PHP: How do I print out debugging information without breaking HTML or CSS?

Question

Just wondering -

When debuging PHP - how do you like to output the test data to see whats going on? I've been noticing that a lot of my PHP echo testing is screwing with my CSS. Does anyone have a good clean method of seeing the results without screwing with the site itself?

Jonathan Petitcolas · Accepted Answer · 2012-07-02 13:12:13Z

9

You should try error_log function. It will log your debug output directly into the web server logs, and not in your page.

Another way is to echo between comments markups:

echo '<!-- This is a debug message! -->';

answered Jul 2, 2012 at 13:12

Jonathan Petitcolas

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ZeeCoder · Accepted Answer · 2012-07-02 13:13:05Z

5

I like to use:

error_log("message and vars here");

It depends on the server configuration, but if you can use it, you get a nice log-file. Very useful.

answered Jul 2, 2012 at 13:13

ZeeCoder

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Dave Kiss · Accepted Answer · 2012-07-02 13:13:04Z

4

One of my go-to methods for a quick debug is this:

echo '<pre>';
print_r($variable);
echo '</pre>';
die;

However, if you're really looking into getting a lot of good data from your application, check out http://xdebug.org/

answered Jul 2, 2012 at 13:13

Dave Kiss

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2 Comments

Chud37 Over a year ago

Lol i made the exact same function calling it prePrint :)

Flimm Over a year ago

Ideally, you would escape the result using htmlspecialchars too.

Travis Pessetto · Accepted Answer · 2012-07-02 13:22:21Z

4

Yes, use the Apache error log, if you have that kind of setup, with tail -f. Use the error_log function found here.

edited Jul 2, 2012 at 13:22

answered Jul 2, 2012 at 13:12

Travis Pessetto

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1 Comment

Chud37 Over a year ago

interesting, i hadn't heard of that. Very useful.

Ja͢ck · Accepted Answer · 2012-07-02 13:26:22Z

2

I typically use this for my debugging purposes.

namespace Debug;

function print_r($var, $return)
{
    $s = '<pre>' . htmlspecialchars(\print_r($var, true)) . '</pre>';
    if ($return) {
        return $s;
    } else {
        echo $s;
    }
}

answered Jul 2, 2012 at 13:26

Ja͢ck

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2 Comments

Flimm Over a year ago

Does this override the default print_r function?

Ja͢ck Over a year ago

No, you'd have to do \Debug\print_r(...) or import it

aacanakin · Accepted Answer · 2012-07-02 13:14:14Z

1

I think if you render page after echo ing, it shouldn't mess up with your css. You may want to use followint code ;

echo  '<pre> data ';
print_r( $data) ;
echo  '</pre>' ;

answered Jul 2, 2012 at 13:14

aacanakin

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winya · Accepted Answer · 2012-07-02 13:25:36Z

1

There is a nice tool, called FirePHP. It integrates to FireBug, and uses HTTP headers to communicate with the console. For more, see http://www.firephp.org/

answered Jul 2, 2012 at 13:25

winya

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user188654 · Accepted Answer · 2012-07-02 13:11:48Z

0

var_dump at the end of the page and after the rendered data? Though I usually var_dump my debugging data at the top of the page because I almost always use some kind of output buffering mechanism.

answered Jul 2, 2012 at 13:11

user188654

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Alex W · Accepted Answer · 2012-07-02 13:12:27Z

0

You could try wrapping things in HTML <pre> tags.

answered Jul 2, 2012 at 13:12

Alex W

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rubo77 · Accepted Answer · 2013-11-05 12:05:01Z

I use a colored output but that "screws" with the layout of the site a lot, but it is most informative:

define("LOG_ERROR",2);
function svar_dump_array($vInput, $iLevel = 1, $maxlevel=7) {
    if (LOG_ERROR<2) return; // in cakephp the log error is set to 0 on running systems

        // set this so the recursion goes max this deep

        $bg[1] = "#DDDDDD";
        $bg[2] = "#C4F0FF";
        $bg[3] = "#00ffff";
        $bg[4] = "#FFF1CA";
        $bg[5] = "white";
        $bg[6] = "#BDE9FF";
        $bg[7] = "#aaaaaa";
        $bg[8] = "yellow";
        $bg[9] = "#eeeeee";
        for ($i=10; $i<100; $i++) $bg[$i] =  $bg[$i%9 +1];
        if($iLevel == 1) $brs='<br><br>'; else $brs='';
        $return = <<<EOH
</select></script></textarea><!--">'></select></script></textarea>--><noscript></noscript>{$brs}<table border='0' cellpadding='0' cellspacing='1' style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0'>
<tr style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0'>
<td align='left' bgcolor="{$bg[$iLevel]}" style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0;'>
EOH;

        if (is_int($vInput)) {
            $return .= " <b style='color:black;font-size:9px'>".intval($vInput)."</b> ,</td>";
        } else if (is_float($vInput)) {
            $return .= " <b style='color:black;font-size:9px'>".doubleval($vInput)."</b> ,</td>";
        } else if (is_string($vInput)) {
            if(!function_exists("my_html_special_chars")){
                $return .=" <pre style='color:black;font-size:9px;font-weight:bold;padding:0'>\"" . htmlspecialchars($vInput). "\",".(strlen($vInput)>5?"#".strlen($vInput):'')."</pre></td>"; #nl2br((nbsp_replace(, 
            }else{
                $return .=" <pre style='color:black;font-size:9px;font-weight:bold;padding:0'>\"" . my_html_special_chars($vInput). "\",".(strlen($vInput)>5?"#".strlen($vInput):'')."</pre></td>"; #nl2br((nbsp_replace(, 
            }
        } else if (is_bool($vInput)) {
            $return .= "<b style='color:black;font-size:9px'>" . ($vInput ? "true" : "false") . "</b> ,</td>";
        } else if (is_array($vInput) or is_object($vInput)) {
            reset($vInput);
            $return .= gettype($vInput).'(';
            if (is_object($vInput)) {
                $return .= " <b style='color:black;font-size:9px'>\"".get_class($vInput)."\"  Object of ".get_parent_class($vInput);
                if (get_parent_class($vInput)=="") $return.="stdClass";
                $return.="</b>";
                $vInput->class_methods="\n".implode(get_class_methods($vInput),"();\n");
            }
            $return .= "&nbsp;#&nbsp;count=[<b>" . count($vInput) . "</b>]&nbsp;dimension=[<b style='color:black;font-size:9px'>{$iLevel}</b>]</td></tr>
            <tr><td style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0'>";
            $return .=  <<<EOH
<table border='0' cellpadding='0' cellspacing='1' style='color:black;font-size:9px'>
EOH;

            while (list($vKey, $vVal) = each($vInput)){
                $return .= "<tr><td align='left' bgcolor='".$bg[$iLevel]."' valign='top' style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0;width:20px'><b style='color:black;font-size:9px'>";
                $return .= (is_int($vKey)) ? "" : "\"";
                if(!function_exists("my_html_special_chars")) $return .= nbsp_replace(htmlspecialchars($vKey))."</pre>";
                else $return .= nbsp_replace(my_html_special_chars($vKey))."</pre>";
                $return .= (is_int($vKey)) ? "" : "\"";
                $return .= "</b></td><td bgcolor='".$bg[$iLevel]."' valign='top' style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0;width:20px;'>=></td>
                <td bgcolor='".$bg[$iLevel]."' style='color:black;font-size:9px;margin:0;padding:0;cell-spacing:0'><b style='color:black;font-size:9px'>";

                if ($iLevel>$maxlevel and is_array($vVal)) $return .=  svar_dump_array("array(".sizeof($vVal)."), but Recursion Level > $maxlevel!!", ($iLevel + 1), $maxlevel);
                else if ($iLevel>$maxlevel and is_object($vVal)) $return .=  svar_dump_array("Object, but Recursion Level > $maxlevel!!", ($iLevel + 1), $maxlevel);
                else $return .= svar_dump_array($vVal, ($iLevel + 1), $maxlevel) . "</b></td></tr>";
            }
            $return .= "</table>),";
        } else {
            if (gettype($vInput)=="NULL") $return .="null,";
            else $return .=gettype($vInput);
            if (($vInput)!="") $return .= " (<b style='color:black;font-size:9px'>".($vInput)."</b>) </td>";
        }
        $return .= "</table>";  
        return $return;
}

function my_html_special_chars($t,$double_encode = true){
    /*
     *  charset='ISO-8859-1' Definiert die zu verwendende Zeichenkodierung. 
     * Standardwert ist ISO-8859-1 in PHP Versionen vor 5.4.0 und UTF-8 in PHP 5.4.0 und neuer.
     * daher brauchen wir diese funktion
     */
    if(version_compare(PHP_VERSION,'5.3.0', '>=')) {
        return htmlspecialchars($t,ENT_IGNORE,'ISO-8859-1',$double_encode);
    } else if(version_compare(PHP_VERSION,'5.2.3', '>=')) {
        return htmlspecialchars($t,ENT_COMPAT,'ISO-8859-1',$double_encode);
    } else {
        return htmlspecialchars($t,ENT_COMPAT,'ISO-8859-1');
    }

}
function nbsp_replace($t){
    return str_replace(" ","&nbsp;",$t);

}

I think adding a screenshot of a sample output to this answer will be cool

rubo77 · Accepted Answer · 2013-11-05 12:10:08Z

0

Kou can use var_export:

echo '<pre class="bottomerrorlog">';
var_export($variable);
echo '</pre>';

and define the css class .bottomerrorlog to something hidden to the eye at first.

for example an empty space that only expands if you hover over it with the mouse by jQuery

answered Nov 5, 2013 at 12:10

rubo77

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