How do I dump variables in Yii for debugging?

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

Solution 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.

Solution 2

Use this:

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

Solution 3

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

Solution 4

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
            ],
        ],
    ],

Solution 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!

View more solutions

Comments

[Chloe]

Perfect! Old school debugging! Except that stupid default nav bar floating at the top that obscures the output...

[arogachev]

Add exit or die right after dump the same as with regular var_dump and print_r.

[arogachev]

Added link to another debugger that probably will help you more with this.

[Chloe]

Psy SH looks really neat but there's probably something wrong with it. Composer didn't install any executable. Not only that, it's not clear how to connect the shell to the web server. It says it will drop into a shell if you add the debug line, but PHP is running in Apache in the background! How will it show a shell? There's no mention of setting a port or anything for remote debugging.

[user7866688]

echo '<pre>'; print_r($model); exit; Tnks

[user7866688]

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

[Fabio says Reinstate Monica]

Hello, welcome to SO. If you realize you have forgotten something, or made a mistake, you should edit your answer, not leave it as a comment. Comments are not read by all, they could be deleted, and do not allow proper code formatting. Another user has already suggested an edit to fix it: please review it, edit your answer further if you think it's needed, and then remove the comments. Thank you!

[Roby Sottini]

Where can I see the message?

[Amil Waduwawara]

Actually I wanted to see messages almost immediately in log files for Yii commands. This helped me, thanks a lot