Exception::getPrevious

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

Exception::getPreviousReturns previous Throwable

Description

final public Exception::getPrevious(): ?Throwable

Returns previous Throwable (which had been passed as the third parameter of Exception::__construct()).

Parameters

This function has no parameters.

Return Values

Returns the previous Throwable if available or null otherwise.

Examples

Example #1 Exception::getPrevious() example

Looping over, and printing out, exception trace.

<?php
class MyCustomException extends Exception {}

function
doStuff() {
try {
throw new
InvalidArgumentException("You are doing it wrong!", 112);
} catch(
Exception $e) {
throw new
MyCustomException("Something happened", 911, $e);
}
}


try {
doStuff();
} catch(
Exception $e) {
do {
printf("%s:%d %s (%d) [%s]\n", $e->getFile(), $e->getLine(), $e->getMessage(), $e->getCode(), get_class($e));
} while(
$e = $e->getPrevious());
}
?>

The above example will output something similar to:

/home/bjori/ex.php:8 Something happened (911) [MyCustomException]
/home/bjori/ex.php:6 You are doing it wrong! (112) [InvalidArgumentException]

See Also

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User Contributed Notes 2 notes

up
8
harry at upmind dot com
6 years ago
/**
     * Gets sequential array of all previously-chained errors
     *
     * @param Throwable $error
     *
     * @return Throwable[]
     */
    function getChain(Throwable $error) : array
    {
        $chain = [];

        do {
            $chain[] = $error;
        } while ($error = $error->getPrevious());

        return $chain;
    }
up
-6
Anonymous
13 years ago
May be I am late (5.2 is not supported). But if you want use the functionality of "previous Exception" in PHP < 5.3 or write compatible code, you can use next way as below.

<?php
abstract class App_Exception_PreviousNativeAbstract extends Exception {
    public static
$printPrevious = true;

    public function
__toString() {
       
$result   = array();
       
$result[] = sprintf("Exception '%s' with message '(%s) %s' in %s:%d", get_class($this), $this->code, $this->message, $this->file, $this->line);
       
$result[] = '---[Stack trace]:';
       
$result[] = $this->getTraceAsString();

        if (
self::$printPrevious) {
           
$previous = $this->getPrevious();
            if (
$previous) {
                do {
                   
$result[] = '---[Previous exception]:';
                   
$result[] = sprintf("Exception '%s' with message '(%s) %s' in %s:%d", get_class($previous), $previous->getCode(), $previous->getMessage(), $previous->getFile(), $previous->getLine());
                   
$result[] = '---[Stack trace]:';
                   
$result[] = $previous->getTraceAsString();
                } while(
method_exists($previous, 'getPrevious') && ($previous = $previous->getPrevious()));
            }
        }

        return
implode("\r\n", $result);
    }
}

abstract class
App_Exception_PreviousLegacyAbstract extends App_Exception_PreviousNativeAbstract {
    protected
$previous;

    public function
__construct($message, $code = 0, Exception $previous = null) {
       
$this->previous = $previous;

       
parent::__construct($message, $code);
    }

    public function
getPrevious() {
        return
$this->previous;
    }
}

if (
version_compare(PHP_VERSION, '5.3.0', '>=')) {
    abstract class
App_Exception_PreviousAbstract extends App_Exception_PreviousNativeAbstract {}
}
else {
    abstract class
App_Exception_PreviousAbstract extends App_Exception_PreviousLegacyAbstract {}
}

class
App_Exception extends App_Exception_PreviousAbstract {
    public function
__construct($message, $code = 0, Exception $previous = null) {
       
parent::__construct($message, 0, $previous);
    }
}

// Example:
try {
   
// ...
   
throw new Exception('Exception mesage');
   
// ...
} catch (Exception $e) {
    throw new
App_Exception('App exception mesage', 0, $e);
}
?>
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