Question

I am about to start implementing error handling into my framework and looking for some advice on how to build it.

Firstly let me explain how my framework is currently built up:

Im separating the framework startup from the application startup, so any errors caused within the application startup should be handled specifically by a class dedicated to that.

My idea is to have a class called Core_Error_exception witch will set the error reporting to E_ALL as my framework will be strict on errors for PHP 5.3, then as my as my application load I will run a shutdown function function within that class to restore all default values changed.

What im looking to do is capture all errors that are E_*_NOTICE and not E_*_ERROR and then before the application starts I tell the class to stop capturing errors as the Application_Error_Exception will be watching out for errors.

So i will need a way to track all errors including exceptions and triggers and then before the application initializes show a framework debug page.

The kind of class I was looking for is like so:

class Core_Error_Exception
{
    var $previus_error_level,$captured_contents;

    private $stack_trace = array();

    public function Core_Error_Exception()
    {
        $this->previus_error_level = error_reporting(-1);
        set_error_handler(array($this,'_collect_error'));
        set_exception_handler(array($this,'_collect_error'));
        ob_start(array($this,'_capture'));
    }

    public function _collect_error($errno, $errstr, $errfile, $errline, $context)
    {
        $this->stack_trace[] = array(
            array('name' => 'Error ID:',    'value' => $errno),
            array('name' => 'Error String:','value' => $errstr),
            array('name' => 'Error File:',  'value' => $errfile),
            array('name' => 'Error Line:',  'value' => $errline),
            array('name' => 'Context PRE:', 'value' => $context)
        );
        var_dump($this->stack_trace);
    }

    /*
     * _capture is used to capture pre_bufferd content.
     */
    public function _capture($content,$bitfeild)
    {
        if($bitfeild & PHP_OUTPUT_HANDLER_START)
        {
            $this->captured_contents = $content;
        }

        if($bitfeild & PHP_OUTPUT_HANDLER_CONT)
        {
            $this->captured_contents .= $content;
        }

        if($bitfeild & PHP_OUTPUT_HANDLER_END)
        {
            $this->captured_contents .= $content;
        }
        return false;
    }
}

So what im looking to do is to be able to construct this class in a fall-proof way so that any notice errors that may have been triggered will be placed into an array, if an E_ERROR notice is called then this automatically run the shut-down at that point, to prevent more errors being caused.

I will be using a small html template handler where I can pass into that context sets of errors, so Notice errors and a single E_*_ERROR if applicable.

Whats the best way to build this class as in the past I have had some difficulty in doing Error Tracking / Reporting.

Updated: with current class

If errors are triggered such as trigger_error(‘test’,XXX); I want to be able to track all errors until the application launches or an E_USER_ERROR has been triggered.

Sometimes I struggle to fully grasp PHP’s error system, and so on as sometimes i get confused in how to build it so its fall-proof.

Answer 1

I’m not quite sure about what you’re doing, but the most straightforward way would be to use nested try blocks, along the lines of

in Class Application:

    function run() {
        try {
            --do stuff
        } catch(AppException $e) {
            -- handle application-level exception
        }
        -- all other exceptions fall through


in Class Core:

    try {
        $core->init();
        $application->run(); <-- calls the above function
        $core->done();
    } catch(Exception $e) {
        --last chance exception handler
        --process exceptions the Application was unable to handle on its own
    }

To be able to catch php built-in errors or trigger_error events this way, you also should always install an errors-to-exceptions handler.