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<?php
////Handels quiz answers
////Parameters: loginName, password, courseName, courseOccasion, quizNr, qVarNr, quizAnswer
////If autoCorrection==false the answer is stored without checking
////Else the quiz answer is checked for correctness,
//// if incorrect the answer is not stored, else stored
//Store answer and loginName+answer hash
function storeAnswer($loginName,$password,$courseName,$courseOccasion,$quizNr,$qVarNr,$quizAnswer,$grade,$gradeComment,$ip,$userAgent,$pdo) {
$updateQuery="UPDATE AssignedQuizzes
SET AssignedQuizzes.answer=:ANSWER,
AssignedQuizzes.answerHash=:ANSWERHASH,
AssignedQuizzes.grade=:GRADE,
AssignedQuizzes.gradeComment=:GRADECOMMENT,
AssignedQuizzes.answeredDateTime=:DATETIME,
AssignedQuizzes.userAgent=:AGENT,
AssignedQuizzes.userIP=:IP
WHERE AssignedQuizzes.ssn=(SELECT Student.ssn FROM Student WHERE Student.loginName=:LOGIN AND Student.passw=:PASSW)
AND AssignedQuizzes.quizNr=:QNR
AND AssignedQuizzes.qVarNr=:QVNR
AND AssignedQuizzes.quizCourseName=:CNAME
AND AssignedQuizzes.courseOccasion=:COCCASION;";
$updateStmt = $pdo->prepare($updateQuery);
$updateStmt->bindParam(':LOGIN', $loginName);
$updateStmt->bindParam(':CNAME', $courseName);
$updateStmt->bindParam(':QNR', $quizNr);
$updateStmt->bindParam(':QVNR', $qVarNr);
$updateStmt->bindParam(':COCCASION', $courseOccasion);
$updateStmt->bindParam(':ANSWER', $quizAnswer);
$hashedAnswer= md5($loginName.$quizAnswer);
$updateStmt->bindParam(':ANSWERHASH', $hashedAnswer);
$updateStmt->bindParam(':GRADE', $grade);
$updateStmt->bindParam(':GRADECOMMENT', $gradeComment);
$now=new DateTime();
$dateString=$now->format('Y-m-d H:i:s');
//$updateStmt->bindParam(':DATETIME', new DateTime()->format('Y-m-d H:i:s')); // date and time formated to string e.g. "2012-08-23 08:59:00"
$updateStmt->bindParam(':DATETIME', $dateString); // date and time formated to string e.g. "2012-08-23 08:59:00"
$updateStmt->bindParam(':PASSW',$password);
$updateStmt->bindParam(':IP',$ip);
$updateStmt->bindParam(':AGENT',$userAgent);
return $updateStmt->execute();
}
//Prevents browsers (IE) from caching the response
header('Cache-Control: no-cache, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Content-type: application/json; charset=utf-8');
include "dbconnect.php";
//Check if the student is a praticipant of the course
$queryString="SELECT COUNT(*)
FROM Student, StudentCourseRegistration
WHERE Student.ssn=StudentCourseRegistration.studentSsn
AND Student.loginName=:LOGIN
AND Student.passw=:PASSW
AND courseName=:CNAME
AND courseOccasion=:COCCASION;";
$stmt = $pdo->prepare($queryString);
$stmt->bindParam(':LOGIN', $_POST['loginName']);
$stmt->bindParam(':PASSW', $_POST['password']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->bindParam(':COCCASION', $_POST['courseOccasion']);
$stmt->execute();
if($stmt->fetchColumn()==1) { //Student is registered for the course - COUNT result read from the first column of the next unread row (i.e. the first row)
//Check if quiz is open (and fetch auto correction setting)
$queryString="SELECT Quiz.opening, Quiz.closing, Quiz.autoCorrected
FROM Quiz
WHERE Quiz.nr=:QNR
AND Quiz.courseName=:CNAME;";
$stmt = $pdo->prepare($queryString);
$stmt->bindParam(':QNR', $_POST['quizNr']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->execute();
$quizData=$stmt->fetch(PDO::FETCH_ASSOC);
if($quizData) {
$now = new DateTime();
$opening = new DateTime($quizData['opening']);
$closing = new DateTime($quizData['closing']);
if($now<$opening) { //Quiz is not open yet
echo json_encode(array('Error' => 'Requested quiz is not open yet'));
exit();
} else if($now>$closing) { //Quiz is closed
echo json_encode(array('Error' => 'Requested quiz is closed'));
exit();
} // else continue (Not the best coding practice...)
} else { //Quiz does not exist
echo json_encode(array('Error' => 'Requested quiz does not exist'));
exit();
}
/*
AssignedQuizzes(
ssn CHAR(11), //YYMMDD-XXXX
quizNr INTEGER,
qVarNr INTEGER,
quizCourseName VARCHAR(200),
courseOccasion VARCHAR(25) NOT NULL,
answerHash VARCHAR(255), //Hash of Student login name + answer
answer TEXT,
grade VARCHAR(10),
gradeComment TEXT,
answeredDateTime TIMESTAMP,
userAgent VARCHAR(1024),
userIP VARCHAR(20), //$_SERVER['REMOTE_ADDR']
PRIMARY KEY(ssn, qVarNr, quizNr, quizCourseName),
*/
//Check if student already has answered the assigned quiz variant
$queryString="SELECT AssignedQuizzes.answerHash
FROM AssignedQuizzes, Student
WHERE Student.ssn=AssignedQuizzes.ssn
AND AssignedQuizzes.quizNr=:QNR
AND AssignedQuizzes.qVarNr=:QVARNR
AND Student.loginName=:LOGIN
AND AssignedQuizzes.quizCourseName=:CNAME
AND AssignedQuizzes.courseOccasion=:COCCASION;";
$stmt = $pdo->prepare($queryString);
$stmt->bindParam(':QNR', $_POST['quizNr']);
$stmt->bindParam(':QVARNR', $_POST['qVarNr']);
$stmt->bindParam(':LOGIN', $_POST['loginName']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->bindParam(':COCCASION', $_POST['courseOccasion']);
$stmt->execute();
$result=$stmt->fetch(PDO::FETCH_ASSOC);
if($result) { //If there is a quiz variant assigned to the student
if($result['answerHash']!=NULL){ //Student has already answered the quiz
echo json_encode(array('Error' => 'This quiz has already been answered', 'answerHash'=>$result['answerHash']));
exit();
} else { //check if autoCorrection
if($quizData['autoCorrected']=='0') { //Not auto corrected
if(storeAnswer($_POST['loginName'],
$_POST['password'],
$_POST['courseName'],
$_POST['courseOccasion'],
$_POST['quizNr'],
$_POST['qVarNr'],
$_POST['quizAnswer'],
"ungraded",
"-",
$_SERVER['REMOTE_ADDR'],
$_SERVER['HTTP_USER_AGENT'],
$pdo)){
//Stored answer
echo json_encode(array('Success' => 'true'));
} else {
//Failed to store answer
echo json_encode(array('Success' => 'false'));
}
exit();
} else { //Is auto corrected - Check if the correct answer was given
/*QuizVariant(
qVarNr INTEGER,
quizNr INTEGER,
quizCourseName VARCHAR(200),
correctAnswer VARCHAR(255),
quizObjectIDs TEXT,
PRIMARY KEY(qVarNr, quizNr, quizCourseName),
*/
$queryString = "SELECT QuizVariant.correctAnswer
FROM QuizVariant
WHERE QuizVariant.qVarNr=:QVNR
AND QuizVariant.quizNr=:QNR
AND QuizVariant.quizCourseName=:CNAME";
$stmt = $pdo->prepare($queryString);
$stmt->bindParam(':QNR', $_POST['quizNr']);
$stmt->bindParam(':QVNR', $_POST['qVarNr']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->execute();
$qVarData=$stmt->fetch(PDO::FETCH_ASSOC);
$correctAnswer=$qVarData['correctAnswer'];
if($_POST['quizAnswer']==$correctAnswer){ //Correct answer was given
$hashedAnswer= md5($_POST['loginName'].$_POST['quizAnswer']);
if(storeAnswer($_POST['loginName'],
$_POST['password'],
$_POST['courseName'],
$_POST['courseOccasion'],
$_POST['quizNr'],
$_POST['qVarNr'],
$_POST['quizAnswer'],
"Correct",
"Quiz was corrected automatically",
$_SERVER['REMOTE_ADDR'],
$_SERVER['HTTP_USER_AGENT'],
$pdo)){
//Stored answer
echo json_encode(array('Success' => 'true', 'isCorrect' => 'true', 'hashedAnswer' => $hashedAnswer));
} else {
//Failed to store answer
echo json_encode(array('Success' => 'false', 'isCorrect' => 'true', 'hashedAnswer' => $hashedAnswer));
}
exit();
} else { //Answer is incorrect
echo json_encode(array('isCorrect' => 'false'));
}
exit();
}
}
} else {
echo json_encode(array('Error' => 'This student has not been assigned the quiz'));
exit();
}
} else {
echo json_encode(array('Error' => 'Student not registered for this course (or incorrect password was sent)'));
exit();
}
?>
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