CS 4312 Lab 16

CS 4312 - Lab 16

Description:

The code for the form to be utilized for this assignment is shown below. This needs to be saved as a PHP file (e.g., lab16_form.php).

<!--
  Mark Motl
  CS 4312
  Lab 16
-->
<?php
/* Check the protocol for this request. Redirect an HTTP request to
   an HTTPS request.
   Ref.: https://stackoverflow.com/questions/5106313/redirecting-from-http-to-https-with-php
*/
  if (empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] === "off")
  {
    $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $location);
    exit;
  }
?>
<!DOCTYPE html>
<html lang="en">
<head>
<title>Lab 16 Day Number</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<h1>Lab 16 Day Number</h1>

<p>
This form allows a user to enter a month, day, and year.  The
associated PHP application determines the day number of the given
date.
</p>

<form action="lab16.php" method="post">
<p>
Select the month
</p>
<table>
<?php
  $monthNames = array("January", "February", "March", "April", "May",
                      "June", "July", "August", "September",
                      "October", "November", "December");

  foreach ($monthNames as $i => $month)
  {
    if ($i % 4 == 0)
      echo "<tr>\n";

    echo "<td><input type=\"radio\" name=\"month\" value=\"", $i + 1, "\"";
    if ($i == 0)
      echo " checked=\"checked\"";
    echo " />$month</td>\n";
    if (($i + 1) % 4 == 0)
      echo"</tr>\n";
  }
?>
</table>

<hr />

<p>
Select the day of the month
<select size="1" name="day">
<?php
  for ($i = 1; $i<=31; ++$i)
  {
    echo "<option";
    if ($i == 1)
      echo " selected=\"selected\"";
    echo ">$i</option>\n";
  }
?>
</select>
</p>

<hr />

<p>
Enter the year
<input type="text" name="year" size="4" maxlength="4" /><br /><br />
<input type="reset"  value="Clear This Form" />&nbsp;&nbsp;
<input type="submit" name="Submit" value="Submit This Form" />
</p>
</form>

<p>
<?php 
  $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
  $location = urlencode($location);
  echo '<a href="https://validator.w3.org/nu/?doc=' . $location . '">';
?>
  <img src="https://www.w3.org/QA/Tools/I_heart_validator"
   alt="I heart Validator logo" height="31" width="80" />
</a>
</p>

</body>
</html>

Your program must work when it is invoked through a form using the POST method: lab16_form.php
Your program must also work when it is invoked through a URL using the GET method:

I would suggest using the following leap year form and its associated PHP application (both shown below) when completing this assignment. The code for the HTML form is shown below:

<!--
  Mark Motl
  CS 4312
  Leap Year Example
-->
<?php
/* Check the protocol for this request. Redirect an HTTP request to
   an HTTPS request.
   Ref.: https://stackoverflow.com/questions/5106313/redirecting-from-http-to-https-with-php
*/
  if (empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] === "off")
  {
    $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $location);
    exit;
  }
?>
<!DOCTYPE html>
<html lang="en">
<head>
<title>Leap Year</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<h1>Leap Year</h1>

<p>
This is a sample form that allows a user to enter a text value that
represents a year. The associated PHP application determines if the
input year was/is/will be a leap year.
</p>

<p>
A leap year is defined as a year in the Gregorian calendar
containing 366 days with February 29<sup>th</sup> as the extra
day.  Leap years are those years divisible by 4, except those years
that complete centuries (that is, divisible by 100) which must be
divisible by 400.  Thus, 1998 was not a leap year, 1996 was, 2000
was, 1900 was not, 1600 was, 2100 will not be, 2028 will be, etc.
</p>

<form action="leapyear.php" method="post">
<p>
Enter the year
<input type="text" name="year" size="4" maxlength="4" /><br /></p>
<p><input type="reset"  value="Clear This Form" />&nbsp;&nbsp;
<input type="submit" name="Submit" value="Submit This Form" />
</p>
</form>

<p>
<?php 
  $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
  $location = urlencode($location);
  echo '<a href="https://validator.w3.org/nu/?doc=' . $location . '">';
?>
  <img src="https://www.w3.org/QA/Tools/I_heart_validator"
   alt="I heart Validator logo" height="31" width="80" />
</a>
</p>

</body>
</html>

The code for the PHP application program is shown below:

<!--
  Mark Motl
  CS 4312
  Leap Year Example
-->
<?php
/* Check the protocol for this request. Redirect an HTTP request to
   an HTTPS request.
   Ref.: https://stackoverflow.com/questions/5106313/redirecting-from-http-to-https-with-php
*/
  if (empty($_SERVER['HTTPS']) || $_SERVER['HTTPS'] === "off")
  {
    $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
    header('HTTP/1.1 301 Moved Permanently');
    header('Location: ' . $location);
    exit;
  }
?>
<!DOCTYPE html>
<html lang="en">
<head>
<title>Leap Year</title>
<meta http-equiv="content-type" content="text/html; charset=utf-8" />
</head>
<body>
<?php
  /* -------------------  Function: ParseFormElements ----- */
  function parseFormElements($name)
  {
    if (strcasecmp($_SERVER['REQUEST_METHOD'], "get") == 0)
    {
      if (strstr($_SERVER['QUERY_STRING'], $name) != NULL)
        if ($_GET[$name] == NULL)
          errorMsg("variable " . $name . " is empty");
        else
          return htmlspecialchars($_GET[$name]);
      else
        errorMsg("variable " . $name . " is missing");
    }

    elseif (strcasecmp($_SERVER['REQUEST_METHOD'], "post") == 0)
    {
      if ($_POST[$name] == NULL)
        errorMsg("variable " . $name . " is empty");
      else
        return htmlspecialchars($_POST[$name]);
    }

    else
      errorMsg("unknown REQUEST_METHOD");
  }

  /* -------------------  Function: errorMsg -------------- */
  function errorMsg($msg)
  {
    echo "<p>Your form results could not be processed because "
       . $msg . ".</p>\n";
    writeClosing();
    exit(1);
  }

  echo "<p>Mark Motl - CS 4312 - Leap Year Example<br /></p>\n";

  $year = parseFormElements("year");
  if (!preg_match("/^[0-9]{1,4}$/", $year))
    errorMsg("the value entered for the year, namely, $year is invalid");

  // Ensure the year is in the Gregorian calendar
  if ($year <= 1582)
    errorMsg("the value entered for the year, namely, $year is not in the "
             . "Gregorian calendar.  Use a year later than 1582.");

  echo "<p>$year ";

  date_default_timezone_set('America/Chicago');
  $myTimeArray = getdate();

  if ($year % 400 == 0 || ($year % 4 == 0 && $year % 100 != 0))
  {
    if ($year < $myTimeArray['year'])
      echo "was ";
    else if ($year == $myTimeArray['year'])
      echo "is ";
    else
      echo "will be ";
  }
  else
  {
    if ($year < $myTimeArray['year'])
      echo "was not ";
    else if ($year == $myTimeArray['year'])
      echo "is not ";
    else
      echo "will not be ";
  }

  echo "a leap year.<br /></p>\n";

  writeClosing();
?>

<?php
  /* -------------------  Function: writeClosing ---------- */
  function writeClosing()
  {
?>
<p>
<?php 
  $location = 'https://' . $_SERVER['HTTP_HOST'] . $_SERVER['REQUEST_URI'];
  $location = urlencode($location);
  echo '<a href="https://validator.w3.org/nu/?doc=' . $location . '">';
?>
  <img src="https://www.w3.org/QA/Tools/I_heart_validator"
   alt="I heart Validator logo" height="31" width="80" />
</a>
</p>

</body>
</html>
<?php
  }
?>

The leap year program can use a form to determine if a year was/is/will be a leap year. The input year is obtained from the form using a POST method.
Use the leap year form
The associated program that processes this form can also be invoked using a URL instead of the form using a GET method

Time of Request: Fri 13 Mar 2026 08:20:15 AM CDT
Mark B. Motl
Mark.Motl@angelo.edu