php debug code example

Example 1: how to debug in php

ini_set('display_errors', 'On');
error_reporting(E_ALL);

Example 2: php best debugging functions

I find it very useful to print out to the browsers console instead of just var_dumping:

function console_log( $data ){
  echo '<script>';
  echo 'console.log('. json_encode( $data ) .')';
  echo '</script>';
}

Usage:
$myvar = array(1,2,3);
console_log( $myvar ); // [1,2,3]

Example 3: php best debugging functions

A good example of data output to the console via <script> tags, I myself used this first, but he broke the captcha job, because <script> tags were inserted into the base64 code of the captcha picture. Then I began to display logs in the headers with such a function (it may help someone else, in a similar situation):

<?php

function header_log($data){
  $bt = debug_backtrace();
  $caller = array_shift($bt);
  $line = $caller['line'];
  $file = array_pop(explode('/', $caller['file']));
  header('log_'.$file.'_'.$caller['line'].': '.json_encode($data));
}

?>

Usage:
$myvar = array(1,2,3);
header_log( $myvar ); // in headers we see: log_filename_rownumber: [1,2,3]

Example 4: debug php

// ------ string -------
// use echo, exit for output
$a = 123
echo ($a);
exit;


// ------ array -------
$array = array(
	1 => 'apple',
  	2 => 'banana',
)

// Method 1
echo "<pre>";
print_r($array);
echo "</pre>";

// Method 2 
echo "<pre>";
var_dump($array);
echo "</pre>";

// Method 3 (no need exit) beacause of dd is already exit
dd($array)
  
// Method 4 (cakephp)
pr ($array);


// ------ json -------
$json = {"a":"123"}

pr (json_encode($json));
exit;

print_r (json_encode($json));
exit;