draft implementation of aggregated claim value parsing

1 files changed, 68 insertions, 14 deletions

diff --git a/snippets/oidc-woocommerce.php b/snippets/oidc-woocommerce.php
index 974869a..2731728 100644
--- a/snippets/oidc-woocommerce.php
+++ b/snippets/oidc-woocommerce.php
@@ -57,6 +57,67 @@ add_filter(
 
 
 /**
+ * Checks if $claimname is in the body or _claim_names of the userinfo.
+ * If yes, returns the claim value. Otherwise, returns false.
+ *
+ * @param string $claimname the claim name to look for
+ * @param array $userinfo the JSON to look in
+ * @param string $claimvalue the source claim value ( from the body of the JWT of the claim source)
+ * @return True if a reference was found
+ */
+function get_claim( $claimname, $userinfo, &$claimvalue ) {
+  if ( ! isset( $token_response ) ) {
+    return False;
+  }
+  /**
+   * If we find a simple claim, return it.
+   */
+  if ( array_keys_exists( $claimname, $token_response ) ) {
+    $claimvalue = $token_response[$claimname];
+    return True;
+  }
+  /**
+   * If there are not aggregated claims, it is over.
+   */
+  if  ( ! array_key_exists( '_claim_names', $token_response ) ||
+        ! array_key_exists( '_claim_sources', $token_response ) ) {
+    return False;
+  }
+  $claim_src_ptr = $token_response['_claim_names'];
+  if ( ! isset( $claim_src_ptr ) ) {
+    return False;
+  }
+  /**
+   * No reference found
+   */
+  if ( ! array_key_exists( $claimname, $claim_src_ptr ) ) {
+    return False;
+  }
+  $src = $claim_src_ptr[$claimname];
+  //Reference found, but no corresponding JWT. This is a malformed userinfo
+  if ( ! array_key_exists( $src, $token_response['_claim_sources']) ) {
+    return False;
+  }
+  //Source claim is not a JWT. Abort.
+  if ( ! array_key_exists( 'JWT',  $src ) ) {
+    return False;
+  }
+  /**
+   * Extract claim from JWT.
+   * FIXME: We probably want to verify the JWT signature/issuer here!
+   */
+  $jwt = $src['JWT'];
+  list ($header, $body, $rest) = split('.', $jwt, 3);
+  $body_decoded = base64_decode ( $body, false );
+  if ( ( isset ( $body_decoded ) ) &&
+    ( array_key_exists( $claimname, $body_decoded ) ) ) {
+    $claimvalue = $body_decoded[$claimname];
+    return True;
+  }
+  return False;
+}
+
+/**
  * Filter to transform (defaults) for the Billing details according to
  * the information obtained from OpenID Connect (OIDC).  WooCommerce
  * already grabs many of the values properly, but there are some fields
@@ -69,28 +130,21 @@ add_filter(
 function filter_checkout_get_value( $in = array() ) {
 	$user = wp_get_current_user();
 	if ( 0 !== $user->ID ) {
-		$token_response = $user->get( 'openid-connect-generic-last-user-claim' );
-		if ( ( isset( $token_response ) ) &&
-			( array_key_exists( 'given_name', $token_response ) ) ) {
-			$given_name                                       = $token_response ['given_name'];
+    $token_response = $user->get( 'openid-connect-generic-last-user-claim' );
+    $src = '';
+    if ( get_claim( 'given_name', $token_response, $given_name ) ) {
 			$in['billing']['billing_first_name']['default']   = $given_name;
 			$in['shipping']['shipping_first_name']['default'] = $given_name;
 		}
-		if ( ( isset( $token_response ) ) &&
-			( array_key_exists( 'family_name', $token_response ) ) ) {
-			$family_name                                     = $token_response ['family_name'];
+		if ( get_claim( 'family_name', $token_response, $family_name ) ) {
 			$in['billing']['billing_last_name']['default']   = $family_name;
 			$in['shipping']['shipping_last_name']['default'] = $family_name;
 		}
-		if ( ( isset( $token_response ) ) &&
-			( array_key_exists( 'phone_number', $token_response ) ) ) {
-			$phone_number                                = $token_response ['phone_number'];
+		if ( get_claim( 'phone_number', $token_response, $phone_number ) ) {
 			$in['billing']['billing_phone']['default']   = $phone_number;
 			$in['shipping']['shipping_phone']['default'] = $phone_number;
-		}
-		if ( ( isset( $token_response ) ) &&
-			( array_key_exists( 'address', $token_response ) ) ) {
-			$address = $token_response ['address'];
+    }
+    if ( get_claim( 'address', $token_response, $address ) ) {
 			if ( array_key_exists( 'postal_code', $address ) ) {
 				$postal_code                                    = $address ['postal_code'];
 				$in['billing']['billing_postcode']['default']   = $postal_code;