Service Providers

Service Providers

Introduction

Service Providers are the key building blocks to Masonite. The only thing they do is register things into the Service Container, or retrieve things from the Service Container. You can read more about the Service Container in the Service Container documentation. If you look inside the config/providers.py file, you will find a PROVIDERS list which contains all the Service Providers involved in building the framework.

You may create your own service provider and add it to your providers list to extend Masonite, or even remove some providers if you don't need their functionality. If you do create your own Service Provider, consider making it available on PyPi so others can install it into their framework.

Creating a Provider

We can create a Service Provider by simply using a craft command:

$ python craft provider DashboardProvider

This will create a new Service Provider under our app/providers/DashboardProvider.py. This new Service Provider will have two simple methods, a register method and a boot method. We'll explain both in detail.

Service Provider Execution

There are a few architectural examples we will walk through to get you familiar with how Service Providers work under the hood. Let's look at a simple provider and walk through it.

from masonite.provider import ServiceProvider
from app.User import User

class UserModelProvider(ServiceProvider):
    ''' Binds the User model into the Service Container '''

    wsgi = False 

    def register(self):
        self.app.bind('User', User)

    def boot(self):
        print(self.app.make('User'))

We can see that we have a simple provider that registers the User model into the container. There are three key features we have to go into detail here.

WSGI

First, the wsgi = False just tells Masonite that this specific provider does not need the WSGI server to be running. When the WSGI server first starts, it will execute all service providers that have wsgi set to False. Whenever a provider only binds things into the container and we don't need things like requests or routes, then consider setting wsgi to False. the ServiceProvider class we inherited from sets wsgi to True by default. Whenever wsgi is True then the service provider will fire the boot method on every request.

Register

In our register method, it's important that we only bind things into the container. When the server is booted, Masonite will execute all register methods on all service providers. This is so the boot method will have access to the entire container.

Boot

The boot method will have access to everything that is registered in the container and is actually resolved by the container. Because of this, we can actually rewrite our provider above as this:

from masonite.provider import ServiceProvider
from app.User import User

class UserModelProvider(ServiceProvider):
    ''' Binds the User model into the Service Container '''

    wsgi = False 

    def register(self):
        self.app.bind('User', User)

    def boot(self, user: User):
        print(user)

This will be exactly the same as above. Notice that the boot method is resolved by the container.

Provider Methods

Service providers have several methods we can use to help us bind objects into the container.

Commands

We can simply bind commands into the container:

def register(self):
    self.commands(Command1(), Command2())

Middleware

We can also bind http and route middleware into the container:

def register(self):
    self.http_middleware([Middleware, Here])
    self.route_middleware({'middleware': Here})

Notice that the route middleware accepts a dictionary and the http middleware accepts a list

Migrations

We can add directories that have migrations easily as well:

def register(self):
    self.migrations('directory/1', 'directory/2')

Routes

We can also add routes:

def register(self):
    self.routes([
        get(...),
    ])

Assets

We can also add any directories that have asset files:

def register(self):
    self.assets({'/directory': 'alias/'})

Great! It's really that simple. Just this knowledge will take you a long way. Take a look at the other service providers to get some inspiration on how you should create yours. Again, if you do create a Service Provider, consider making it available on PyPi so others can install it into their framework.