php checkdate，单独检查每个参数

Question

I am trying to learn about managing dates on mysql, and I have been given an exercise to practise it.

On an input, the user must add a date formated as dd-mm-YYYY, and then, if the date is valid, I record in on the database, changing the format to YYYY-mm-dd as it is how DATE variable types are stored (as I understood), but, I haven't arrived yet...

This is what I have so far:

html

  <form method="POST" action="testing.php">   
        <div>
          <label for="title" class="required">Title</label>
          <input name="title" id="title" type="text" value="" />
        </div>
        <div>
          <label for="date" class="required">Date</label>
           <input name="date" id="date" type="date" value="" />
        </div>
        <button class="submit" type="submit" name="submit">Submit</button>
      </form>

php

if ($_SERVER['REQUEST_METHOD'] == 'POST') {
    $title = filter_input(INPUT_POST, 'title', FILTER_SANITIZE_STRING);
    $string_input_date = filter_input(INPUT_POST, 'date', FILTER_SANITIZE_STRING);
   $array_input_date = explode("-", $string_input_date);
  if(!checkdate($array_input_date[1], $array_input_date[0], $array_input_date[2])) { 

       if(checkdate(!$array_input_date[1], $array_input_date[0], $array_input_date[2])) {
            $error_message = "wrong month";  die($error_message);
        } elseif (checkdate($array_input_date[1], !$array_input_date[0], $array_input_date[2])) {
            $error_message = "wrong day";  
        } elseif (checkdate($array_input_date[1], $array_input_date[0], !$array_input_date[2])) {
            $error_message = "wrong year";  
        } else {
              $error_message = "Introduce a valid date"; 
        }  
    } else {
        //success! it is a valid date
    }
} 

I can see, it isn't working, but I run out of options about how can I check each argument one per one... The objective is, I have to display an error message if it is the day what is wrong, or the month, or the year.

At the moment, I try to introduce 35-04-2016 which should display the error message "wrong day", but instead it displays "Introduce a valid date". I know it is displaying that because my if-elseif are wrong but... any suggestion about how to check each argument separately?

P.S.: I know I could do it with regular expressions, or just creating myself rules like a month is between 1-12 etc etc, but my mentor says I have to use php features and built in functions.... so I CAN'T solve it creating my own rules or with regular expressions (for now, I guess if he sees me crying he might tell me to do whatever I want ^^)

Thank you

Answer 1

checkdate() only returns true or false based on whole date, it won't tell you which part is wrong.

If you want to know which part is wrong, you need to check one by one.

if(!checkdate($array_input_date[1], $array_input_date[0], 
    $array_input_date[2])) 
        { 
            if($array_input_date[1] < 0 || $array_input_date[1] > 12) 
            {
                $error_message = "wrong month";  die($error_message);
            } 
            elseif($array_input_date[2] < 0) 
            {
                $error_message = "wrong year";  
            } 
            else
            {
                $last_day = cal_days_in_month(CAL_GREGORIAN, $array_input_date[1], $array_input_date[2]);
                if($array_input_date[0] < 0 || $array_input_date[0] > $last_day)
                {
                    $error_message = "wrong day";
                }
            }
        }