fapi1-advanced.diff

diff --git a/examples/oauth.ts b/examples/fapi1-advanced.ts
index d55e62d..a8d1d32 100644
--- a/examples/oauth.ts
+++ b/examples/fapi1-advanced.ts
@@ -1,20 +1,39 @@
+import * as undici from 'undici'
 import * as oauth from 'oauth4webapi'
 
 // Prerequisites
 
-let getCurrentUrl!: (...args: any) => URL
+let getAuthorizationResponseOrURLWithFragment!: (...args: any) => URL
 let issuer!: URL // Authorization server's Issuer Identifier URL
 let algorithm!:
   | 'oauth2' /* For .well-known/oauth-authorization-server discovery */
   | 'oidc' /* For .well-known/openid-configuration discovery */
   | undefined /* Defaults to 'oidc' */
 let client_id!: string
-let client_secret!: string
 /**
  * Value used in the authorization request as redirect_uri pre-registered at the Authorization
  * Server.
  */
 let redirect_uri!: string
+/**
+ * A key corresponding to the mtlsClientCertificate.
+ */
+let mtlsClientKey!: string
+/**
+ * A certificate the client has pre-registered at the Authorization Server for use with Mutual-TLS
+ * client authentication method.
+ */
+let mtlsClientCertificate!: string
+/**
+ * A key that is pre-registered at the Authorization Server that the client is supposed to sign its
+ * Request Objects with.
+ */
+let jarPrivateKey!: oauth.CryptoKey
+/**
+ * A key that the client has pre-registered at the Authorization Server for use with Private Key JWT
+ * client authentication method.
+ */
+let clientPrivateKey!: oauth.CryptoKey
 
 // End of prerequisites
 
@@ -23,7 +42,7 @@ const as = await oauth
   .then((response) => oauth.processDiscoveryResponse(issuer, response))
 
 const client: oauth.Client = { client_id }
-const clientAuth = oauth.ClientSecretPost(client_secret)
+const clientAuth = oauth.PrivateKeyJwt(clientPrivateKey)
 
 const code_challenge_method = 'S256'
 /**
@@ -31,38 +50,45 @@ const code_challenge_method = 'S256'
  * the code_verifier and nonce in the end-user session such that it can be recovered as the user
  * gets redirected from the authorization server back to your application.
  */
+const nonce = oauth.generateRandomNonce()
 const code_verifier = oauth.generateRandomCodeVerifier()
 const code_challenge = await oauth.calculatePKCECodeChallenge(code_verifier)
-let state: string | undefined
+
+let request: string
+{
+  const params = new URLSearchParams()
+  params.set('client_id', client.client_id)
+  params.set('code_challenge', code_challenge)
+  params.set('code_challenge_method', code_challenge_method)
+  params.set('redirect_uri', redirect_uri)
+  params.set('response_type', 'code id_token')
+  params.set('scope', 'openid api:read')
+  params.set('nonce', nonce)
+
+  request = await oauth.issueRequestObject(as, client, params, jarPrivateKey)
+}
 
 {
   // redirect user to as.authorization_endpoint
   const authorizationUrl = new URL(as.authorization_endpoint!)
   authorizationUrl.searchParams.set('client_id', client.client_id)
-  authorizationUrl.searchParams.set('redirect_uri', redirect_uri)
-  authorizationUrl.searchParams.set('response_type', 'code')
-  authorizationUrl.searchParams.set('scope', 'api:read')
-  authorizationUrl.searchParams.set('code_challenge', code_challenge)
-  authorizationUrl.searchParams.set('code_challenge_method', code_challenge_method)
-
-  /**
-   * We cannot be sure the AS supports PKCE so we're going to use state too. Use of PKCE is
-   * backwards compatible even if the AS doesn't support it which is why we're using it regardless.
-   */
-  if (as.code_challenge_methods_supported?.includes('S256') !== true) {
-    state = oauth.generateRandomState()
-    authorizationUrl.searchParams.set('state', state)
-  }
+  authorizationUrl.searchParams.set('request', request)
 
   // now redirect the user to authorizationUrl.href
 }
 
 // one eternity later, the user lands back on the redirect_uri
+// Detached Signature ID Token Validation
 // Authorization Code Grant Request & Response
 let access_token: string
 {
-  const currentUrl: URL = getCurrentUrl()
-  const params = oauth.validateAuthResponse(as, client, currentUrl, state)
+  const authorizationResponse: URLSearchParams | URL = getAuthorizationResponseOrURLWithFragment()
+  const params = await oauth.validateDetachedSignatureResponse(
+    as,
+    client,
+    authorizationResponse,
+    nonce,
+  )
 
   const response = await oauth.authorizationCodeGrantRequest(
     as,
@@ -71,9 +97,27 @@ let access_token: string
     params,
     redirect_uri,
     code_verifier,
+    {
+      [oauth.customFetch]: (url, init) => {
+        return undici.fetch(url, {
+          ...init,
+          dispatcher: new undici.Agent({
+            connect: {
+              key: mtlsClientKey,
+              cert: mtlsClientCertificate,
+            },
+          }),
+        })
+      },
+    },
   )
 
-  const result = await oauth.processAuthorizationCodeResponse(as, client, response)
+  const result = await oauth.processAuthorizationCodeResponse(as, client, response, {
+    expectedNonce: nonce,
+  })
+
+  // Check ID Token signature for non-repudiation purposes
+  await oauth.validateApplicationLevelSignature(as, response)
 
   console.log('Access Token Response', result)
   ;({ access_token } = result)
@@ -85,6 +129,21 @@ let access_token: string
     access_token,
     'GET',
     new URL('https://rs.example.com/api'),
+    undefined,
+    undefined,
+    {
+      [oauth.customFetch]: (url, init) => {
+        return undici.fetch(url, {
+          ...init,
+          dispatcher: new undici.Agent({
+            connect: {
+              key: mtlsClientKey,
+              cert: mtlsClientCertificate,
+            },
+          }),
+        })
+      },
+    },
   )
 
   console.log('Protected Resource Response', await response.json())