ParticipantService - getSurveyParticipants() method - catch and serve an exception while fetching participants of given survey

src/Exception/CannotProcessDataException.php

@@ -16,6 +16,13 @@ namespace Meritoo\LimeSurvey\ApiClient\Exception;
  */
 class CannotProcessDataException extends \Exception
 {
+    /**
+     * Reason why data cannot be processed, e.g. "Invalid user name or password"
+     *
+     * @var string
+     */
+    private $reason;
+
     /**
      * Class constructor
      *
@@ -23,9 +30,21 @@ class CannotProcessDataException extends \Exception
      */
     public function __construct($reason)
     {
+        $this->reason = $reason;
+
         $template = 'Raw data returned by the LimeSurvey\'s API cannot be processed. Reason: \'%s\'.';
-        $message = sprintf($template, $reason);
+        $message = sprintf($template, $this->reason);
 
         parent::__construct($message);
     }
+
+    /**
+     * Returns reason why data cannot be processed, e.g. "Invalid user name or password"
+     *
+     * @return string
+     */
+    public function getReason()
+    {
+        return $this->reason;
+    }
 }

src/Service/ParticipantService.php

@@ -10,10 +10,12 @@ namespace Meritoo\LimeSurvey\ApiClient\Service;
 
 use Meritoo\Common\Collection\Collection;
 use Meritoo\LimeSurvey\ApiClient\Client\Client;
+use Meritoo\LimeSurvey\ApiClient\Exception\CannotProcessDataException;
 use Meritoo\LimeSurvey\ApiClient\Exception\MissingParticipantOfSurveyException;
 use Meritoo\LimeSurvey\ApiClient\Result\Collection\Participants;
 use Meritoo\LimeSurvey\ApiClient\Result\Item\Participant;
 use Meritoo\LimeSurvey\ApiClient\Type\MethodType;
+use Meritoo\LimeSurvey\ApiClient\Type\ReasonType;
 
 /**
  * Service that serves participants
@@ -69,6 +71,8 @@ class ParticipantService
      *
      * @param int $surveyId ID of survey
      * @return Collection
+     *
+     * @throws CannotProcessDataException
      */
     public function getSurveyParticipants($surveyId)
     {
@@ -81,10 +85,24 @@ class ParticipantService
                 $surveyId,
             ];
 
-            $participants = $this
-                ->client
-                ->run(MethodType::LIST_PARTICIPANTS, $arguments)
-                ->getData();
+            try {
+                $participants = $this
+                    ->client
+                    ->run(MethodType::LIST_PARTICIPANTS, $arguments)
+                    ->getData();
+            } catch (CannotProcessDataException $exception) {
+                $reason = $exception->getReason();
+
+                /*
+                 * Reason of the exception is different than "Oops, there is no participants. Everything else is fine."?
+                 * Let's throw the exception
+                 */
+                if (ReasonType::NO_PARTICIPANTS_FOUND !== $reason) {
+                    throw $exception;
+                }
+
+                $participants = new Collection();
+            }
 
             $this
                 ->allParticipants

src/Type/ReasonType.php

@@ -0,0 +1,28 @@
+<?php
+
+namespace Meritoo\LimeSurvey\ApiClient\Type;
+
+use Meritoo\Common\Type\Base\BaseType;
+
+/**
+ * Type of reason used by LimeSurvey's exception
+ *
+ * @author    Krzysztof Niziol <krzysztof.niziol@meritoo.pl>
+ * @copyright Meritoo.pl
+ */
+class ReasonType extends BaseType
+{
+    /**
+     * Reason of exception when there is no participants of survey
+     *
+     * @var string
+     */
+    const NO_PARTICIPANTS_FOUND = 'No survey participants found.';
+
+    /**
+     * Reason of exception when there is no table with tokens/participants of survey
+     *
+     * @var string
+     */
+    const NO_TOKEN_TABLE = 'Error: No token table';
+}