Error handlers should respect outputBuffering setting

[akrabat]

Given this code,

$app->get("/", function ($request, $response, $args) {
    var_dump($request);
    throw new \Exception("oops");
});

I should see the var_dump'd information displayed if outputBufferring is set to append or prepend.

This requires changes to:

• Route::__invoke() to remove the ob_end_clean() calls.
• Pass the outputBuffering setting into Slim\Handlers\AbstracError's constructor and store as a protected property
• Update Slim\Hanlders\Error to use ob_get_clean() and add it to the response in the correct place as per the outputBuffering setting.

[akrabat]

Thinning about it, this is probably solvable with middleware.

[RyanNerd]

@akrabat Is this going to be "solved with middleware"?

I'm looking at issues tagged with 'help wanted' so I can possibly pitch in. I obviously don't want to work on something that doesn't need fixing...

[geggleto]

@akrabat this seems like a bug; I wouldn't want it fixed as a middleware.

@RyanNerd Let me know if you want to make a PR for this :)

[RyanNerd]

@geggleto I'll see if I can come up with a working PR in the next few days.

[pengu-fr]

I have a problem with this implementation...
Removing the ob_get_clean from the "catch(s)" of Route::__invoke() breaks the ob_levels, as Route::__invoke() start the OB, but never close it in case of error. If we don't use Slim's default errorHandler, we have to know/implement Slim outputBuffering setting again, and close the OB correctly if needed... and I don't think it should be implemented in the errorHandler

IMO it's not the error handler responsability to handle the output buffer started by the Router. It should not even know about the outputBuffering setting.