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<?php
////Handels quiz answers
////Parameters: loginName, courseName, courseOccasion, quizNr, 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
session_start();
//Check if the sent login name is the same as the one stored in the session
if($_POST['loginName']==$_SESSION['loginName'] && $_POST['courseName']==$_SESSION['courseName'] && $_POST['quizNr']==$_SESSION['quizNr']) {
include "../../php/dbconnect.php";
//Store answer and loginName+answer hash
function storeAnswer($loginName,$courseName,$courseOccasion,$quizNr,$qVarRr,$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 AssignedQuizzes.quizNr=:QNR
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(':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', $dateString); // date and time formated to string e.g. "2012-08-23 08:59:00"
$updateStmt->bindParam(':IP',$ip);
$updateStmt->bindParam(':AGENT',$userAgent);
return $updateStmt->execute();
}
//Prevents browsers (IE) from caching the response
header('Cache-Control: no-cache, must-revalidate');
header('Expires: Mon, 26 Jul 1997 05:00:00 GMT');
header('Content-type: application/json; charset=utf-8');
//TODO: Store ALL answer attempts in answerlog
// CREATE TABLE AssignedQuizzesAnswerLog(
// ssn CHAR(11), /*YYMMDD-XXXX*/
// loginName VARCHAR(50),
// quizNr INTEGER,
// qVarNr INTEGER,
// quizCourseName VARCHAR(200),
// courseOccasion VARCHAR(25),
// answerHash VARCHAR(255), /*Hash of Student login name + answer */
// answer TEXT,
// grade VARCHAR(10),
// gradeComment TEXT,
// answeredDateTime TIMESTAMP,
// userAgent VARCHAR(1024), /*$_SERVER['HTTP_USER_AGENT']*/
// userIP VARCHAR(20) /*$_SERVER['REMOTE_ADDR']*/
// ) ENGINE=INNODB CHARACTER SET utf8 COLLATE utf8_swedish_ci;
$insertString = "INSERT INTO AssignedQuizzesAnswerLog(
ssn,
loginName,
quizNr,
qVarNr,
quizCourseName,
courseOccasion,
answerHash,
answer,
grade,
gradeComment,
answeredDateTime,
userAgent,
userIP)
VALUES(
(SELECT Student.ssn FROM Student WHERE Student.loginName=:LOGIN),
:LOGIN,
:QNR,
(SELECT AssignedQuizzes.qVarNr
FROM AssignedQuizzes, Student
WHERE Student.ssn=AssignedQuizzes.ssn
AND AssignedQuizzes.quizNr=:QNR
AND Student.loginName=:LOGIN
AND AssignedQuizzes.quizCourseName=:CNAME
AND AssignedQuizzes.courseOccasion=:COCCASION),
:CNAME,
:COCCASION,
:AHASH,
:ANSWER,
'',
'',
:ADATETIME,
:UAGENT,
:UIP);";
$stmt = $pdo->prepare($insertString);
$stmt->bindParam(':QNR', $_POST['quizNr']);
$stmt->bindParam(':LOGIN', $_POST['loginName']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->bindParam(':COCCASION', $_POST['courseOccasion']);
$stmt->bindParam(':ANSWER', $_POST['quizAnswer']);
$hashedAnswer=md5($_POST['loginName'].$_POST['quizAnswer']);
$stmt->bindParam(':AHASH', $hashedAnswer);
$stmt->bindParam(':UAGENT', $_SERVER['HTTP_USER_AGENT']);
$now=new DateTime();
$dateString=$now->format('Y-m-d H:i:s');
$stmt->bindParam(':ADATETIME', $dateString); // date and time formated to string e.g. "2012-08-23 08:59:00"
$stmt->bindParam(':UIP', $_SERVER['REMOTE_ADDR']);
$stmt->execute();
//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', $_SESSION['loginName']);
$stmt->bindParam(':PASSW', $_SESSION['password']);
$stmt->bindParam(':CNAME', $_SESSION['courseName']);
$stmt->bindParam(':COCCASION', $_SESSION['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, Quiz.allowMultipleReplies
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, AssignedQuizzes.qVarNr, AssignedQuizzes.gradeComment
FROM AssignedQuizzes, Student
WHERE Student.ssn=AssignedQuizzes.ssn
AND AssignedQuizzes.quizNr=:QNR
AND Student.loginName=:LOGIN
AND AssignedQuizzes.quizCourseName=:CNAME
AND AssignedQuizzes.courseOccasion=:COCCASION;";
$stmt = $pdo->prepare($queryString);
$stmt->bindParam(':QNR', $_POST['quizNr']);
$stmt->bindParam(':LOGIN', $_POST['loginName']);
$stmt->bindParam(':CNAME', $_POST['courseName']);
$stmt->bindParam(':COCCASION', $_POST['courseOccasion']);
$stmt->execute();
$result=$stmt->fetch(PDO::FETCH_ASSOC);
$stmt->closeCursor();
if($result){ //If this quiz is assigned to the student
if($result['answerHash']!=NULL && $quizData['allowMultipleReplies']!='1'){ //Student has already answered the quiz
echo json_encode(array('Error' => 'This quiz has already been answered', 'answerHash'=>$result['answerHash']));
exit();
} else { //check if autoCorrection
if($quizData['autoCorrected']=='0'){ //Not auto corrected
$hashedAnswer= substr(md5($_POST['loginName'].$_POST['quizAnswer']),0,8);
if(storeAnswer($_POST['loginName'],
$_POST['courseName'],
$_POST['courseOccasion'],
$_POST['quizNr'],
$result['qVarNr'],
$_POST['quizAnswer'],
"ungraded",
$result['gradeComment']."-",
$_SERVER['REMOTE_ADDR'],
$_SERVER['HTTP_USER_AGENT'],
$pdo)){
//Stored answer
echo json_encode(array('Success' => 'true','hashedAnswer' => $hashedAnswer));
} else {
//Failed to store answer
echo json_encode(array('Success' => 'false','hashedAnswer' => $hashedAnswer));
}
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', $result['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
$hashedAnswer= substr(md5($_POST['loginName'].$_POST['quizAnswer']),0,8);
$stmt->closeCursor();
if(storeAnswer($_POST['loginName'],
$_POST['courseName'],
$_POST['courseOccasion'],
$_POST['quizNr'],
$result['qVarNr'],
$_POST['quizAnswer'],
"Correct",
$result['gradeComment']." 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'));
exit();
}
} else { //Sent login name does not match the login name stored in the session
echo json_encode(array('Error' => 'Sent login name does not match stored login name'));
}
?>
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