<?php
namespace Socialbox\Classes;
use Socialbox\Enums\StandardHeaders;
use Socialbox\Enums\Types\RequestType;
use Socialbox\Exceptions\CryptographyException;
use Socialbox\Exceptions\DatabaseOperationException;
use Socialbox\Exceptions\ResolutionException;
use Socialbox\Exceptions\RpcException;
use Socialbox\Objects\ExportedSession;
use Socialbox\Objects\KeyPair;
use Socialbox\Objects\PeerAddress;
use Socialbox\Objects\RpcRequest;
use Socialbox\Objects\RpcResponse;
class RpcClient
{
private const string CLIENT_NAME = 'Socialbox PHP';
private const string CLIENT_VERSION = '1.0';
private bool $bypassSignatureVerification;
private PeerAddress $peerAddress;
private KeyPair $keyPair;
private string $encryptionKey;
private string $serverPublicKey;
private string $rpcEndpoint;
private string $sessionUuid;
/**
* Constructs a new instance with the specified peer address.
*
* @param string|PeerAddress $peerAddress The peer address to be used for the instance (eg; johndoe@example.com)
* @param ExportedSession|null $exportedSession Optional. An exported session to be used to re-connect.
* @throws CryptographyException If there is an error in the cryptographic operations.
* @throws RpcException If there is an error in the RPC request or if no response is received.
* @throws DatabaseOperationException If there is an error in the database operations.
* @throws ResolutionException If there is an error in the resolution process.
*/
public function __construct(string|PeerAddress $peerAddress, ?ExportedSession $exportedSession=null)
{
$this->bypassSignatureVerification = false;
// If an exported session is provided, no need to re-connect.
if($exportedSession !== null)
{
$this->peerAddress = PeerAddress::fromAddress($exportedSession->getPeerAddress());
$this->keyPair = new KeyPair($exportedSession->getPublicKey(), $exportedSession->getPrivateKey());
$this->encryptionKey = $exportedSession->getEncryptionKey();
$this->serverPublicKey = $exportedSession->getServerPublicKey();
$this->rpcEndpoint = $exportedSession->getRpcEndpoint();
$this->sessionUuid = $exportedSession->getSessionUuid();
return;
}
// If the peer address is a string, we need to convert it to a PeerAddress object
if(is_string($peerAddress))
{
$peerAddress = PeerAddress::fromAddress($peerAddress);
}
// Set the initial properties
$this->peerAddress = $peerAddress;
$this->keyPair = Cryptography::generateKeyPair();
$this->encryptionKey = Cryptography::generateEncryptionKey();
// Resolve the domain and get the server's Public Key & RPC Endpoint
$resolvedServer = ServerResolver::resolveDomain($this->peerAddress->getDomain(), false);
$this->serverPublicKey = $resolvedServer->getPublicKey();
$this->rpcEndpoint = $resolvedServer->getEndpoint();
// Attempt to create an encrypted session with the server
$this->sessionUuid = $this->createSession();
$this->sendDheExchange();
}
/**
* Creates a new session by sending an HTTP GET request to the RPC endpoint.
* The request includes specific headers required for session initiation.
*
* @return string Returns the session UUID received from the server.
* @throws RpcException If the server response is invalid, the session creation fails, or no session UUID is returned.
*/
private function createSession(): string
{
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $this->rpcEndpoint);
curl_setopt($ch, CURLOPT_HTTPGET, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
StandardHeaders::REQUEST_TYPE->value . ': ' . RequestType::INITIATE_SESSION->value,
StandardHeaders::CLIENT_NAME->value . ': ' . self::CLIENT_NAME,
StandardHeaders::CLIENT_VERSION->value . ': ' . self::CLIENT_VERSION,
StandardHeaders::PUBLIC_KEY->value . ': ' . $this->keyPair->getPublicKey(),
StandardHeaders::IDENTIFY_AS->value . ': ' . $this->peerAddress->getAddress(),
]);
$response = curl_exec($ch);
if($response === false)
{
curl_close($ch);
throw new RpcException('Failed to create the session, no response received');
}
$responseCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
if($responseCode !== 201)
{
curl_close($ch);
throw new RpcException('Failed to create the session, server responded with ' . $responseCode . ': ' . $response);
}
if(empty($response))
{
curl_close($ch);
throw new RpcException('Failed to create the session, server did not return a session UUID');
}
curl_close($ch);
return $response;
}
/**
* Sends a Diffie-Hellman Ephemeral (DHE) exchange request to the server.
*
* @throws RpcException If the encryption or the request fails.
*/
private function sendDheExchange(): void
{
// Request body should contain the encrypted key, the client's public key, and the session UUID
// Upon success the server should return 204 without a body
try
{
$encryptedKey = Cryptography::encryptContent($this->encryptionKey, $this->serverPublicKey);
}
catch (CryptographyException $e)
{
throw new RpcException('Failed to encrypt DHE exchange data', 0, $e);
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $this->rpcEndpoint);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
StandardHeaders::REQUEST_TYPE->value . ': ' . RequestType::DHE_EXCHANGE->value,
StandardHeaders::SESSION_UUID->value . ': ' . $this->sessionUuid,
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, $encryptedKey);
$response = curl_exec($ch);
if($response === false)
{
curl_close($ch);
throw new RpcException('Failed to send DHE exchange, no response received');
}
$responseCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
if($responseCode !== 204)
{
curl_close($ch);
throw new RpcException('Failed to send DHE exchange, server responded with ' . $responseCode . ': ' . $response);
}
curl_close($ch);
}
/**
* Sends an RPC request with the given JSON data.
*
* @param string $jsonData The JSON data to be sent in the request.
* @return array An array of RpcResult objects.
* @throws RpcException If the request fails, the response is invalid, or the decryption/signature verification fails.
*/
public function sendRawRequest(string $jsonData): array
{
try
{
$encryptedData = Cryptography::encryptTransport($jsonData, $this->encryptionKey);
$signature = Cryptography::signContent($jsonData, $this->keyPair->getPrivateKey());
}
catch (CryptographyException $e)
{
throw new RpcException('Failed to encrypt request data: ' . $e->getMessage(), 0, $e);
}
$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, $this->rpcEndpoint);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, [
StandardHeaders::REQUEST_TYPE->value . ': ' . RequestType::RPC->value,
StandardHeaders::SESSION_UUID->value . ': ' . $this->sessionUuid,
StandardHeaders::SIGNATURE->value . ': ' . $signature,
'Content-Type: application/encrypted-json',
]);
curl_setopt($ch, CURLOPT_POSTFIELDS, $encryptedData);
$response = curl_exec($ch);
if ($response === false)
{
curl_close($ch);
throw new RpcException('Failed to send request, no response received');
}
$responseCode = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
$responseString = $response;
if (!Utilities::isSuccessCodes($responseCode))
{
curl_close($ch);
if (!empty($responseString))
{
throw new RpcException($responseString);
}
throw new RpcException('Failed to send request (Empty Response): ' . $responseCode);
}
if ($responseCode == 204)
{
curl_close($ch);
return [];
}
if (empty($responseString))
{
curl_close($ch);
throw new RpcException('The request was successful but the server did not indicate an empty response');
}
curl_close($ch);
try
{
$decryptedResponse = Cryptography::decryptTransport($responseString, $this->encryptionKey);
}
catch (CryptographyException $e)
{
throw new RpcException('Failed to decrypt response: ' . $e->getMessage(), 0, $e);
}
if (!$this->bypassSignatureVerification)
{
$signature = curl_getinfo($ch, CURLINFO_HEADER_OUT)['Signature'] ?? null;
if ($signature === null)
{
throw new RpcException('The server did not provide a signature for the response');
}
try
{
if (!Cryptography::verifyContent($decryptedResponse, $signature, $this->serverPublicKey))
{
throw new RpcException('Failed to verify the response signature');
}
}
catch (CryptographyException $e)
{
throw new RpcException('Failed to verify the response signature: ' . $e->getMessage(), 0, $e);
}
}
$decoded = json_decode($decryptedResponse, true);
if (is_array($decoded))
{
$results = [];
foreach ($decoded as $responseMap)
{
$results[] = RpcResponse::fromArray($responseMap);
}
return $results;
}
if (is_object($decoded))
{
return [RpcResponse::fromArray((array)$decoded)];
}
throw new RpcException('Failed to decode response');
}
/**
* Sends an RPC request and retrieves the corresponding RPC response.
*
* @param RpcRequest $request The RPC request to be sent.
* @return RpcResponse The received RPC response.
* @throws RpcException If no response is received from the request.
*/
public function sendRequest(RpcRequest $request): RpcResponse
{
$response = $this->sendRawRequest(json_encode($request));
if (count($response) === 0)
{
throw new RpcException('Failed to send request, no response received');
}
return $response[0];
}
/**
* Sends a batch of requests to the server, processes them into an appropriate format,
* and handles the response.
*
* @param RpcRequest[] $requests An array of RpcRequest objects to be sent to the server.
* @return RpcResponse[] An array of RpcResponse objects received from the server.
* @throws RpcException If no response is received from the server.
*/
public function sendRequests(array $requests): array
{
$parsedRequests = [];
foreach ($requests as $request)
{
$parsedRequests[] = $request->toArray();
}
$responses = $this->sendRawRequest(json_encode($parsedRequests));
if (count($responses) === 0)
{
throw new RpcException('Failed to send requests, no response received');
}
return $responses;
}
/**
* Exports the current session details into an ExportedSession object.
*
* @return ExportedSession The exported session containing session-specific details.
*/
public function exportSession(): ExportedSession
{
return new ExportedSession([
'peer_address' => $this->peerAddress->getAddress(),
'private_key' => $this->keyPair->getPrivateKey(),
'public_key' => $this->keyPair->getPublicKey(),
'encryption_key' => $this->encryptionKey,
'server_public_key' => $this->serverPublicKey,
'rpc_endpoint' => $this->rpcEndpoint,
'session_uuid' => $this->sessionUuid
]);
}
}