Add new classes and methods for session management

src/Socialbox/Classes/CacheLayer/RedisCacheLayer.php

@@ -0,0 +1,118 @@
+<?php
+
+namespace Socialbox\Classes\CacheLayer;
+
+use Redis;
+use RedisException;
+use RuntimeException;
+use Socialbox\Abstracts\CacheLayer;
+
+class RedisCacheLayer extends CacheLayer
+{
+    private Redis $redis;
+
+    /**
+     * Redis cache layer constructor.
+     *
+     * @param string $host The Redis server host.
+     * @param int $port The Redis server port.
+     * @param string|null $password Optional. The Redis server password.
+     */
+    public function __construct(string $host, int $port, ?string $password=null)
+    {
+        if (!extension_loaded('redis'))
+        {
+            throw new RuntimeException('The Redis extension is not loaded in your PHP environment.');
+        }
+
+        $this->redis = new Redis();
+
+        try
+        {
+            $this->redis->connect($host, $port);
+            if ($password !== null)
+            {
+                $this->redis->auth($password);
+            }
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to connect to the Redis server.', 0, $e);
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function set(string $key, mixed $value, int $ttl = 0): bool
+    {
+        try
+        {
+            return $this->redis->set($key, $value, $ttl);
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to set the value in the Redis cache.', 0, $e);
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function get(string $key): mixed
+    {
+        try
+        {
+            return $this->redis->get($key);
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to get the value from the Redis cache.', 0, $e);
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function delete(string $key): bool
+    {
+        try
+        {
+            return $this->redis->del($key) > 0;
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to delete the value from the Redis cache.', 0, $e);
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function exists(string $key): bool
+    {
+        try
+        {
+            return $this->redis->exists($key);
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to check if the key exists in the Redis cache.', 0, $e);
+        }
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function clear(): bool
+    {
+        try
+        {
+            return $this->redis->flushAll();
+        }
+        catch (RedisException $e)
+        {
+            throw new RuntimeException('Failed to clear the Redis cache.', 0, $e);
+        }
+    }
+}

src/Socialbox/Classes/RpcHandler.php

@@ -0,0 +1,196 @@
+<?php
+
+namespace Socialbox\Classes;
+
+use InvalidArgumentException;
+use RuntimeException;
+use Socialbox\Enums\StandardHeaders;
+use Socialbox\Exceptions\CryptographyException;
+use Socialbox\Exceptions\DatabaseOperationException;
+use Socialbox\Exceptions\RpcException;
+use Socialbox\Managers\SessionManager;
+use Socialbox\Objects\ClientRequest;
+use Socialbox\Objects\RpcRequest;
+
+class RpcHandler
+{
+    /**
+     * Gets the incoming ClientRequest object, validates if the request is valid & if a session UUID is provided
+     * checks if the request signature matches the client's provided public key.
+     *
+     * @return ClientRequest The parsed ClientRequest object
+     * @throws RpcException Thrown if the request is invalid
+     */
+    public static function getClientRequest(): ClientRequest
+    {
+        if($_SERVER['REQUEST_METHOD'] !== 'POST')
+        {
+            throw new RpcException('Invalid Request Method, expected POST', 400);
+        }
+
+        try
+        {
+            $headers = Utilities::getRequestHeaders();
+
+            foreach(StandardHeaders::getRequiredHeaders() as $header)
+            {
+                if(!isset($headers[$header]))
+                {
+                    throw new RpcException("Missing required header: $header", 400);
+                }
+
+                // Validate the headers
+                switch(StandardHeaders::tryFrom($header))
+                {
+                    case StandardHeaders::CLIENT_VERSION:
+                        if($headers[$header] !== '1.0')
+                        {
+                            throw new RpcException(sprintf("Unsupported Client Version: %s", $headers[$header]));
+                        }
+                        break;
+
+                    case StandardHeaders::CONTENT_TYPE:
+                        if($headers[$header] !== 'application/json')
+                        {
+                            throw new RpcException("Invalid Content-Type header: Expected application/json", 400);
+                        }
+                        break;
+
+                    case StandardHeaders::FROM_PEER:
+                        if(!Validator::validatePeerAddress($headers[$header]))
+                        {
+                            throw new RpcException("Invalid From-Peer header: " . $headers[$header], 400);
+                        }
+                        break;
+
+                    default:
+                        break;
+                }
+            }
+        }
+        catch(RuntimeException $e)
+        {
+            throw new RpcException("Failed to parse request: " . $e->getMessage(), 400, $e);
+        }
+
+        $clientRequest = new ClientRequest($headers, self::getRpcRequests(), self::getRequestHash());
+
+        // Verify the session & request signature
+        if($clientRequest->getSessionUuid() !== null)
+        {
+            // If no signature is provided, it must be required if the client is providing a Session UUID
+            if($clientRequest->getSignature() === null)
+            {
+                throw new RpcException(sprintf('Unauthorized request, signature required for session based requests', StandardHeaders::SIGNATURE->value), 401);
+            }
+
+            try
+            {
+                if(!SessionManager::sessionExists($clientRequest->getSessionUuid()))
+                {
+                    throw new RpcException('Session UUID not found', 404);
+                }
+
+                $session = SessionManager::getSession($clientRequest->getSessionUuid());
+
+                // Verify the signature of the request
+                if(!Cryptography::verifyContent($clientRequest->getHash(), $clientRequest->getSignature(), $session->getPublicKey()))
+                {
+                    throw new RpcException('Request signature check failed', 400);
+                }
+            }
+            catch(CryptographyException $e)
+            {
+                throw new RpcException('Request signature check failed (Cryptography Error)', 400, $e);
+            }
+            catch(DatabaseOperationException $e)
+            {
+                throw new RpcException('Failed to verify session', 500, $e);
+            }
+        }
+
+        return $clientRequest;
+    }
+
+    /**
+     * Returns the request hash by hashing the request body using SHA256
+     *
+     * @return string Returns the request hash in SHA256 representation
+     */
+    private static function getRequestHash(): string
+    {
+        return hash('sha1', file_get_contents('php://input'));
+    }
+
+    /**
+     * Handles a POST request, returning an array of RpcRequest objects
+     * expects a JSON encoded body with either a single RpcRequest object or an array of RpcRequest objects
+     *
+     * @return RpcRequest[] The parsed RpcRequest objects
+     * @throws RpcException Thrown if the request is invalid
+     */
+    private static function getRpcRequests(): array
+    {
+        try
+        {
+            // Decode the request body
+            $body = Utilities::jsonDecode(file_get_contents('php://input'));
+        }
+        catch(InvalidArgumentException $e)
+        {
+            throw new RpcException("Invalid JSON in request body: " . $e->getMessage(), 400, $e);
+        }
+
+        if(isset($body['method']))
+        {
+            // If it only contains a method, we assume it's a single request
+            return [self::parseRequest($body)];
+        }
+
+        // Otherwise, we assume it's an array of requests
+        return array_map(fn($request) => self::parseRequest($request), $body);
+    }
+
+    /**
+     * Parses the raw request data into an RpcRequest object
+     *
+     * @param array $data The raw request data
+     * @return RpcRequest The parsed RpcRequest object
+     * @throws RpcException If the request is invalid
+     */
+    private static function parseRequest(array $data): RpcRequest
+    {
+        if(!isset($data['method']))
+        {
+            throw new RpcException("Missing 'method' key in request", 400);
+        }
+
+        if(isset($data['id']))
+        {
+            if(!is_string($data['id']))
+            {
+                throw new RpcException("Invalid 'id' key in request: Expected string", 400);
+            }
+
+            if(strlen($data['id']) === 0)
+            {
+                throw new RpcException("Invalid 'id' key in request: Expected non-empty string", 400);
+            }
+
+            if(strlen($data['id']) > 8)
+            {
+                throw new RpcException("Invalid 'id' key in request: Expected string of length <= 8", 400);
+            }
+        }
+
+        if(isset($data['parameters']))
+        {
+            if(!is_array($data['parameters']))
+            {
+                throw new RpcException("Invalid 'parameters' key in request: Expected array", 400);
+            }
+        }
+
+        return new RpcRequest($data['method'], $data['id'] ?? null, $data['parameters'] ?? null);
+    }
+}

src/Socialbox/Classes/StandardMethods/Ping.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Socialbox\Classes\StandardMethods;
+
+use Socialbox\Abstracts\Method;
+use Socialbox\Interfaces\SerializableInterface;
+use Socialbox\Objects\ClientRequest;
+use Socialbox\Objects\RpcRequest;
+
+class Ping extends Method
+{
+    /**
+     * @inheritDoc
+     */
+    public static function execute(ClientRequest $request, RpcRequest $rpcRequest): ?SerializableInterface
+    {
+        return $rpcRequest->produceResponse(true);
+    }
+}

src/Socialbox/Classes/Utilities.php

@@ -0,0 +1,108 @@
+<?php
+
+namespace Socialbox\Classes;
+
+use InvalidArgumentException;
+use RuntimeException;
+
+class Utilities
+{
+    /**
+     * Decodes a JSON string into an associative array, throws an exception if the JSON is invalid
+     *
+     * @param string $json The JSON string to decode
+     * @return array The decoded associative array
+     * @throws InvalidArgumentException If the JSON is invalid
+     */
+    public static function jsonDecode(string $json): array
+    {
+        $decoded = json_decode($json, true);
+
+        if (json_last_error() !== JSON_ERROR_NONE)
+        {
+            throw match (json_last_error())
+            {
+                JSON_ERROR_DEPTH => new InvalidArgumentException("JSON decoding failed: Maximum stack depth exceeded"),
+                JSON_ERROR_STATE_MISMATCH => new InvalidArgumentException("JSON decoding failed: Underflow or the modes mismatch"),
+                JSON_ERROR_CTRL_CHAR => new InvalidArgumentException("JSON decoding failed: Unexpected control character found"),
+                JSON_ERROR_SYNTAX => new InvalidArgumentException("JSON decoding failed: Syntax error, malformed JSON"),
+                JSON_ERROR_UTF8 => new InvalidArgumentException("JSON decoding failed: Malformed UTF-8 characters, possibly incorrectly encoded"),
+                default => new InvalidArgumentException("JSON decoding failed: Unknown error"),
+            };
+        }
+
+        return $decoded;
+    }
+
+    /**
+     * Encodes the given data in Base64.
+     *
+     * @param string $data The data to be encoded.
+     * @return string The Base64 encoded string.
+     * @throws InvalidArgumentException if the encoding fails.
+     */
+    public static function base64encode(string $data): string
+    {
+        $encoded = base64_encode($data);
+
+        if (!$encoded)
+        {
+            throw new InvalidArgumentException('Failed to encode data in Base64');
+        }
+
+        return $encoded;
+    }
+
+    /**
+     * Decodes a Base64 encoded string.
+     *
+     * @param string $data The Base64 encoded data to be decoded.
+     * @return string The decoded data.
+     * @throws InvalidArgumentException If decoding fails.
+     */
+    public static function base64decode(string $data): string
+    {
+        $decoded = base64_decode($data, true);
+
+        if ($decoded === false)
+        {
+            throw new InvalidArgumentException('Failed to decode data from Base64');
+        }
+
+        return $decoded;
+    }
+
+    /**
+     * Returns the request headers as an associative array
+     *
+     * @return array
+     */
+    public static function getRequestHeaders(): array
+    {
+        // Check if function getallheaders() exists
+        if (function_exists('getallheaders'))
+        {
+            $headers = getallheaders();
+        }
+        else
+        {
+            // Fallback for servers where getallheaders() is not available
+            $headers = [];
+            foreach ($_SERVER as $key => $value)
+            {
+                if (str_starts_with($key, 'HTTP_'))
+                {
+                    // Convert header names to the normal HTTP format
+                    $headers[str_replace('_', '-', strtolower(substr($key, 5)))] = $value;
+                }
+            }
+        }
+
+        if($headers === false)
+        {
+            throw new RuntimeException('Failed to get request headers');
+        }
+
+        return $headers;
+    }
+}

src/Socialbox/Classes/Validator.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Socialbox\Classes;
+
+class Validator
+{
+    private const PEER_ADDRESS_PATTERN = "/^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/";
+
+    /**
+     * Validates a peer address
+     *
+     * @param string $address The address to validate.
+     * @return bool True if the address is valid, false otherwise.
+     */
+    public static function validatePeerAddress(string $address): bool
+    {
+        return preg_match(self::PEER_ADDRESS_PATTERN, $address) === 1;
+    }
+}

src/Socialbox/Managers/SessionManager.php

@@ -0,0 +1,182 @@
+<?php
+
+    namespace Socialbox\Managers;
+
+    use DateMalformedStringException;
+    use DateTime;
+    use InvalidArgumentException;
+    use PDO;
+    use PDOException;
+    use Socialbox\Classes\Cryptography;
+    use Socialbox\Classes\Database;
+    use Socialbox\Classes\Utilities;
+    use Socialbox\Enums\SessionState;
+    use Socialbox\Enums\StandardError;
+    use Socialbox\Exceptions\DatabaseOperationException;
+    use Socialbox\Objects\SessionRecord;
+    use Symfony\Component\Uid\Uuid;
+
+    class SessionManager
+    {
+        /**
+         * Creates a new session with the given public key.
+         *
+         * @param string $publicKey The public key to associate with the new session.
+         *
+         * @return string The UUID of the newly created session.
+         *
+         * @throws InvalidArgumentException If the public key is empty or invalid.
+         * @throws DatabaseOperationException If there is an error while creating the session in the database.
+         */
+        public static function createSession(string $publicKey): string
+        {
+            if($publicKey === '')
+            {
+                throw new InvalidArgumentException('The public key cannot be empty', StandardError::RPC_INVALID_ARGUMENTS);
+            }
+
+            if(!Cryptography::validatePublicKey($publicKey))
+            {
+                throw new InvalidArgumentException('The given public key is invalid', StandardError::INVALID_PUBLIC_KEY);
+            }
+
+            $publicKey = Utilities::base64decode($publicKey);
+            $uuid = Uuid::v4()->toRfc4122();
+
+            try
+            {
+                $statement = Database::getConnection()->prepare("INSERT INTO sessions (uuid, public_key) VALUES (?, ?)");
+                $statement->bindParam(1, $uuid);
+                $statement->bindParam(2, $publicKey);
+                $statement->execute();
+            }
+            catch(PDOException $e)
+            {
+                throw new DatabaseOperationException('Failed to create a session on the database', $e);
+            }
+
+            return $uuid;
+        }
+
+        /**
+         * Checks if a session with the given UUID exists in the database.
+         *
+         * @param string $uuid The UUID of the session to check.
+         * @return bool True if the session exists, false otherwise.
+         * @throws DatabaseOperationException If there is an error executing the database query.
+         */
+        public static function sessionExists(string $uuid): bool
+        {
+            try
+            {
+                $statement = Database::getConnection()->prepare("SELECT COUNT(*) FROM sessions WHERE uuid=?");
+                $statement->bindParam(1, $uuid);
+                $statement->execute();
+                $result = $statement->fetchColumn();
+
+                return $result > 0;
+            }
+            catch(PDOException $e)
+            {
+                throw new DatabaseOperationException('Failed to check if the session exists', $e);
+            }
+        }
+
+        /**
+         * Retrieves a session record by its unique identifier.
+         *
+         * @param string $uuid The unique identifier of the session.
+         * @return SessionRecord The session record corresponding to the given UUID.
+         * @throws DatabaseOperationException If the session record cannot be found or if there is an error during retrieval.
+         */
+        public static function getSession(string $uuid): SessionRecord
+        {
+            try
+            {
+                $statement = Database::getConnection()->prepare("SELECT * FROM sessions WHERE uuid=?");
+                $statement->bindParam(1, $uuid);
+                $statement->execute();
+                $data = $statement->fetch(PDO::FETCH_ASSOC);
+
+                if ($data === false)
+                {
+                    throw new DatabaseOperationException(sprintf('Session record %s not found', $uuid));
+                }
+
+                // Convert the timestamp fields to DateTime objects
+                $data['created'] = new DateTime($data['created']);
+                $data['last_request'] = new DateTime($data['last_request']);
+
+                return SessionRecord::fromArray($data);
+            }
+            catch (PDOException | DateMalformedStringException $e)
+            {
+                throw new DatabaseOperationException(sprintf('Failed to retrieve session record %s', $uuid), $e);
+            }
+        }
+
+        /**
+         * Update the authenticated peer associated with the given session UUID.
+         *
+         * @param string $uuid The UUID of the session to update.
+         * @return void
+         */
+        public static function updateAuthenticatedPeer(string $uuid): void
+        {
+            try
+            {
+                $statement = Database::getConnection()->prepare("UPDATE sessions SET authenticated_peer_uuid=? WHERE uuid=?");
+                $statement->bindParam(1, $uuid);
+                $statement->bindParam(2, $uuid);
+                $statement->execute();
+            }
+            catch (PDOException $e)
+            {
+                throw new DatabaseOperationException('Failed to update authenticated peer', $e);
+            }
+        }
+
+        /**
+         * Updates the last request timestamp for a given session by its UUID.
+         *
+         * @param string $uuid The UUID of the session to be updated.
+         * @return void
+         */
+        public static function updateLastRequest(string $uuid): void
+        {
+            try
+            {
+                $formattedTime = (new DateTime('@' . time()))->format('Y-m-d H:i:s');
+                $statement = Database::getConnection()->prepare("UPDATE sessions SET last_request=? WHERE uuid=?");
+                $statement->bindValue(1, $formattedTime, PDO::PARAM_STR);
+                $statement->bindParam(2, $uuid);
+                $statement->execute();
+            }
+            catch (PDOException | DateMalformedStringException $e)
+            {
+                throw new DatabaseOperationException('Failed to update last request', $e);
+            }
+        }
+
+        /**
+         * Updates the state of a session given its UUID.
+         *
+         * @param string $uuid The unique identifier of the session to update.
+         * @param SessionState $state The new state to be set for the session.
+         * @return void No return value.
+         */
+        public static function updateState(string $uuid, SessionState $state): void
+        {
+            try
+            {
+                $state_value = $state->value;
+                $statement = Database::getConnection()->prepare('UPDATE sessions SET state=? WHERE uuid=?');
+                $statement->bindParam(1, $state_value);
+                $statement->bindParam(2, $uuid);
+            }
+            catch(PDOException $e)
+            {
+                throw new DatabaseOperationException('Failed to update session state', $e);
+            }
+        }
+    }

src/Socialbox/Objects/PeerAddress.php

@@ -0,0 +1,96 @@
+<?php
+
+namespace Socialbox\Objects;
+
+use InvalidArgumentException;
+use Socialbox\Classes\Validator;
+use Socialbox\Enums\ReservedUsernames;
+
+class PeerAddress
+{
+    private string $username;
+    private string $domain;
+
+    /**
+     * Constructs a PeerAddress object from a given username and domain
+     *
+     * @param string $username The username of the peer
+     * @param string $domain The domain of the peer
+     */
+    public function __construct(string $username, string $domain)
+    {
+        $this->username = $username;
+        $this->domain = $domain;
+    }
+
+    /**
+     * Constructs a PeerAddress from a full peer address (eg; john@example.com)
+     *
+     * @param string $address The full address of the peer
+     * @return PeerAddress The constructed PeerAddress object
+     */
+    public static function fromAddress(string $address): PeerAddress
+    {
+        if(!Validator::validatePeerAddress($address))
+        {
+            throw new InvalidArgumentException("Invalid peer address: $address");
+        }
+
+        $parts = explode('@', $address);
+        return new PeerAddress($parts[0], $parts[1]);
+    }
+
+    /**
+     * Returns the username of the peer
+     *
+     * @return string
+     */
+    public function getUsername(): string
+    {
+        return $this->username;
+    }
+
+    /**
+     * Returns the domain of the peer
+     *
+     * @return string
+     */
+    public function getDomain(): string
+    {
+        return $this->domain;
+    }
+
+    /**
+     * Returns whether the peer is the host
+     *
+     * @return bool True if the peer is the host, false otherwise
+     */
+    public function isHost(): bool
+    {
+        return $this->username === ReservedUsernames::HOST->value;
+    }
+
+    /**
+     * Returns whether the peer requires authentication, for example, the anonymous user does not require authentication
+     *
+     * @return bool True if authentication is required, false otherwise
+     */
+    public function authenticationRequired(): bool
+    {
+        return match($this->username)
+        {
+            ReservedUsernames::ANONYMOUS->value => false,
+            default => true
+        };
+    }
+
+    /**
+     * Returns the full address of the peer
+     *
+     * @return string The full address of the peer
+     */
+    public function getAddress(): string
+    {
+        return sprintf("%s@%s", $this->username, $this->domain);
+    }
+}

src/Socialbox/Objects/RpcError.php

@@ -2,26 +2,27 @@
 
 namespace Socialbox\Objects;
 
+use Socialbox\Enums\StandardError;
 use Socialbox\Interfaces\SerializableInterface;
 
 class RpcError implements SerializableInterface
 {
     private string $id;
-    private string $error;
-    private int $code;
+    private string $message;
+    private StandardError $code;
 
     /**
      * Constructs the RPC error object.
      *
      * @param string $id The ID of the RPC request
-     * @param string $error The error message
-     * @param int $code The error code
+     * @param StandardError $error The error code
+     * @param string $message The error message
      */
-    public function __construct(string $id, string $error, int $code)
+    public function __construct(string $id, StandardError $error, string $message)
     {
         $this->id = $id;
-        $this->error = $error;
-        $this->code = $code;
+        $this->code = $error;
+        $this->message = $message;
     }
 
     /**
@@ -39,17 +40,17 @@ class RpcError implements SerializableInterface
      *
      * @return string The error message.
      */
-    public function getError(): string
+    public function getMessage(): string
     {
-        return $this->error;
+        return $this->message;
     }
 
     /**
      * Returns the error code.
      *
-     * @return int The error code.
+     * @return StandardError The error code.
      */
-    public function getCode(): int
+    public function getCode(): StandardError
     {
         return $this->code;
     }
@@ -63,8 +64,8 @@ class RpcError implements SerializableInterface
     {
         return [
             'id' => $this->id,
-            'error' => $this->error,
-            'code' => $this->code
+            'error' => $this->message,
+            'code' => $this->code->value
         ];
     }
 
@@ -76,6 +77,13 @@ class RpcError implements SerializableInterface
      */
     public static function fromArray(array $data): RpcError
     {
-        return new RpcError($data['id'], $data['error'], $data['code']);
+        $errorCode = StandardError::tryFrom($data['code']);
+
+        if($errorCode == null)
+        {
+            $errorCode = StandardError::UNKNOWN;
+        }
+
+        return new RpcError($data['id'], $data['error'], $errorCode);
     }
 }

src/Socialbox/Objects/RpcRequest.php

@@ -2,6 +2,11 @@
 
 namespace Socialbox\Objects;
 
+use InvalidArgumentException;
+use ncc\ThirdParty\nikic\PhpParser\Node\Expr\BinaryOp\BooleanOr;
+use Socialbox\Enums\StandardError;
+use Socialbox\Exceptions\RpcException;
+use Socialbox\Exceptions\StandardException;
 use Socialbox\Interfaces\SerializableInterface;
 
 class RpcRequest implements SerializableInterface
@@ -13,13 +18,15 @@ class RpcRequest implements SerializableInterface
     /**
      * Constructs the object from an array of data.
      *
-     * @param array $data The data to construct the object from.
+     * @param string $method The method of the request.
+     * @param string|null $id The ID of the request.
+     * @param array|null $parameters The parameters of the request.
      */
-    public function __construct(array $data)
+    public function __construct(string $method, ?string $id, ?array $parameters)
     {
-        $this->id = $data['id'] ?? null;
-        $this->method = $data['method'];
-        $this->parameters = $data['parameters'] ?? null;
+        $this->method = $method;
+        $this->parameters = $parameters;
+        $this->id = $id;
     }
 
     /**
@@ -45,13 +52,106 @@ class RpcRequest implements SerializableInterface
     /**
      * Returns the parameters of the request.
      *
-     * @return array|null The parameters of the request.
+     * @return array|null The parameters of the request, null if the request is a notification.
      */
     public function getParameters(): ?array
     {
         return $this->parameters;
     }
 
+    /**
+     * Checks if the parameter exists within the RPC request
+     *
+     * @param string $parameter The parameter to check
+     * @return bool True if the parameter exists, False otherwise.
+     */
+    public function containsParameter(string $parameter): bool
+    {
+        return isset($this->parameters[$parameter]);
+    }
+
+    /**
+     * Returns the parameter value from the RPC request
+     *
+     * @param string $parameter The parameter name to get
+     * @return mixed The parameter value, null if the parameter value is null or not found.
+     */
+    public function getParameter(string $parameter): mixed
+    {
+        if(!$this->containsParameter($parameter))
+        {
+            return null;
+        }
+
+        return $this->parameters[$parameter];
+    }
+
+    /**
+     * Produces a response based off the request, null if the request is a notification
+     *
+     * @param mixed|null $result
+     * @return RpcResponse|null
+     */
+    public function produceResponse(mixed $result=null): ?RpcResponse
+    {
+        if($this->id == null)
+        {
+            return null;
+        }
+
+        $valid = false;
+        if(is_array($result))
+        {
+            $valid = true;
+        }
+        elseif($result instanceof SerializableInterface)
+        {
+            $valid = true;
+        }
+        elseif(is_null($result))
+        {
+            $valid = true;
+        }
+
+        if(!$valid)
+        {
+            throw new InvalidArgumentException('The \'$result\' property must either be array, null or SerializableInterface');
+        }
+
+        return new RpcResponse($this->id, $result);
+    }
+
+    /**
+     * Produces an error response based off the request, null if the request is a notification
+     *
+     * @param StandardError $error
+     * @param string|null $message
+     * @return RpcError|null
+     */
+    public function produceError(StandardError $error, ?string $message=null): ?RpcError
+    {
+        if($this->id == null)
+        {
+            return null;
+        }
+
+        if($message == null)
+        {
+            $message = $error->getMessage();
+        }
+
+        return new RpcError($this->id, $error, $message);
+    }
+
+    /**
+     * @param StandardException $e
+     * @return RpcError|null
+     */
+    public function handleStandardException(StandardException $e): ?RpcError
+    {
+        return $this->produceError($e->getStandardError(), $e->getMessage());
+    }
+
     /**
      * Returns an array representation of the object.
      *
@@ -74,6 +174,6 @@ class RpcRequest implements SerializableInterface
      */
     public static function fromArray(array $data): RpcRequest
     {
-        return static($data);
+        return new RpcRequest($data['method'], $data['id'] ?? null, $data['parameters'] ?? null);
     }
 }

src/Socialbox/Objects/RpcResponse.php

@@ -7,15 +7,15 @@ use Socialbox\Interfaces\SerializableInterface;
 class RpcResponse implements SerializableInterface
 {
     private string $id;
-    private ?object $result;
+    private mixed $result;
 
     /**
      * Constructs the response object.
      *
      * @param string $id The ID of the response.
-     * @param object|null $result The result of the response.
+     * @param mixed|null $result The result of the response.
      */
-    public function __construct(string $id, ?object $result)
+    public function __construct(string $id, mixed $result)
     {
         $this->id = $id;
         $this->result = $result;
@@ -34,13 +34,37 @@ class RpcResponse implements SerializableInterface
     /**
      * Returns the result of the response.
      *
-     * @return object|null The result of the response.
+     * @return mixed|null The result of the response.
      */
-    public function getResult(): ?object
+    public function getResult(): mixed
     {
         return $this->result;
     }
 
+    /**
+     * Converts the given data to an array.
+     *
+     * @param mixed $data The data to be converted. This can be an instance of SerializableInterface, an array, or a scalar value.
+     * @return mixed The converted data as an array if applicable, or the original data.
+     */
+    private function convertToArray(mixed $data): mixed
+    {
+        // If the data is an instance of SerializableInterface, call toArray on it
+        if ($data instanceof SerializableInterface)
+        {
+            return $data->toArray();
+        }
+
+        // If the data is an array, recursively apply this method to each element
+        if (is_array($data))
+        {
+            return array_map([$this, 'convertToArray'], $data);
+        }
+
+        // Otherwise, return the data as-is (e.g., for scalar values)
+        return $data;
+    }
+
     /**
      * Returns an array representation of the object.
      *
@@ -50,7 +74,7 @@ class RpcResponse implements SerializableInterface
     {
         return [
             'id' => $this->id,
-            'result' => $this->result->toArray()
+            'result' => $this->convertToArray($this->result)
         ];
     }
 

src/Socialbox/Objects/SessionRecord.php

@@ -0,0 +1,82 @@
+<?php
+
+namespace Socialbox\Objects;
+
+use DateTime;
+use Socialbox\Enums\SessionState;
+use Socialbox\Interfaces\SerializableInterface;
+
+class SessionRecord implements SerializableInterface
+{
+    private string $uuid;
+    private ?string $authenticatedPeerUuid;
+    private string $publicKey;
+    private SessionState $state;
+    private DateTime $created;
+    private DateTime $lastRequest;
+
+    public function __construct(array $data)
+    {
+        $this->uuid = $data['uuid'];
+        $this->authenticatedPeerUuid = $data['authenticated_peer_uuid'] ?? null;
+        $this->publicKey = $data['public_key'];
+        $this->created = $data['created'];
+        $this->lastRequest = $data['last_request'];
+
+        if(SessionState::tryFrom($data['state']) == null)
+        {
+            $this->state = SessionState::CLOSED;
+        }
+        else
+        {
+            $this->state = SessionState::from($data['state']);
+        }
+    }
+
+    public function getUuid(): string
+    {
+        return $this->uuid;
+    }
+
+    public function getAuthenticatedPeerUuid(): ?string
+    {
+        return $this->authenticatedPeerUuid;
+    }
+
+    public function getPublicKey(): string
+    {
+        return $this->publicKey;
+    }
+
+    public function getState(): SessionState
+    {
+        return $this->state;
+    }
+
+    public function getCreated(): int
+    {
+        return $this->created;
+    }
+
+    public function getLastRequest(): int
+    {
+        return $this->lastRequest;
+    }
+
+    public static function fromArray(array $data): object
+    {
+        return new self($data);
+    }
+
+    public function toArray(): array
+    {
+        return [
+            'uuid' => $this->uuid,
+            'authenticated_peer_uuid' => $this->authenticatedPeerUuid,
+            'public_key' => $this->publicKey,
+            'state' => $this->state->value,
+            'created' => $this->created,
+            'last_request' => $this->lastRequest,
+        ];
+    }
+}

src/Socialbox/Socialbox.php

@@ -1,8 +1,54 @@
 <?php
 
-    namespace socialbox;
+    namespace Socialbox;
+
+    use Socialbox\Classes\RpcHandler;
+    use Socialbox\Enums\StandardError;
+    use Socialbox\Enums\StandardMethods;
+    use Socialbox\Exceptions\RpcException;
 
     class Socialbox
     {
-
+        public static function handleRpc(): void
+        {
+            try
+            {
+                $clientRequest = RpcHandler::getClientRequest();
+            }
+            catch(RpcException $e)
+            {
+                http_response_code($e->getCode());
+                print($e->getMessage());
+                return;
+            }
+
+            $results = [];
+            foreach($clientRequest->getRequests() as $rpcRequest)
+            {
+                $method = StandardMethods::tryFrom($rpcRequest->getMethod());
+
+                if($method === false)
+                {
+                    $response = $rpcRequest->produceError(StandardError::RPC_METHOD_NOT_FOUND, 'The requested method does not exist');;
+                    if($response !== null)
+                    {
+                        $results[] = $response;
+                    }
+                }
+
+                $response = $method->execute($clientRequest, $rpcRequest);
+                if($response !== null)
+                {
+                    $results[] = $response;
+                }
+            }
+
+            if(count($results) > 0)
+            {
+                print(json_encode($results));
+                return;
+            }
+
+            http_response_code(204);
+        }
     }