Users can cancel responses to a survey.

RestControllers/surveysController.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * Restserver controller
+ * 
+ *  Surveys controller
+ * 
+ * @author Pierre HUBERT
+ */
+
+class surveysController {
+
+	/**
+	 * Cancel a response to a survey
+	 * 
+	 * @url POST /surveys/cancel_response
+	 */
+	public function cancel_response(){
+
+		user_login_required();
+
+		//Get the ID of the survey
+		$surveyID = $this->getSurveyIDFromPostID("postID");
+
+		//Try to cancel the user's response to the survey
+		if(!components()->survey->cancel_response($surveyID, userID))
+			Rest_fatal_error(500, "Couldn't cancel user response to the survey !");
+		
+		//Success
+		return array("success" => "The response to the survey was cancelled!");
+
+	}
+
+	/**
+	 * Get the ID of a survey from a $_POST ID
+	 * 
+	 * @param string $name The name of the post field that contains
+	 * associated POST ID
+	 * @return int The ID of the target survey
+	 */
+	private function getSurveyIDFromPostID(string $name) : int {
+
+		//Get the ID of the target post
+		$postID = getPostPostIDWithAccess("postID");
+
+		//Check if a survey is associated with the post
+		$surveyID = components()->survey->get_id($postID);
+
+		//Check for errors
+		if($surveyID == 0)
+			Rest_fatal_error(401, "No survey was found with the specified post !");
+		
+		//Return survey ID
+		return $surveyID;
+
+	}
+
+}

classes/components/survey.php

@@ -128,6 +128,22 @@ class Survey {
 		return $results[0]["ID"];
 	}
 
+	/**
+	 * Cancel the response of a user to a survey
+	 * 
+	 * @param int $surveyID The ID of the target survey
+	 * @param int $userID The ID of the user removing his response
+	 * @return bool FALSE in case of failure / TRUE in case of success
+	 */
+	public function cancel_response(int $surveyID, int $userID) : bool {
+		
+		//Perform a request on the database
+		return CS::get()->db->deleteEntry(
+			$this::SURVEY_RESPONSE_TABLE, 
+			"ID_sondage = ? AND ID_utilisateurs = ?", 
+			array($surveyID, $userID));
+	}
+
 	/**
 	 * Delete the survey associated to a post
 	 *