How to split if else error condition - php

Question

I have a validation with some if/else statements.
<?php
if (isset($_POST["join"])) {
if ($userpoint < $lessonpoint) { //pt
echo "you need more points";
} //pt
else { //has enough point
if ($row['num'] > 0) { //check if user took this lesson
echo "you took this lesson before.";
} //check if user took this lesson ends
else { //then let him apply to database
//define post:
$postvalue = (int)$_POST["postvalue"];
//and check
if($postvalue == '' || $postvalue <= 0 || $postvalue > $minimumpostvalue || $postvalue == is_int($postvalue)) { //check post
echo "Error.";
} //checkpost ends.
else { //insert
$sql = "INSERT into etc... VALUES (?, ?, ?)";
if($sql){ //to another database
$artibir = "UPDATE etc.";
echo "Done.";
} // to another database
}//insert
} //let him apply
} //has enough point
} //if post isset join
?>
This works very well.
But I want to echo out another error message for this condition: $postvalue > $minimumpostvalue
While trying it I get lost inside the if/else statements.
Wherever I put new statement I'm having an error.
All variables are defined.
Where and how can I place $postvalue > $minimumpostvalue to echo a different error message?

Answer 1

<?php
if (isset($_POST["join"])) {
if ($userpoint < $lessonpoint) { //pt
echo "you need more points";
} //pt
else { //has enough point
if ($row['num'] > 0) { //check if user took this lesson
echo "you took this lesson before.";
} //check if user took this lesson ends
else { //then let him apply to database
//define post:
$postvalue = (int) $_POST["postvalue"];
//and check
if ($postvalue == '' || $postvalue <= 0 || $postvalue > $minimumpostvalue || $postvalue == is_int($postvalue)) { //check post
if ($postvalue > $minimumpostvalue) {
echo "Another Error.";
}
else {
echo "Error.";
}
} //checkpost ends.
else { //insert
$sql = "INSERT into etc... VALUES (?, ?, ?)";
if ($sql) { //to another database
$artibir = "UPDATE etc.";
echo "Done.";
} // to another database
} //insert
} //let him apply
} //has enough point
} //if post isset join
?>

Answer 2

This is another variation without exceptions.
As soon as $valid becomes false, it will skip the next validation.
<?php
$valid = true;
$error = '';
if ($valid && !isset($_POST["join"])) {
$error = 'Not a join post request';
$valid = false;
}
if ($valid && ($userpoint < $lessonpoint)) {
$error = 'You need more points';
$valid = false;
}
...
if($valid) {
// Database insert; redirect
} else {
// User error feedback
}

Answer 3

//and check
if ($postvalue > $minimumpostvalue) { //check exception
echo "Error 1.";
} elseif ($postvalue == '' || $postvalue <= 0 || $postvalue == is_int($postvalue)) { //check the rest
echo "Error 2.";
} //checkpost ends.

Answer 4

This is untested code, and more an example of how to avoid nested if statements.
The point is to find to state the conditions you have an error state early and exit as soon as you can, at best by throwing an exception and avoiding else statements.
For simplicity I used only \RunTimeException(), yet I would most likely define my own exception depending on the case. The exception then can be caught and depending on their type show a different error page.
/**
* #param int $postvalue
* #param int $minimumpostvalue
*/
function saveToDatabase($postvalue)
{
if ($postvalue == '' || $postvalue <= 0 || $postvalue == is_int($postvalue)) {
throw new \RuntimeException('Error 2');
}
$sql = "INSERT into etc... VALUES (?, ?, ?)";
if ($sql) {
$artibir = "UPDATE etc.";
}
}
if (!isset($_POST["join"])) {
throw new \RuntimeException('Not a join post request');
}
if ($userpoint < $lessonpoint) {
throw new \RuntimeException('You need more points');
}
$userHasTakenCourse = $row['num'] > 0;
if ($userHasTakenCourse) {
throw new \RuntimeException('User has already taken the course.');
}
$postvalue = (int) $_POST["postvalue"];
if ($postvalue > $minimumpostvalue) {
throw new \RuntimeException('Error 1');
}
saveToDatabase($postvalue);