kudos to Johann

contentScript.js

@@ -1,3 +1,178 @@
+async function generateKey() {
+    return await crypto.subtle.generateKey(
+        {
+            name: "ECDSA",
+            namedCurve: "P-256"
+        },
+        true,   // Whether the key is extractable (i.e., can be used outside the Crypto API)
+        ["sign", "verify"] // Can be used for signing and verification
+    );
+}
+
+// Convert the data (e.g., event hash) to an ArrayBuffer
+function str2ab(str) {
+    const buf = new ArrayBuffer(str.length * 2); // 2 bytes for each char
+    const bufView = new Uint16Array(buf);
+    for (let i = 0, strLen = str.length; i < strLen; i++) {
+        bufView[i] = str.charCodeAt(i);
+    }
+    return buf;
+}
+
+// Sign the event hash
+async function signEventHash(privateKey, eventHash) {
+    const encodedEventHash = str2ab(eventHash);
+    const signature = await crypto.subtle.sign(
+        {
+            name: "ECDSA",
+            hash: { name: "SHA-256" } // Choose the hash algorithm you want to use
+        },
+        privateKey,
+        encodedEventHash // The data you want to sign
+    );
+    return new Uint8Array(signature);
+}
+
+function byteArrayTo64BytesHex(byteArray) {
+    // Convert the byte array to a hex string
+    let hex = Array.from(byteArray, function(byte) {
+        return ('0' + (byte & 0xFF).toString(16)).slice(-2);
+    }).join('');
+
+    // Ensure the hex string is exactly 128 characters long (64 bytes)
+    if (hex.length > 128) {
+        hex = hex.slice(0, 128); // Truncate if it's too long
+    } else {
+        hex = hex.padEnd(128, '0'); // Pad with zeros if it's too short
+    }
+
+    return hex;
+}
+
+function stringTo64BytesHex(str) {
+    // Convert the string to a hexadecimal string
+    let hex = Array.from(str, function(c) {
+        return c.charCodeAt(0).toString(16).padStart(2, '0');
+    }).join('');
+
+    // Ensure the hex string is exactly 128 characters long (64 bytes)
+    if (hex.length > 128) {
+        hex = hex.slice(0, 128); // Truncate if it's too long
+    } else {
+        hex = hex.padEnd(128, '0'); // Pad with zeros if it's too short
+    }
+
+    return hex;
+}
+
+function stringTo32BytesHex(str) {
+    // Convert the string to a hexadecimal string
+    let hex = Array.from(str, function(c) {
+        return c.charCodeAt(0).toString(16).padStart(2, '0');
+    }).join('');
+
+    // Ensure the hex string is exactly 64 characters long (32 bytes)
+    if (hex.length > 64) {
+        hex = hex.slice(0, 64); // Truncate if it's too long
+    } else {
+        hex = hex.padEnd(64, '0'); // Pad with zeros if it's too short
+    }
+
+    return hex;
+}
+
+const relayUrl = "wss://relay.sc24.steffen-roertgen.de"; 
+const socket = new WebSocket(relayUrl);
+const publicKey = 'npub1r30l8j4vmppvq8w23umcyvd3vct4zmfpfkn4c7h2h057rmlfcrmq9xt9ma';
+
+async function signEvent(event, privateKey) {
+    const eventHash = await hashEvent(event); // You need to create a hash of the event
+    const signature = await signEventHash(privateKey, eventHash);
+    event.sig = byteArrayTo64BytesHex(signature);
+    event.id = stringTo32BytesHex(eventHash); // The event ID is the hash of the event
+}
+
+// Example function to hash an event
+async function hashEvent(event) {
+    const eventString = JSON.stringify([event.pubkey, event.created_at, event.kind, event.tags, event.content]);
+    const encoder = new TextEncoder();
+    const data = encoder.encode(eventString);
+    const hashBuffer = await crypto.subtle.digest('SHA-256', data);
+    const hashArray = Array.from(new Uint8Array(hashBuffer));
+    return hashArray.map(byte => byte.toString(16).padStart(2, '0')).join('');
+}
+
+// Send the event to the relay
+async function sendEventToRelay(event) {
+    const privateKey = await generateKey(); 
+    await signEvent(event, privateKey.privateKey);
+
+    socket.send(JSON.stringify(["EVENT", event]));
+    console.log("Event sent to the relay:", event);
+
+    socket.addEventListener('message', function (message) {
+        console.log("Received message from relay:", message.data);
+    });
+
+    socket.addEventListener('error', function (error) {
+        console.error("WebSocket error:", error);
+    });
+
+    socket.addEventListener('close', function () {
+        console.log("WebSocket connection closed");
+    });
+}
+
+function findLDJSONScripts() {
+    const scripts = document.querySelectorAll('script[type="application/ld+json"]');
+    const jsonData = [];
+
+    scripts.forEach(script => {
+        try {
+            const json = JSON.parse(script.textContent);
+            jsonData.push(json);
+        } catch (e) {
+            console.error("Error parsing JSON-LD", e);
+        }
+    });
+
+    return jsonData;
+}
+
+window.addEventListener('load', myMain);
+
+function myMain() {
+    console.log("DOM fully loaded and parsed");
+
+    const ldJsonData = findLDJSONScripts();
+
+    if (ldJsonData.length > 0) {
+        console.log(ldJsonData[0])
+        const name1 = ldJsonData[0]['name']
+        const description1 = ldJsonData[0]['description']
+        const dlgtext = `${name1}\n\n${description1}\n\nSend nostr event to relay?`
+        const userConfirmed = confirm(dlgtext);
+
+        if (userConfirmed) {
+            let event = {
+                id: '',           // The ID of the event will be filled in after signing
+                pubkey: stringTo32BytesHex(publicKey),       // Your public key
+                created_at: Math.floor(Date.now() / 1000), // Current timestamp in seconds
+                kind: 1,          // Kind 1 usually refers to a "note" or text event
+                tags: [],         // An array of tags (if any)
+                content: description1, // The message content
+                sig: ''           // Signature will be added after signing
+            };
+            sendEventToRelay(event);
+            alert('data sent to nostr relay')
+
+        }
+
+    }
+}
+
+
+/*
 // contentScript.js
 
 // Function to find and return the content of ld+json scripts
@@ -52,4 +227,4 @@ function myMain() {
 // });
 // Send the extracted JSON-LD data to the popup or render it directly
 //const ldJsonData = findLDJSONScripts();
-
+*/