The JsWebApp Object

The core JsWebApp class that ties everything together. It's responsible for routing, configuration, middleware, and handling the WSGI application lifecycle.

Initialization

You create an instance of JsWebApp by passing a configuration object.

# app.py
import config
from jsweb.app import JsWebApp

app = JsWebApp(config=config)

Routing

The @app.route() decorator is used to associate a view function with a URL path and HTTP methods.

@app.route('/')
def home(req, res):
    return "Hello, World!"

@app.route('/users/<int:user_id>', methods=['GET', 'POST'])
def user_profile(req, res, user_id):
    # ...

Registering Blueprints

Use the register_blueprint() method to mount a blueprint onto the application.

from my_module.views import my_blueprint
app.register_blueprint(my_blueprint)

Template Filters

You can add custom filters to the Jinja2 template environment using the @app.filter() decorator.

@app.filter('uppercase')
def to_uppercase(value):
    return str(value).upper()

In your template:

{{ my_variable|uppercase }}

Middleware

JsWeb automatically applies a chain of middleware to every request. The order is important:

1. CSRFMiddleware: Protects against Cross-Site Request Forgery.
2. StaticFilesMiddleware: Serves static files from the configured directory.
3. DBSessionMiddleware: Manages the SQLAlchemy database session lifecycle.

This is handled internally within the __call__ method of the JsWebApp instance.