PHP Attempting to invoke a serialized / encoded anonymous function within a class method returns 'Method name must be a string'

Question

I have a class within which I want to

Set an array
Loop through the array
Invoke anonymous functions set in #1 as I loop through the array in #2

EDIT: The code below is working when tested out of my application, but in my CodeIgniter 3 Controller, I keep getting an error: Method name must be a string

My simplified code for the purposes of example (CodeIgniter 3):

<?php

class MyClass {

    // Setting my array
    public function my_arr ($options = array())
    {
        $arr = array(
            '1' => array(
                'a' => 'z',
                'b' => function($i) {
                    return 'c' . $i;
                },
            ),
            '2' => array(
                'a' => 'y',
                'b' => function($i) {
                    return 'd' . $i;
                },
            ),
        );

        return $arr;
        /**
         *
         * EDIT: Later in my code I found that there was some kind
         * of serialization/encoding attempt like:              
         * json_decode(json_encode($arr));
         */

    }

    // Doing My Loop
    public function do_loop()
    {
        $my_arr = $this->my_arr();
        $i = 0;
        foreach($my_arr as $key => $value){
            $anonymous_function = $value['b'];
            echo $anonymous_function($i) . '<br>'; // Keep getting `Method name must be a string`
            $i++;
        }
    }

}

(new MyClass())->do_loop();

This code should never enter the loop at all, `my_arr()` doesn't return anything here. It also has invalid syntax. In this particular case you should provide with an example that is reproducible. Fixing those two issues I can't reproduce your problem at https://3v4l.org/2vLRs — apokryfos, Sep 04 '22 at 22:03
I still cannot reproduce your problem https://onlinephp.io/c/2e92c — apokryfos, Sep 05 '22 at 05:48
Thanks again @apokryfos . After a bit more digging, I found that the issue had to do with serialization / encoding. I've updated my original question & title for clarity. — Ryan Dorn, Sep 05 '22 at 10:18

Ryan Dorn · Answer 1 · 2022-09-05T10:19:53.113

Posting back here in hopes that it helps.

My issue:

Later on in my codebase, I was trying to encode/serialize my method's output.
After a bit of reading, I found out that json_encode() & serialize() don't support serialization of closures / anonymous functions.
So, the Method name must be a string error happend because my attempts to encode/serialize - effectively - stripped the anonymous functions out & thus referenced a null function.

How I resolved the issue:

First I started with Opis Closure library to seralize the closure (I didn't end up going with this, but including it because I think it's a pretty cool library)
After the above, I just realized that I should refactor so that I wasn't trying serialize closures at all.

PHP Attempting to invoke a serialized / encoded anonymous function within a class method returns 'Method name must be a string'

1 Answers1