How can I track errors from a called function?

tony · 08-17-2008, 09:14 PM

I am not sure if this goes here but I am kinda beginning with PHP so I put it here, even though it might be a problem in a different level.

My problem is that i made a static query class to have more security in queries before sending them. But i want to know if there is an error in the query to tell me on which file on what line, the query method was called. like this:

PHP Code:


			
<?php

class QUERY{

#properties

public static $Result;



#Queries

static function select($columns, $table, $fit=NULL, $match=NULL)

{

//make sure parameters are right type

(!is_string($table))? return false;

(!is_array($columns) || !is_string($columns))? return false;

(!is_string($fit) || !is_null($fit))? return false;

(!is_string($match) || !is_null($match))? return false;



(is_string($columns)? $columns=explode(”:”,$columns);



//security door

$table=quoteSmart($table);

$columns=quoteSmartArray($columns);

($fit!=NULL)? $fit=quoteSmart($fit);

($match!=NULL)? $match=quoteSmart($match);



//make a safe query

$query = sprintf(

(!is_array($columns)) return false;“SELECT %s FROM %s”,

implode(”, ”, $columns), $table);



if(!$fit==NULL && !$match==NULL)

$query .= sprintf(” WHERE %s=%s”, $fit, $match)



$sql=mysql_query($query); unset($query);

self::$Result=array();

while($row=mysql_fetch_assoc($sql)

or throw new Exception(“Error in Line 36 in Query class ”.mysql_error()))

{

for($i=0; $i<count($res);$i++)

{

foreach($row as $key => $value)

self::$Result[$i][$key]=$value;

}

}



return self::$Result;

}

}

?>

then in another file i can make a called like this:

PHP Code:


			
<?php

$res=QUERY::select(‘CommentID:UserID:Text:DateTime:MediaID’,

‘comments’, ‘CommentID’, $id);



$ID=$res[0][‘CommentID’];

$UserID=$res[0][‘UserID’];

$MediaID=$res[0][‘MediaID’];

$Comment=$res[0][‘Comment’];

$Date=$res[0][‘DateTime’];

?>

as you can see the error is sent and gives me the error line of the query method instead of giving the the line and file where it was called. and I am trying to find a way of telling me that, but i haven’t and it’s frustrating me.
any advice or tips?

Kalle · 08-18-2008, 02:27 AM

Take a look at the function called debug_backtrace() and debug_print_backtrace() in your error handlers:

PHP: debug_print_backtrace - Manual
PHP: debug_backtrace - Manual

tony · 08-18-2008, 04:18 AM

Oh they keep track of all the calls. That is more handy then the mess I've been trying to get. I'm going to incorporate it in the script and post the results, thanks.

xenon · 08-18-2008, 07:04 PM

Or, there is also the Reflection class (php 5+). It provides you waaay more info than that little function.

delayedinsanity · 08-18-2008, 08:04 PM

php 5.1.3 and above, to be exact, as I found out just recently.

*lurvs Reflection*

tony · 08-18-2008, 08:19 PM

wow, i should have read the whole oop section. this is good stuff. going to look at it.
Thanks

Kalle · 08-18-2008, 09:28 PM

Quote:

Originally Posted by xenon

Or, there is also the Reflection class (php 5+). It provides you waaay more info than that little function.

Reflection does not provide the information he want in this case because it does not provide a stack trace like debug_backtrace().

Combining a custom error handler set though set_error_handler() with debug_backtrace() makes it possible to show where the error occured where Reflection only can be used to extend the information from debug_backtrace() =)

(That is if I understand his problem correctly ofcourse)

delayedinsanity · 08-18-2008, 11:39 PM

No Kalle. You are not allowed to speak of such things. Reflection can do anything. ANYTHING.

xenon · 08-19-2008, 12:22 AM

Quote:

Originally Posted by Kalle

Reflection does not provide the information he want in this case because it does not provide a stack trace like debug_backtrace().

Oh yes, it does. You just don't know about it :P

Try the getTrace method for an array containg all the trace info you need, and format it as you need, or, use the built-in getTraceAsString method, to get a default trace format. You can, of course, use something like this on the output:

PHP Code:


			
try
{
    // ...
}
catch(Exception $e)
{
    echo str_replace("\n", '<br />', $e->getTraceAsString());
}

to get a perfectly readable and displayable HTML form of the stack trace. Awesome, right? :D

The advantage of the exceptions is that you don't need to log the line on which an exception occured, nor the file in which the source code of the function/method was located. The exceptional engine keeps in mind all that stuff (and this is just the beginning of it) :) All you need to do is nicely ask for it.

Kalle · 08-19-2008, 10:55 AM

Quote:

Originally Posted by xenon

Oh yes, it does. You just don't know about it :P

Try the getTrace method for an array containg all the trace info you need, and format it as you need, or, use the built-in getTraceAsString method, to get a default trace format. You can, of course, use something like this on the output:

PHP Code:


			
try

{

    // ...

}

catch(Exception $e)

{

    echo str_replace("\n", '<br />', $e->getTraceAsString());

}

to get a perfectly readable and displayable HTML form of the stack trace. Awesome, right? :D

The advantage of the exceptions is that you don't need to log the line on which an exception occured, nor the file in which the source code of the function/method was located. The exceptional engine keeps in mind all that stuff (and this is just the beginning of it) :) All you need to do is nicely ask for it.

Then its not Reflection, but Exceptions =)

xenon · 08-19-2008, 07:34 PM

Exceptional code (to be read code that throws exceptions) + reflection = the greatest debugging tool ever (and even documentation, why not). As someone said already, you can do just about anything with reflection.

Salathe · 08-19-2008, 08:02 PM

Quote:

Originally Posted by xenon

As someone said already, you can do just about anything with reflection.

Except slice my bread. I wish someone would invent a tool to do that!

xenon · 08-19-2008, 09:36 PM

Except that, of course. And going to work instead of you. That's reflection weak points. But I'm sure the guys over at php.net work hardly on these issues

Kalle · 08-19-2008, 10:34 PM

Quote:

Originally Posted by xenon

Except that, of course. And going to work instead of you. That's reflection weak points. But I'm sure the guys over at php.net work hardly on these issues

Well you will be glad to hear that Reflection has got some new methods to play around with in 5.3, most of the work atm at php.net is going towards the 5.3 release :)