How to pass a mySQLi prepared statement to a function [closed] - php

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I have a mySQLi prepared statement and a function I want to pass it to to check to see if the input meets the right format before executing it. I have determined in my actual code that if I move the $stmt->execute() statement just outside of the function that it works, but inside the function it does not. I know that an old school concatenated SQL string can be passed like this, but what is the right way to handle this with prepared statements?
function validateForm($stmt, $inputType){
// A bunch of stuff here to validate for $inputType.
$stmt->execute();
}
$editSQL = "UPDATE mytable SET input1 = ?, input2 = ?, input3 = ? WHERE thisID = ?";
$stmt = $conn->prepare($editSQL);
$stmt->bind_param('sibi', $input1, $input2, $input3, $thisID);
$input1 = $vPara[1][5];
$input2 = $vPara[2][5];
$input3 = $vPara[3][5];
$thisID = $_SESSION['thisID'];
validateForm($stmt, $inputType);
The specific error I get is:
Fatal error: Call to a member function execute() on a non-object

Answer 1

I don't see why it could potentially not work.
You mentioned that if you use execute outside of this function it works. So leave it the way it works because That's recommended due to Single responsibility principle.
Your validator should not be responsible for executing statements but
only for what its name says = validation.
The only thing that validator should do is to return true or false
and upon that decision, you should make execution or not
so change your code to the following:
<?php
function isFormValid($inputType)
{
// A bunch of stuff here to validate for $inputType.
if (//test cases) {
$validationResult = true;
} else {
$validationResult = false;
}
return $validationResult;
}
$editSQL = "UPDATE mytable SET input1 = ?, input2 = ?, input3 = ? WHERE thisID = ?";
$stmt = $conn->prepare($editSQL);
$stmt->bind_param('sibi', $input1, $input2, $input3, $thisID);
$input1 = $vPara[1][5];
$input2 = $vPara[2][5];
$input3 = $vPara[3][5];
$thisID = $_SESSION['thisID'];
if(isFormValid($inputType)) {
$stmt->execute();
} else {
//do error processing echo, trow exception etc
}
?>
Note that I changed the validator name, so now it really expresses what it does, instead of being called validateForm but actually doing also a statement execution.