s++){let{h:i,l:o}=V(t[s],e);[n[s],r[s]]=[i,o]}return[n,r]}var m=(t,e,n)=>t<<n|e>>>32-n,B=(t,e,n)=>e<<n|t>>>32-n,O=(t,e,n)=>e<<n-32|t>>>64-n,I=(t,e,n)=>t<<n-32|e>>>64-n;var E=t=>new Uint32Array(t.buffer,t.byteOffset,Math.floor(t.byteLength/4));function M(t){return t instanceof Uint8Array||t!=null&&typeof t=="object"&&t.constructor.name==="Uint8Array"}var W=new Uint8Array(new Uint32Array([287454020]).buffer)[0]===68;if(!W)throw new Error("Non little-endian hardware is not supported");function D(t){if(typeof t!="string")throw new Error(`utf8ToBytes expected string, got ${typeof t}`);return new Uint8Array(new TextEncoder().encode(t))}function w(t){if(typeof t=="string"&&(t=D(t)),!M(t))throw new Error(`expected Uint8Array, got ${typeof t}`);return t}var x=class{clone(){return this._cloneInto()}},et={}.toString;function U(t){let e=r=>t().update(w(r)).digest(),n=t();return e.outputLen=n.outputLen,e.blockLen=n.blockLen,e.create=()=>t(),e}function H(t){let e=(r,s)=>t(s).update(w(r)).digest(),n=t({});return e.outputLen=n.outputLen,e.blockLen=n.blockLen,e.create=r=>t(r),e}var[F,j,X]=[[],[],[]],P=BigInt(0),h=BigInt(1),v=BigInt(2),q=BigInt(7),z=BigInt(256),G=BigInt(113);for(let t=0,e=h,n=1,r=0;t<24;t++){[n,r]=[r,(2*n+3*r)%5],F.push(2*(5*r+n)),j.push((t+1)*(t+2)/2%64);let s=P;for(let i=0;i<7;i++)e=(e<<h^(e>>q)*G)%z,e&v&&(s^=h<<(h<<BigInt(i))-h);X.push(s)}var[J,K]=A(X,!0),S=(t,e,n)=>n>32?O(t,e,n):m(t,e,n),T=(t,e,n)=>n>32?I(t,e,n):B(t,e,n);function Q(t,e=24){let n=new Uint32Array(10);for(let r=24-e;r<24;r++){for(let o=0;o<10;o++)n[o]=t[o]^t[o+10]^t[o+20]^t[o+30]^t[o+40];for(let o=0;o<10;o+=2){let c=(o+8)%10,p=(o+2)%10,l=n[p],u=n[p+1],N=S(l,u,1)^n[c],C=T(l,u,1)^n[c+1];for(let a=0;a<50;a+=10)t[o+a]^=N,t[o+a+1]^=C}let s=t[2],i=t[3];for(let o=0;o<24;o++){let c=j[o],p=S(s,i,c),l=T(s,i,c),u=F[o];s=t[u],i=t[u+1],t[u]=p,t[u+1]=l}for(let o=0;o<50;o+=10){for(let c=0;c<10;c++)n[c]=t[o+c];for(let c=0;c<10;c++)t[o+c]^=~n[(c+2)%10]&n[(c+4)%10]}t[0]^=J[r],t[1]^=K[r]}n.fill(0)}var y=class t extends x{constructor(e,n,r,s=!1,i=24){if(super(),this.blockLen=e,this.suffix=n,this.outputLen=r,this.enableXOF=s,this.rounds=i,this.pos=0,this.posOut=0,this.finished=!1,this.destroyed=!1,g(r),0>=this.blockLen||this.blockLen>=200)throw new Error("Sha3 supports only keccak-f1600 function");this.state=new Uint8Array(200),this.state32=E(this.state)}keccak(){Q(this.state32,this.rounds),this.posOut=0,this.pos=0}update(e){k(this);let{blockLen:n,state:r}=this;e=w(e);let s=e.length;for(let i=0;i<s;){let o=Math.min(n-this.pos,s-i);for(let c=0;c<o;c++)r[this.pos++]^=e[i++];this.pos===n&&this.keccak()}return this}finish(){if(this.finished)return;this.finished=!0;let{state:e,suffix:n,pos:r,blockLen:s}=this;e[r]^=n,n&128&&r===s-1&&this.keccak(),e[s-1]^=128,this.keccak()}writeInto(e){k(this,!1),b(e),this.finish();let n=this.state,{blockLen:r}=this;for(let s=0,i=e.length;s<i;){this.posOut>=r&&this.keccak();let o=Math.min(r-this.posOut,i-s);e.set(n.subarray(this.posOut,this.posOut+o),s),this.posOut+=o,s+=o}return e}xofInto(e){if(!this.enableXOF)throw new Error("XOF is not possible for this instance");return this.writeInto(e)}xof(e){return g(e),this.xofInto(new Uint8Array(e))}digestInto(e){if(L(e,this),this.finished)throw new Error("digest() was already called");return this.writeInto(e),this.destroy(),e}digest(){return this.digestInto(new Uint8Array(this.outputLen))}destroy(){this.destroyed=!0,this.state.fill(0)}_cloneInto(e){let{blockLen:n,suffix:r,outputLen:s,rounds:i,enableXOF:o}=this;return e||(e=new t(n,r,s,o,i)),e.state32.set(this.state32),e.pos=this.pos,e.posOut=this.posOut,e.finished=this.finished,e.rounds=i,e.suffix=r,e.outputLen=s,e.enableXOF=o,e.destroyed=this.destroyed,e}},f=(t,e,n)=>U(()=>new y(e,t,n)),it=f(6,144,224/8),ct=f(6,136,256/8),ft=f(6,104,384/8),ut=f(6,72,512/8),ht=f(1,144,224/8),Y=f(1,136,256/8),pt=f(1,104,384/8),lt=f(1,72,512/8),$=(t,e,n)=>H((r={})=>new y(e,t,r.dkLen===void 0?n:r.dkLen,!0)),at=$(31,168,128/8),dt=$(31,136,256/8);export{Y as keccak256};
+/*! Bundled license information:
+
+@noble/hashes/esm/utils.js:
+ (*! noble-hashes - MIT License (c) 2022 Paul Miller (paulmillr.com) *)
+*/
git.ardis.lu / event-hashes / commitdiff
