How do I dump variables in Yii for debugging? - php

Question

How do I dump and print variables in Yii for debugging? I would like to use var_dump() or print_r(). I tried to use Yii::trace() but it crashes with this error in runtime/logs/app.log. It doesn't even tell me the line in my code that it fails.
2015-03-18 20:54:11 [::1][-][-][warning][yii\log\Dispatcher::dispatch] Unable to send log via yii\debug\LogTarget: Exception 'Exception' with message 'Serialization of 'SimpleXMLElement' is not allowed'
in /cygdrive/c/Users/Chloe/workspace/AffiliateArbitrage/vendor/yiisoft/yii2-debug/LogTarget.php:58
Stack trace:
#0 /cygdrive/c/Users/Chloe/workspace/AffiliateArbitrage/vendor/yiisoft/yii2-debug/LogTarget.php(58): serialize(Array)
#1 /cygdrive/c/Users/Chloe/workspace/AffiliateArbitrage/vendor/yiisoft/yii2-debug/LogTarget.php(112): yii\debug\LogTarget->export(Array)
#2 /cygdrive/c/Users/Chloe/workspace/AffiliateArbitrage/vendor/yiisoft/yii2/log/Dispatcher.php(183): yii\debug\LogTarget->collect(Array, true)
#3 /cygdrive/c/Users/Chloe/workspace/AffiliateArbitrage/vendor/yiisoft/yii2/log/Logger.php(170): yii\log\Dispatcher->dispatch(Array, true)
#4 [internal function]: yii\log\Logger->flush(true)
#5 {main}
Reference
http://www.yiiframework.com/doc-2.0/guide-runtime-logging.html

Answer 1

Because you are asking about something like var_dump and print_r, I can advise built-in helper for this. It's called yii\helpers\VarDumper. Yii::trace() is for logging trace messages.
VarDumper is intended to replace the buggy PHP function var_dump and print_r.
It can correctly identify the recursively referenced objects in a
complex object structure. It also has a recursive depth control to
avoid indefinite recursive display of some peculiar variables.
VarDumper can be used as follows,
VarDumper::dump($var);
Personally I don't use it, just tried only couple of times for testing.
I think is better to use Xdebug for that purposes.
See also PsySH.

Answer 2

Use this:
<?php echo '<pre>'; print_r($model); exit; ?>

Answer 3

I used this, but I'm sure there's a better way.
Yii::warning('**********************', var_export($category,true));
config/web.php
'log' => [
...
'flushInterval' => 1, // for debug
'targets' => [
[
...
'exportInterval' => 1, // for debug - slow
],
],
],

Answer 4

Use this, to see your variable or object array.
use yii\helpers\VarDumper;
VarDumper::dump($variableArray , $dept = 10, $highlight = true);
To detail you can read the doc
http://www.yiiframework.com/doc-2.0/yii-helpers-basevardumper.html#dump()-detail

Answer 5

You can do it yourself:
In your main index page (back/index.php or front/index.php) add this code to the top ob_start();. Then define 2 functions for better debugging
function dd($v){
ob_clean();
var_dump($v);
exit;
}
function dj($v){
ob_clean();
echo CJSON::encode($v);
exit;
}
and add ob_end_flush(); at the very end of your main index page . Now you can call dd($model) or dj($model). There you had your dumper working. Congratulations!

Answer 6

I had written an article about this problem with debug variables in Yii 2:
Since for the sake of Simplicity and Quick Development, I’ve created a helper for those who use Yii. You can just call dd($var1, $var2, ….); for dump & die or d($var1, $var2, ….); for dump data.
Details and installation instructions are on: https://dangnhsite.wordpress.com/2016/04/06/variable-debug-in-yii-2/