-WIP on Bearer token

src/Authorize/Bearer/JsonWebTokenValidate.php

@@ -0,0 +1,56 @@
+<?php
+
+namespace Ulmus\User\Authorize\Bearer;
+
+abstract class JsonWebTokenValidate
+{
+    public static function validateHeaderAlgorithm(array $header) : void
+    {
+        if (! array_key_exists('alg', $header)) {
+            throw new JsonWebTokenDecodingError("Your header data is missing a valid algorithm (alg).");
+        }
+
+        if ( ! JsonWebTokenAlgorithmEnum::exists($header['alg']) ) {
+            throw new JsonWebTokenDecodingError(
+                sprintf("Given algorithm '%s' is not supported. Please try with one of the above : %s", $header['alg'], implode(', ', JsonWebTokenAlgorithmEnum::list()))
+            );
+        }
+    }
+
+    public static function validateHeaderType(array $header) : void
+    {
+        if ( array_key_exists('typ', $header) && ! JsonWebTokenTypeEnum::exists($header['typ']) ) {
+            throw new JsonWebTokenDecodingError(
+                sprintf("Given type '%s' is not supported. Please try with one of the above : %s", $header['typ'], implode(', ', JsonWebTokenTypeEnum::list()))
+            );
+        }
+    }
+
+    public static function validateSignature(string $alg, string $secret, string $encodedHeader, string $encodedPayload, string $encodedSignature) : void
+    {
+        $algorithm = JsonWebTokenAlgorithmEnum::fromString($alg);
+
+        static::validateAlgorithm($algorithm);
+
+        $decodedSignature = JsonWebTokenDecoder::base64url_decode($encodedSignature);
+
+        list($algo, $method, ) = $algorithm->phpAlgoMethods();
+
+        switch($method) {
+            case 'hash_hmac':
+                $compare = hash_hmac($algo, sprintf("%s.%s", $encodedHeader, $encodedPayload), $secret, true);
+            break;
+        }
+
+        if ( ($compare ?? null) !== $decodedSignature) {
+            throw new JsonWebTokenDecodingError(
+                sprintf("Given signature (%s) do not match computed signature (%s)", $encodedSignature, JsonWebTokenEncoder::base64url_encode($compare))
+            );
+        }
+    }
+
+    public static function validateAlgorithm(JsonWebTokenAlgorithmEnum $algorithm) : void
+    {
+        $algorithm->assessOperability();
+    }
+}