为什么我的代码出现PHP致命错误？

Question

I have been wracking my brain for hours now trying to figure out why my code is giving me the error:

PHP Fatal error:  Call to a member function close() on a non-object in /var/www/Garage/ajaxFunctions/ServiceReplication.php on line 24

Here is my code. It is the back end of an AJAX call in my application:

<?php
    /*
        Description:
        Parameters:
        Return:
    */
    include_once('../includes/config.inc.php');
    include_once('../includes/dbConnection.php');

    // $newTargetID = (isset($_GET['newTargetID']) && $_GET['newTargetID'] != '') ? strip_tags($_GET['newTargetID']) : null;
    // $service = (isset($_GET['service']) && $_GET['service'] != '') ? strip_tags($_GET['service']) : null;

    $newTargetID = "12988";
    $service = "16468";

    $returnValue = "0";

    if($newTargetID != null && $service != null){
        $ServiceReplicationQuery = "call ServiceReplication(" . $newTargetID . "," . $service . ")";
        error_log("ServiceReplicationQuery: " . $ServiceReplicationQuery);
        if($result = $dbConnection->query($ServiceReplicationQuery)){
            error_log("Successfully replicated service " . $service . " to target " . $newTargetID . ".");
            $returnValue = "1";
            $result->close();
        }
        else{
            error_log("Failure replicating service " . $service . " to target " . $newTargetID . ".");
        }
    }
    else{
        error_log("Failure replicating service " . $service . " to target " . $newTargetID . ".");
    }

    echo $returnValue;
?>

Note that the dbConnection.php include does have a valid and working mysqli db connection, and I have other AJAX back ends that are almost identical to this that work perfectly, the only difference is that I am using a stored procedure with this piece of code.

I can take the error_log echo of my query, place it in MySQL Workbench, and it works fine. In fact, even though I get this error, the database is updated. I am just getting this error and not getting the return value I need, which is "1".

Answer 1

You are erroneously setting a variable instead of comparing it in an if statement:

if ($result = $dbConnection->query($ServiceReplicationQuery)) {

This will always evaluate to true. The error you get is because you try to call method close() on $result, which is fatal when $result is not an object.

Update your code to this instead of $result->close() :

$dbConnection->close();

Or if you really want to call close on $result:

$result = $dbConnection->query($ServiceReplicationQuery)
if ($result) {

or this:

$result = $dbConnection->query($ServiceReplicationQuery)
if (is_object($result)) {

depending on what is more appropriate in what you are trying to accomplish.