[Fix] Connection issues in example-usage & wasm

.gitignore

@@ -2,3 +2,4 @@
 **Cargo.lock
 *.pem
 *.key
+example-usage/dev-cert/

example-usage/.gitignore

@@ -3,5 +3,9 @@ host_keys.json
 host_sig_pk.bin
 host_sig_pq_pk.bin
 host_enc_kem_pk.bin
+host_public_key_bundle.hex
 clients.json
 web-client/node_modules
+dev-cert/
+web-client/public/host_public_key_bundle.hex
+web-client/public/mtp_dev_cert_hash.txt

example-usage/server/Cargo.toml

@@ -14,3 +14,4 @@ tokio = { version = "1", features = ["full"] }
 serde_json = { version = "1" }
 hex = "0.4"
 serde_core = "1.0.228"
+base64 = "0.22"

example-usage/server/src/keys.rs

@@ -27,6 +27,17 @@ pub fn load_or_generate_host_keys(path: &str) -> Result<(u64, Keyring), Box<dyn
 }
 
 pub fn export_host_public_keys(host_keyring: &Keyring) -> Result<(), Box<dyn std::error::Error>> {
+    let public_key_bundle_hex = hex::encode(host_keyring.public_key_bundle().as_bytes());
+
+    fs::write(
+        "host_public_key_bundle.hex",
+        &public_key_bundle_hex,
+    )?;
+    fs::create_dir_all("web-client/public")?;
+    fs::write(
+        "web-client/public/host_public_key_bundle.hex",
+        &public_key_bundle_hex,
+    )?;
     fs::write(
         "host_enc_kem_pk.bin",
         host_keyring.kem_public_key.as_bytes(),

example-usage/server/src/main.rs

@@ -5,10 +5,34 @@ mod tls;
 
 use mtp::host::{HostConfig, MTPHost};
 use mtp::type_map::TypeMap;
+use std::path::Path;
+
+fn dev_cert_paths() -> (String, String) {
+    let cert = std::env::var("MTP_DEV_CERT").unwrap_or_else(|_| {
+        if Path::new("example-usage/dev-cert/cert.pem").exists() {
+            "example-usage/dev-cert/cert.pem".to_string()
+        } else {
+            "dev-cert/cert.pem".to_string()
+        }
+    });
+    let key = std::env::var("MTP_DEV_KEY").unwrap_or_else(|_| {
+        if Path::new("example-usage/dev-cert/key.pem").exists() {
+            "example-usage/dev-cert/key.pem".to_string()
+        } else {
+            "dev-cert/key.pem".to_string()
+        }
+    });
+    (cert, key)
+}
 
 #[tokio::main]
 async fn main() -> Result<(), Box<dyn std::error::Error>> {
-    let (cert_pem, key_pem) = tls::load_or_generate_tls("server.pem", "server.key")?;
+    let (cert_path, key_path) = dev_cert_paths();
+    let (cert_pem, key_pem) = tls::load_or_generate_tls(&cert_path, &key_path)?;
+    let cert_hash = tls::certificate_sha256_hex(&cert_pem)?;
+    tls::export_webtransport_cert_hash(&cert_hash)?;
+    println!("WebTransport certificate sha256: {cert_hash}");
+
     let (host_id, host_keyring) = keys::load_or_generate_host_keys("host_keys.json")?;
     keys::export_host_public_keys(&host_keyring)?;
 

example-usage/server/src/tls.rs

@@ -1,4 +1,7 @@
 use std::fs;
+use std::path::Path;
+
+use base64::Engine;
 
 pub fn load_or_generate_tls(
     cert_path: &str,
@@ -10,6 +13,12 @@ pub fn load_or_generate_tls(
     }
 
     println!("Generating self-signed TLS certificate ...");
+    if let Some(parent) = Path::new(cert_path).parent() {
+        fs::create_dir_all(parent)?;
+    }
+    if let Some(parent) = Path::new(key_path).parent() {
+        fs::create_dir_all(parent)?;
+    }
     let key_pair = rcgen::KeyPair::generate()?;
     let params = rcgen::CertificateParams::new(vec!["localhost".into(), "127.0.0.1".into()])?;
     let cert = params.self_signed(&key_pair)?;
@@ -23,3 +32,39 @@ pub fn load_or_generate_tls(
 
     Ok((cert_str.into_bytes(), key_str.into_bytes()))
 }
+
+pub fn certificate_sha256_hex(cert: &[u8]) -> Result<String, Box<dyn std::error::Error>> {
+    let der = if cert.starts_with(b"-----BEGIN CERTIFICATE-----") {
+        let pem = std::str::from_utf8(cert)?;
+        let base64 = pem
+            .lines()
+            .filter(|line| !line.starts_with("-----"))
+            .collect::<String>();
+        base64::engine::general_purpose::STANDARD.decode(base64)?
+    } else {
+        cert.to_vec()
+    };
+
+    Ok(hex::encode(mtp::crypto::sha256(&der)))
+}
+
+pub fn export_webtransport_cert_hash(hash: &str) -> Result<(), Box<dyn std::error::Error>> {
+    let public_dir = if Path::new("web-client").exists() {
+        Path::new("web-client/public")
+    } else {
+        Path::new("example-usage/web-client/public")
+    };
+    fs::create_dir_all(public_dir)?;
+    fs::write(public_dir.join("mtp_dev_cert_hash.txt"), hash)?;
+
+    let dev_cert_dir = if Path::new("dev-cert").exists() {
+        Path::new("dev-cert")
+    } else {
+        Path::new("example-usage/dev-cert")
+    };
+    if dev_cert_dir.exists() {
+        fs::write(dev_cert_dir.join("sha256.txt"), hash)?;
+    }
+
+    Ok(())
+}

example-usage/web-client/index.html

@@ -5,8 +5,11 @@
   <meta name="viewport" content="width=device-width, initial-scale=1.0" />
   <title>MTP Web Client</title>
   <style>
-    body { font-family: monospace; background: #111; color: #0f0; padding: 2rem; }
-    #status { white-space: pre-wrap; }
+    body { background: #111; color: #eee; font-family: "Public Sans", sans-serif; }
+    label, input, textarea { display: block; margin-bottom: 0.5rem; }
+    input, textarea, button { font-family: "Public Sans", sans-serif; }
+    input, textarea { background: #222; color: #eee; }
+    #status, #key-status { white-space: pre-wrap; }
     .state { color: #ff0; }
     .received { color: #0ff; }
     .error { color: #f00; }
@@ -14,7 +17,23 @@
 </head>
 <body>
   <h1>MTP WebTransport Client</h1>
-  <div id="status">Initializing...</div>
+  <label for="server-url">Server URL</label>
+  <input id="server-url" value="https://127.0.0.1:8080" />
+
+  <label for="host-public-key">Host public key bundle hex</label>
+  <textarea id="host-public-key" placeholder="Paste PublicKeyBundle bytes as hex"></textarea>
+
+  <label for="client-public-key">Generated client public key bundle hex</label>
+  <textarea id="client-public-key" readonly></textarea>
+
+  <div>
+    <button id="generate-keypair" type="button">Generate keypair</button>
+    <button id="connect" type="button" disabled>Connect</button>
+    <button id="clear-keys" type="button">Clear saved keys</button>
+  </div>
+
+  <div id="key-status">Initializing...</div>
+  <div id="status"></div>
   <script type="module" src="/src/main.ts"></script>
 </body>
 </html>

example-usage/web-client/src/main.ts

@@ -2,15 +2,33 @@ import init, {
   WasmClient,
   ConnectionConfig,
   ConnectionState,
-  WasmEd25519Signer,
+  WasmKeyring,
   ed25519_generate,
   keyring_from_ed25519,
   build_demo_message,
 } from "mtp-wasm";
 
 const STATUS = document.getElementById("status")!;
+const KEY_STATUS = document.getElementById("key-status")!;
+const SERVER_URL = document.getElementById("server-url") as HTMLInputElement;
+const HOST_PUBLIC_KEY = document.getElementById("host-public-key") as HTMLTextAreaElement;
+const CLIENT_PUBLIC_KEY = document.getElementById("client-public-key") as HTMLTextAreaElement;
+const GENERATE_KEYPAIR = document.getElementById("generate-keypair") as HTMLButtonElement;
+const CONNECT = document.getElementById("connect") as HTMLButtonElement;
+const CLEAR_KEYS = document.getElementById("clear-keys") as HTMLButtonElement;
+
 const STORAGE_KEY = "mtp-web-client-keys";
 
+type SavedKeys = {
+  clientId: string | null;
+  keyring: number[];
+  hostPublicKey?: number[];
+};
+
+let keyringBytes: Uint8Array | null = null;
+let clientId: bigint | null = null;
+let devCertHash = "";
+
 function log(msg: string, cls = "") {
   const line = document.createElement("div");
   line.textContent = msg;
@@ -18,28 +36,101 @@ function log(msg: string, cls = "") {
   STATUS.appendChild(line);
 }
 
-function saveKeys(clientId: bigint, keyringBytes: Uint8Array) {
-  const data = {
-    clientId: clientId.toString(),
+function setKeyStatus(msg: string) {
+  KEY_STATUS.textContent = msg;
+}
+
+function bytesToHex(bytes: Uint8Array): string {
+  return Array.from(bytes, (byte) => byte.toString(16).padStart(2, "0")).join("");
+}
+
+function hexToBytes(value: string): Uint8Array {
+  const hex = value.replace(/[^0-9a-fA-F]/g, "");
+  if (hex.length === 0) throw new Error("host public key is required");
+  if (hex.length % 2 !== 0) throw new Error("host public key hex has an odd length");
+
+  const bytes = new Uint8Array(hex.length / 2);
+  for (let i = 0; i < bytes.length; i += 1) {
+    bytes[i] = Number.parseInt(hex.slice(i * 2, i * 2 + 2), 16);
+  }
+  return bytes;
+}
+
+function saveKeys() {
+  if (!keyringBytes) return;
+
+  let hostPublicKey: number[] | undefined;
+  try {
+    hostPublicKey = Array.from(hexToBytes(HOST_PUBLIC_KEY.value));
+  } catch {
+    hostPublicKey = undefined;
+  }
+
+  const data: SavedKeys = {
+    clientId: clientId?.toString() ?? null,
     keyring: Array.from(keyringBytes),
+    hostPublicKey,
   };
   localStorage.setItem(STORAGE_KEY, JSON.stringify(data));
 }
 
-function loadKeys(): { clientId: bigint; keyringBytes: Uint8Array } | null {
+function loadKeys() {
   const raw = localStorage.getItem(STORAGE_KEY);
-  if (!raw) return null;
-  const data = JSON.parse(raw);
-  return {
-    clientId: BigInt(data.clientId),
-    keyringBytes: new Uint8Array(data.keyring),
-  };
+  if (!raw) {
+    setKeyStatus("No client keypair generated yet.");
+    return;
+  }
+
+  const data = JSON.parse(raw) as SavedKeys;
+  keyringBytes = new Uint8Array(data.keyring);
+  clientId = data.clientId ? BigInt(data.clientId) : null;
+  CLIENT_PUBLIC_KEY.value = publicKeyHexFromKeyring(keyringBytes);
+  if (data.hostPublicKey) {
+    HOST_PUBLIC_KEY.value = bytesToHex(new Uint8Array(data.hostPublicKey));
+  }
+
+  setKeyStatus(
+    clientId
+      ? `Loaded saved client keypair for client ${clientId}.`
+      : "Loaded generated client keypair. Not registered yet.",
+  );
+}
+
+async function loadHostPublicKey() {
+  try {
+    const response = await fetch("/host_public_key_bundle.hex", { cache: "no-store" });
+    if (!response.ok) return;
+
+    const hostPublicKey = (await response.text()).trim();
+    if (!hostPublicKey) return;
+
+    HOST_PUBLIC_KEY.value = hostPublicKey;
+    saveKeys();
+    log("Loaded host public key bundle from public file.");
+  } catch {
+    // Manual paste still works when the server has not exported the file yet.
+  }
+}
+
+async function loadDevCertHash() {
+  try {
+    const response = await fetch("/mtp_dev_cert_hash.txt", { cache: "no-store" });
+    if (!response.ok) return;
+
+    devCertHash = (await response.text()).trim();
+    if (devCertHash) {
+      log(`Loaded WebTransport certificate hash: ${devCertHash}`);
+    }
+  } catch {
+    devCertHash = "";
+  }
 }
 
 async function initWasm() {
   log("Loading WASM module...");
   await init();
   log(`WASM loaded. WebTransport supported: ${WasmClient.is_supported()}`);
+  CONNECT.disabled = !WasmClient.is_supported();
 }
 
 function createClient(): WasmClient {
@@ -65,55 +156,107 @@ function generateKeyringBytes(): Uint8Array {
   return keyring_from_ed25519(sk, pk);
 }
 
-async function run() {
-  await initWasm();
+function publicKeyHexFromKeyring(bytes: Uint8Array): string {
+  const keyring = WasmKeyring.from_bytes(bytes);
+  const publicBundle = keyring.public_key_bundle();
+  const publicHex = bytesToHex(publicBundle.to_bytes());
+  publicBundle.free();
+  keyring.free();
+  return publicHex;
+}
+
+async function connect() {
+  STATUS.textContent = "";
 
   if (!WasmClient.is_supported()) {
     log("WebTransport is not supported in this browser.", "error");
     return;
   }
-
-  const serverUrl = "https://127.0.0.1:8080";
-  const saved = loadKeys();
-
-  const client = createClient();
-  const config = new ConnectionConfig(serverUrl);
-
-  let clientId: bigint;
-  let keyringBytes: Uint8Array;
-
-  if (saved) {
-    log(`Found saved client keys (ID: ${saved.clientId})`);
-    const hostPk = new Uint8Array(0);
-    clientId = await client.auth_connect(
-      config,
-      hostPk,
-      saved.keyringBytes,
-      saved.clientId,
-    );
-    log(`Authenticated as client ${clientId}`);
-    keyringBytes = saved.keyringBytes;
-  } else {
-    log("No saved keys: registering new client...");
-    const hostPk = new Uint8Array(0);
-    keyringBytes = generateKeyringBytes();
-    clientId = await client.auth_register(config, hostPk, keyringBytes);
-    log(`Registered with ID: ${clientId}`);
-    saveKeys(clientId, keyringBytes);
-    log("Saved client keys to localStorage");
+  if (!keyringBytes) {
+    log("Generate a client keypair first.", "error");
+    return;
   }
 
-  config.free();
+  const hostPk = hexToBytes(HOST_PUBLIC_KEY.value);
+  await loadDevCertHash();
 
-  log("\nSending demo message...");
-  const frame = build_demo_message(clientId, keyringBytes);
-  await client.send(frame);
-  log(`Sent ${frame.length} bytes`);
+  const client = createClient();
+  const config = new ConnectionConfig(SERVER_URL.value.trim());
+  if (devCertHash) {
+    log(`Pinning WebTransport certificate hash: sha-256:${devCertHash}`);
+    config.server_certificate_hashes = [`sha-256:${devCertHash}`];
+  } else {
+    log("No WebTransport certificate hash loaded; relying on browser trust store.", "state");
+  }
 
-  log("\nClient running. Waiting for incoming messages...");
+  try {
+    let activeClientId: bigint;
+    if (clientId !== null) {
+      log(`Using saved client ID ${clientId}...`);
+      activeClientId = await client.auth_connect(
+        config,
+        hostPk,
+        keyringBytes,
+        clientId,
+      );
+      log(`Authenticated as client ${activeClientId}`);
+    } else {
+      log("Registering generated client keypair...");
+      activeClientId = await client.auth_register(config, hostPk, keyringBytes);
+      clientId = activeClientId;
+      saveKeys();
+      log(`Registered with ID: ${activeClientId}`);
+    }
+
+    log("\nSending demo message...");
+    const frame = build_demo_message(activeClientId, keyringBytes);
+    await client.send(frame);
+    log(`Sent ${frame.length} bytes`);
+
+    log("\nClient running. Waiting for incoming messages...");
+  } finally {
+    config.free();
+  }
 }
 
-run().catch((e) => {
-  log(`Fatal error: ${e}`, "error");
-  console.error(e);
+GENERATE_KEYPAIR.addEventListener("click", () => {
+  try {
+    keyringBytes = generateKeyringBytes();
+    clientId = null;
+    saveKeys();
+    CLIENT_PUBLIC_KEY.value = publicKeyHexFromKeyring(keyringBytes);
+    setKeyStatus("Generated client keypair. Not registered yet.");
+    log("Generated and saved a new client keypair.");
+  } catch (e) {
+    log(`Key generation failed: ${e}`, "error");
+    console.error(e);
+  }
 });
+
+CONNECT.addEventListener("click", () => {
+  connect().catch((e) => {
+    log(`Fatal error: ${e}`, "error");
+    console.error(e);
+  });
+});
+
+CLEAR_KEYS.addEventListener("click", () => {
+  keyringBytes = null;
+  clientId = null;
+  CLIENT_PUBLIC_KEY.value = "";
+  localStorage.removeItem(STORAGE_KEY);
+  setKeyStatus("No client keypair generated yet.");
+  log("Cleared saved client keys.");
+});
+
+HOST_PUBLIC_KEY.addEventListener("change", saveKeys);
+
+initWasm()
+  .then(() => {
+    loadKeys();
+    return Promise.all([loadHostPublicKey(), loadDevCertHash()]);
+  })
+  .catch((e) => {
+    log(`Fatal error: ${e}`, "error");
+    console.error(e);
+  });

example-usage/web-client/vite.config.ts

@@ -1,6 +1,13 @@
 import { defineConfig } from 'vite';
+import fs from 'fs';
 import path from 'path';
 
+const devCertDir = path.resolve(__dirname, '../dev-cert');
+const certPath = process.env.MTP_DEV_CERT ?? path.join(devCertDir, 'cert.pem');
+const keyPath = process.env.MTP_DEV_KEY ?? path.join(devCertDir, 'key.pem');
+
+const hasDevCert = fs.existsSync(certPath) && fs.existsSync(keyPath);
+
 export default defineConfig({
   resolve: {
     alias: {
@@ -8,6 +15,12 @@ export default defineConfig({
     },
   },
   server: {
+    https: hasDevCert
+      ? {
+          cert: fs.readFileSync(certPath),
+          key: fs.readFileSync(keyPath),
+        }
+      : undefined,
     fs: {
       allow: ['.', path.resolve(__dirname, '../../wasm/pkg')],
     },

flake.nix

@@ -43,12 +43,50 @@
           MTP_TYPE_MAPS = "${toString ./example-usage/type-maps.yaml}";
 
           shellHook = ''
+            cert_dir="$PWD/example-usage/dev-cert"
+            public_dir="$PWD/example-usage/web-client/public"
+            cert_key="$cert_dir/key.pem"
+            cert_pem="$cert_dir/cert.pem"
+            cert_hash="$cert_dir/sha256.txt"
+
+            mkdir -p "$cert_dir"
+            mkdir -p "$public_dir"
+
+            if [ ! -f "$cert_key" ] || [ ! -f "$cert_pem" ]; then
+              openssl ecparam -name prime256v1 -genkey -noout -out "$cert_key"
+              openssl req -new -x509 \
+                -sha256 \
+                -key "$cert_key" \
+                -out "$cert_pem" \
+                -days 13 \
+                -subj "/CN=localhost" \
+                -addext "subjectAltName=DNS:localhost,IP:127.0.0.1" \
+                -addext "basicConstraints=critical,CA:FALSE" \
+                -addext "keyUsage=critical,digitalSignature" \
+                -addext "extendedKeyUsage=serverAuth"
+              cert_status="generated"
+            else
+              cert_status="cached"
+            fi
+
+            openssl x509 -in "$cert_pem" -outform der \
+              | openssl dgst -sha256 -binary \
+              | od -An -tx1 -v \
+              | tr -d ' \n' > "$cert_hash"
+            cp "$cert_hash" "$public_dir/mtp_dev_cert_hash.txt"
+
+            export MTP_DEV_CERT="$cert_pem"
+            export MTP_DEV_KEY="$cert_key"
+            export MTP_DEV_CERT_HASH="$(cat "$cert_hash")"
+
             echo "MTP dev shell"
             echo "  rustc  : $(rustc --version)"
             echo "  cargo  : $(cargo --version)"
             echo "  wasm-pack : $(wasm-pack --version 2>/dev/null || echo 'not found')"
             echo "  targets: $(rustc --print target-list | grep wasm32 | tr '\n' ' ')"
             echo "  MTP_TYPE_MAPS = $MTP_TYPE_MAPS"
+            echo "  dev cert: $MTP_DEV_CERT ($cert_status)"
+            echo "  cert sha256: $MTP_DEV_CERT_HASH"
           '';
         };
 

wasm/src/client.rs

@@ -124,12 +124,14 @@ impl WasmClient {
     pub async fn auth_connect(
         &mut self,
         config: &ConnectionConfig,
-        _host_public_key_bytes: &[u8],
+        host_public_key_bytes: &[u8],
         keyring_bytes: &[u8],
         client_id: u64,
     ) -> Result<u64, JsValue> {
         self.set_state(ConnectionState::Connecting);
 
+        let _host_pk = mtp_crypto::PublicKeyBundle::from_bytes(host_public_key_bytes)
+            .map_err(|e| js_error(&format!("invalid host public key: {}", e)))?;
         let keyring = mtp_crypto::Keyring::from_bytes(keyring_bytes)
             .map_err(|e| js_error(&format!("invalid keyring: {}", e)))?;
 

wasm/src/transport.rs

@@ -200,7 +200,7 @@ impl WasmTransport {
 
             if buffer.len() >= 4 {
                 let frame_len =
-                    u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+                    u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
                 if 4 + frame_len <= buffer.len() {
                     return Ok(buffer[4..4 + frame_len].to_vec());
                 }
@@ -303,7 +303,7 @@ impl WasmTransport {
             // Extract all complete frames from the buffer
             while buffer.len() >= 4 {
                 let frame_len =
-                    u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+                    u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
                 if 4 + frame_len > buffer.len() {
                     break;
                 }
@@ -317,7 +317,7 @@ impl WasmTransport {
         // Process any remaining complete frames after stream closes
         while buffer.len() >= 4 {
             let frame_len =
-                u32::from_le_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
+                u32::from_be_bytes([buffer[0], buffer[1], buffer[2], buffer[3]]) as usize;
             if 4 + frame_len > buffer.len() {
                 break;
             }