Introduction to Emmett

Emmett is a modern, fast, and lightweight web framework designed for building high-performance web applications. With its asynchronous nature, integrated tools, and modular structure, Emmett makes web development seamless and efficient. It is written in Python and focuses on developer productivity by offering clean APIs, rich features, and a flexible architecture.

In this post, we will explore some of the most useful APIs provided by the Emmett framework with code examples. Additionally, we’ll build a simple app to demonstrate how easily everything integrates.

Core Features of Emmett

• Asynchronous routing
• Integrated ORM (Object-Relational Mapping)
• WebSocket support
• Background task management
• Form handling and validation
• Modular and extensible structure

Getting Started

Before diving into the API examples, install Emmett using pip:

  pip install emmett

Routing Example

Routing is at the core of any web application. Here’s how to define routes in Emmett:

  from emmett import App, request

  app = App(__name__)

  @app.route("/")
  async def home():
      return "Welcome to Emmett!"

  @app.route("/hello/")
  async def greet(name):
      return f"Hello, {name}!"

Form Handling

Emmett makes it easy to work with forms and validates user input:

  from emmett import Form
  from emmett.validators import requires

  class SignupForm(Form):
      fields = [
          "username": requires(),
          "password": requires(),
          "email": requires()
      ]

  app = App(__name__)

  @app.route("/signup")
  async def signup():
      form = SignupForm()
      if form.accepted:
          return "Signup successful!"
      return dict(form=form)

Database Integration with TORM

Emmett’s integrated ORM (TORM) makes it simple to manage database models:

  from emmett.orm import Database, Model, Field

  db = Database(app, "sqlite://storage.db")

  class User(Model):
      tablename = "users"
      username = Field()
      email = Field()

  db.define_models(User)

  # Example query
  users = User.all().select()

WebSocket Example

With built-in WebSocket support, you can create real-time applications:

  from emmett.ws import WS

  ws = WS(app)

  @ws.route('/')
  async def websocket_endpoint(_):
      await _.send("Connected to WebSocket!")
      async for message in _.receive():
          await _.send(f"You sent: {message}")

Working with Background Tasks

You can define and execute background tasks effortlessly:

  from emmett import App

  app = App(__name__)

  @app.before_start
  async def prepare():
      print("Application setup complete")

  @app.task
  async def background_task():
      print("Background task running!")

Building a To-Do List App with Emmett

Here’s an example of a simple to-do list app built using Emmett’s features including routing, forms, and ORM:

  from emmett import App, Form
  from emmett.orm import Database, Model, Field

  app = App(__name__)
  db = Database(app, "sqlite://storage.db")

  class TodoItem(Model):
      tablename = "todo_items"
      title = Field()
      completed = Field.bool(default=False)

  db.define_models(TodoItem)

  class TodoForm(Form):
      fields = {"title": requires()}

  @app.route("/")
  async def index():
      form = TodoForm()
      items = TodoItem.all().select()
      if form.accepted:
          TodoItem.create(title=form.params.title)
      return dict(form=form, items=items)

  @app.route("/toggle/")
  async def toggle_item(id):
      item = TodoItem.get(id)
      item.update_record(completed=not item.completed)
      return "Item updated!"

Run the application and navigate your browser to the defined routes to see the app in action!

Conclusion

Emmett is an excellent framework that combines simplicity and power to handle everything from routing to real-time communication. Whether you’re building a small app or a large-scale application, Emmett’s rich set of features and APIs make it a stellar choice. Start exploring its capabilities today!