Debugging in CodeIgniter (and MVC) - php

Question

Often times I feel the need to dump a variable for debugging purpose. In CodeIgniter I am struggling to do that since I cannot simply "echo" a variable without passing it to the view first, which I think is pain-staking. I have read the official documentation, though I had found a good solution with the log_message function but cannot make it work, even though I successfully made the "logs" folder writable and changed the "threshold" as advised. Any suggestions?
https://www.codeigniter.com/user_guide/general/errors.html

Answer 1

It's not good practice, but you can output anything to the browser at any point in execution (from core classes, libraries, models and controllers) by simply using print_r() at the point you want to output the info.
Of course, this will sometimes not display as there may be redirects/routes/etc that take the user to the next step in the controller execution, but if you want to suppress this (again, for debug purposes only), you can use:
print_r($string_or_variable_to_debug);
die();
The die() command will stop all execution and leave you with just the info you want to output.
Using log_message() is better practice, but it's difficult to understand why you're not having success there if you say you've followed the following steps:
Make sure that your logs folder is set to be writable
Set $config['log_threshold'] to 2, 3 or 4
Used the function like so: log_message('debug','Message you want to log');
If you want to use print_r() to nicely format an array or object inside the log message, then you'll need to set the second parameter of print_r() to TRUE, like so:
log_message('debug',print_r($array_or_object,TRUE));

Answer 2

You need to set your $config['log_threshold'] in file config.php since by default it's 0 (no logs)
0 = Disables logging, Error logging TURNED OFF
1 = Error Messages (including PHP errors)
2 = Debug Messages
3 = Informational Messages
4 = All Messages

Answer 3

I think the answer is you are looking for is:
Codeigniter - Developer's Debug Helper
You can add this file to application/helper folder. Then autoload vayes_helper in application/config/autoload.php for generic use. Then all you need to is writing:
vdebug($variable); // In Controllers, Models, Libraries, Helpers
<?=vdebug($variable)?> // In View files

Answer 4

log_message('debug',print_r($array_or_object_you_want_to_print,TRUE));
This will print your array nicely into log . Following is the output example :
[1] => Array
(
[uid] => 10049082
[phone_id] => 2
[friend_status] => 0
[friend_event_hide_status] =>
)
[2] => Array
(
[uid] => 10042768
[phone_id] => 4
[friend_status] => 3
)
[3] => Array
(
[uid] => 10078255
[phone_id] => 6
[friend_status] => 2
)
[4] => Array
(
[uid] => 10078255
[phone_id] => -1
[friend_status] => 1
[name] => Rajesh
)
[5] => Array
(
[uid] => 10078255
[phone_id] => -1
[friend_status] => 1
[name] => ritesh kumar
)
[6] => Array
(
[uid] => 10078255
[phone_id] => -1
[friend_status] => 1
[name] => Le
)