feat: retry api requests when closed immediately due to overload

src/BusProNet/ApiClient.php

@@ -4,17 +4,18 @@ namespace App\BusProNet;
 
 use App\BusProNet\DataProcessor\BookingDataProcessor;
 use App\BusProNet\Exception\ApiClientException;
+use App\BusProNet\Exception\ImmediateConnectionCloseException;
 use App\BusProNet\Exception\ResponseParserException;
 use App\BusProNet\Model\BaseData;
 use App\BusProNet\Model\Booking;
 use App\BusProNet\Model\BookingResponse;
 use App\BusProNet\Model\BookingUpdate;
-use App\BusProNet\Model\RegistrationResponse;
 use App\BusProNet\Model\CrmAttributes;
 use App\BusProNet\Model\Notification;
 use App\BusProNet\Model\PersonalData;
 use App\BusProNet\Model\PromoVoucher;
 use App\BusProNet\Model\PurchaseVoucher;
+use App\BusProNet\Model\RegistrationResponse;
 use App\BusProNet\Model\ServiceAvailabilityResponse;
 use App\BusProNet\Model\Travel;
 use App\BusProNet\Traits\ApiClientTrait;
@@ -489,10 +490,11 @@ class ApiClient
     }
 
     /**
-     * Sends raw XML to the BPN API with key regeneration.
+     * Sends raw XML to the BPN API with key regeneration and automatic retry.
      *
      * Parses the XML to extract the request type, regenerates the authentication key
      * with the current date, and sends the request. Returns the raw XML response.
+     * Automatically retries on immediate connection close (server busy).
      *
      * @param string $xml   The raw XML request body
      * @param bool   $debug Enable debug mode (XML dumps)
@@ -502,6 +504,42 @@ class ApiClient
      * @throws ApiClientException If the request fails or XML is invalid
      */
     public function sendRawXml(string $xml, bool $debug = false): string
+    {
+        $maxAttempts = $this->config['busy_retry_attempts'];
+        $retryDelay = $this->config['busy_retry_delay'];
+        $lastException = null;
+
+        for ($attempt = 1; $attempt <= $maxAttempts; ++$attempt) {
+            try {
+                return $this->doSendRawXml($xml, $debug);
+            } catch (ImmediateConnectionCloseException $e) {
+                $lastException = $e;
+
+                if ($attempt < $maxAttempts) {
+                    $this->logger->warning('BPN server busy, retrying raw XML request', [
+                        'attempt' => $attempt,
+                        'maxAttempts' => $maxAttempts,
+                        'retryDelay' => $retryDelay,
+                    ]);
+                    sleep($retryDelay);
+                }
+            }
+        }
+
+        $this->logger->error('BPN server busy after all retry attempts (raw XML)', [
+            'attempts' => $maxAttempts,
+        ]);
+
+        throw $lastException;
+    }
+
+    /**
+     * Performs the actual raw XML request to the BPN API.
+     *
+     * @throws ApiClientException
+     * @throws ImmediateConnectionCloseException
+     */
+    private function doSendRawXml(string $xml, bool $debug = false): string
     {
         $requestId = date(DATE_ATOM).uniqid();
 
@@ -565,9 +603,52 @@ class ApiClient
     }
 
     /**
+     * Sends a request to the BPN API with automatic retry on immediate connection close.
+     *
+     * When the BPN server is busy, it may close connections immediately without responding.
+     * This method detects such conditions and automatically retries after a short delay.
+     *
      * @throws ApiClientException
      */
     private function sendRequest(string $type, array $data, array $additionalArgs = [], bool $debug = false): mixed
+    {
+        $maxAttempts = $this->config['busy_retry_attempts'];
+        $retryDelay = $this->config['busy_retry_delay'];
+        $lastException = null;
+
+        for ($attempt = 1; $attempt <= $maxAttempts; ++$attempt) {
+            try {
+                return $this->doSendRequest($type, $data, $additionalArgs, $debug);
+            } catch (ImmediateConnectionCloseException $e) {
+                $lastException = $e;
+
+                if ($attempt < $maxAttempts) {
+                    $this->logger->warning('BPN server busy, retrying request', [
+                        'attempt' => $attempt,
+                        'maxAttempts' => $maxAttempts,
+                        'retryDelay' => $retryDelay,
+                        'type' => $type,
+                    ]);
+                    sleep($retryDelay);
+                }
+            }
+        }
+
+        $this->logger->error('BPN server busy after all retry attempts', [
+            'attempts' => $maxAttempts,
+            'type' => $type,
+        ]);
+
+        throw $lastException;
+    }
+
+    /**
+     * Performs the actual request to the BPN API.
+     *
+     * @throws ApiClientException
+     * @throws ImmediateConnectionCloseException
+     */
+    private function doSendRequest(string $type, array $data, array $additionalArgs = [], bool $debug = false): mixed
     {
         $requestId = date(DATE_ATOM).uniqid();
 
@@ -650,6 +731,8 @@ class ApiClient
             'connection_timeout' => 5,
             'stream_timeout' => 30,
             'total_timeout' => 45,
+            'busy_retry_attempts' => 3,
+            'busy_retry_delay' => 1,
         ]);
 
         return $optionsResolver->resolve($options);

src/BusProNet/Exception/ImmediateConnectionCloseException.php

@@ -0,0 +1,15 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\BusProNet\Exception;
+
+/**
+ * Thrown when the BPN server closes the connection immediately without sending data.
+ *
+ * This typically indicates the server is busy processing other requests.
+ * Unlike a true timeout, this is a transient condition that may succeed on retry.
+ */
+class ImmediateConnectionCloseException extends ApiClientException
+{
+}

src/BusProNet/Traits/ApiClientTrait.php

@@ -3,6 +3,7 @@
 namespace App\BusProNet\Traits;
 
 use App\BusProNet\Exception\ApiClientException;
+use App\BusProNet\Exception\ImmediateConnectionCloseException;
 use App\BusProNet\Exception\TimeoutException;
 
 trait ApiClientTrait
@@ -90,6 +91,7 @@ trait ApiClientTrait
 
     /**
      * @throws TimeoutException
+     * @throws ImmediateConnectionCloseException
      */
     private function receive($socket, int $totalTimeout): string
     {
@@ -115,6 +117,17 @@ trait ApiClientTrait
             // Check if stream timed out on this specific read
             $metadata = stream_get_meta_data($socket);
             if (true === $metadata['timed_out']) {
+                // Check if this is an immediate rejection (0 bytes, < 1 second)
+                // This indicates the server is busy rather than a true timeout
+                if (0 === strlen($response) && $elapsedTime < 1.0) {
+                    $this->logger->warning('Server closed connection immediately', [
+                        'elapsed_time' => $elapsedTime,
+                        'bytes_received' => 0,
+                        'read_attempts' => $readAttempts,
+                    ]);
+                    throw new ImmediateConnectionCloseException('Server closed connection immediately - server may be busy');
+                }
+
                 $this->logger->error('Stream read timeout detected', [
                     'elapsed_time' => $elapsedTime,
                     'bytes_received' => strlen($response),