Framework Hooks

Introduction

Getting Started

Exception Hooks

The Exception Hook is fired when an exception is thrown in an application. Anytime you would normally see the debug view when developing is when this hook will fire. This hook may not be fired if the server does not boot up because of an exception depending on how far into the container the exception is thrown but any normal application exceptions encountered will fire this hook.

The exception hook to tie into is ExceptionHook. This means that the key in the container should end with ExceptionHook and Masonite will call it when the Exception Hook is thrown. We can load things into the container such as:

app.bind('SentryExceptionHook', YourObject())

Notice here that our key ends with ExceptionHook and that we instantiated the object. Let's explore creating this entirly from scratch.

Creating A Hook

Let's create a class called SentryHook and put it into app/hooks/sentry.py.

class SentryHook:
    def __init__(self):
        pass
    
    def load(self, app):
        self._app = app

This should be the basic structure for a hook. All hooks require a load method. This load method will always be passed the application container so it always requires that parameter. From here we can do whatever we need to by making objects from the container.

But for this example we actually don't need the container so we can ignore it.

Adding Sentry

This should be the finished hook:

from raven import Client
client = Client( 'https://874..:j8d@sentry.io/1234567')

class SentryHook:
    def __init__(self):
        pass
    
    def load(self, app):
        client.captureException()

Tieing Into The Exception Hook

Now let's walk through how we can simply tie this into the container so it will be called when an exception is thrown in our project.

We can create a new Service Provider to store our hooks so let's make one.

$ craft provider HookProvider

This will create a new Service Provider inside app/providers/HookProvider.py that looks like:

from masonite.provider import ServiceProvider

class SentryServiceProvider(ServiceProvider):
    def register(self): 
        pass

    def boot(self): 
        pass

Now let's just add our hook to it:

from masonite.provider import ServiceProvider
from ..hooks.sentry import SentryHook

class SentryServiceProvider(ServiceProvider):
    def register(self): 
        self.app.bind('SentryExceptionHook', SentryHook())

    def boot(self): 
        pass

And finally add the Service Provider to our PROVIDERS constant in our config/application.py file:

...
# Application Providers 
'app.providers.UserModelProvider.UserModelProvider',
'app.providers.MiddlewareProvider.MiddlewareProvider',

# Sentry Provider
'app.providers.SentryServiceProvider.SentryServiceProvider',
...