ziplineio 0.1.16

The funnest ASGI Web Framework

ZipLine

ZipLine is a simple asyncronous ASGI web framework for Python. It is designed to be simple and easy to use, while still being powerful and flexible.

• Quick Start
• Handlers
• Middleware
• Dependency Injection
• Routing
• Validation
• Static Files
• HTML Templates

Quick Start

from zipline import ZipLine

app = ZipLine()

@app.route("/")
async def home(request):
    planet = request.query.get("planet")
    return f"Hello, {planet}!"

uvicorn my_awesome_project:app

curl http://localhost:8000/?planet=Earth

Handlers

a ZipLine handler is a simple async function that takes a request object and returns a response, or throws an exception.

A response can be bytes, str, dict, or the ZipeLine Response object.

If a dict is returned, it will be serialized to JSON.

If an Exception is thrown, it will be caught and handled by the framework, returning a basic error response.

Middleware

Zipline middleware is inspired by Express.js. Any number of handler functions can be added to the middleware stack.

Each middleware function is just another ZipLine Handler.

Middleware functions are called in the order they are added to the stack, and pass along their context to the next handler.

The first handler in the stack to return something other than a Request object (including Exception) will short-circuit the stack and return the response.

Middleware can be can be applied at the application, router, or individual route level.

from zipline import ZipLine, Router, middleware


# middleware functions
def auth_middleware(request):
    if request.headers.get("Authorization") == "Bearer 1234":
        is_authed = True
    else:
        is_authed = False
    return request, { "is_authed": is_authed }

def auth_guard(request, ctx):
    if not ctx.get("is_authed"):
        raise Exception("Unauthorized")

def is_user_guard(request, ctx):
    if ctx.get("user_id") != request.path_params.get("id"):
        raise Exception("Forbidden")


app = ZipLine()


# apply middleware to all routes
app.middleware([auth_middleware])

user_router = Router("/user")

# apply middleware at the router-level
user_router.middleware([auth_guard])

@app.get("/profile")
@middleware([is_user_guard]) # apply middleware to one router
async def user_profile(request):
    return "Hello, World!"

Dependency Injection

Like with middeleware, ZipLine supports dependency injection at the route, router, or application level. In addition, dependencies can be injected into other dependencies. Dependencies are passed to the handler function as keyword arguments.

from zipline import ZipLine, inject

class LoggingService:
    def log_request(self, request):
        print(f"Request to {request.url}")

class UserService:
    def __init__(self):
        self.connection = "Connected to database"

    def get_user():
        return "User"

app = ZipLine()

# available to all routes
app.inject(LoggingService)

@app.route("/")
@inject(UserService, name="user_service")
async def home(request, user_service: UserService, logger: LoggingService):
    logger.log_request(request)
    return user_service.get_user()

Services can be any class, but Zipline includes a special Service class. Classes that inherit from Service have the ability to access all other services in their scope.

Classes that inherit from Service are expected to have a property name which is used to identify the service in the dependency injection container. Otherwise, they can be referenced by their class name (like with the @inject decorator).

from zipline import ZipLine, Service

class LoggingService(Service):
    name = "logger"

    def error(self, message):
        print(f"Error! {message}")

class DBService(Service):
    name = "db_service"

    def __init__(self, logger: LoggingService):
        self.logger = logger

    def get_connection(self):
        try:
            return db.connect()
        except Exception as e:
            self.logger.error(e)

class UserService(Service):
    name = "user_service"

    def __init__(self, db_service: DBService, logger: LoggingService):
        self.db_service = db_service
        self.logger = logger

    def get_user(id: str):
        conn = self.db_service.get_connection()
         try:
            return conn.query("SELECT * FROM users WHERE id = ?", id)
        except Exception as e:
            self.logger.error(f"User {id} not found")


app = ZipLine()
# inject all services; order doesn't matter
app.inject([LoggingService, DBService, UserService])

@app.route("/user/:id")
async def get_user(request):
    user_id = request.path_params.get("id")
    return user_service.get_user(user_id)

Routing

Like Express.js, ZipLine supports multiple, nested routers.

from zipline import ZipLine, Router

app = ZipLine()

user_router = Router("/user")

@user_router.get("/:id")
async def get_user(request):
    return f"User {request.path_params.get('id')}"

app.router(user_router)

Validation

Zipline provides powerful decorators for validating query parameters and request bodies, ensuring your endpoints receive correctly formatted data. These decorators help you enforce data types, handle missing parameters, and validate against complex data structures.

Query Parameter Validation

To validate query parameters, use the @validate_query decorator. You can specify each parameter you want to validate by creating a QueryParam instance, which includes the parameter name, expected type, and whether it is required.

Example: Simple Query Parameter Validation

from ziplineio.validation.query import QueryParam, validate_query
from ziplineio.request import Request

@app.get("/")
@validate_query(QueryParam("username", str), QueryParam("age", float))
async def get_user_handler(req: Request):
    username = req.query_params.get("username")
    age = req.query_params.get("age")
    return {"username": username, "age": age}

In this example, the endpoint expects username to be a string and age to be a float. If the parameters are missing or of the wrong type, a validation error is returned.

#### Example: Simple Body Parameter Validation

```python
from ziplineio.validation.body import BodyParam, validate_body
from ziplineio.request import Request

@app.post("/")
@validate_body(BodyParam("username", str), BodyParam("age", float))
async def create_user_handler(req: Request):
    username = req.body.get("username")
    age = req.body.get("age")
    return {"username": username, "age": age}

Example: Using Pydantic Models for Body Validation

from pydantic import BaseModel
from ziplineio.validation.body import BodyParam, validate_body

class UserModel(BaseModel):
    username: str
    age: int

@app.post("/")
@validate_body(BodyParam("user", UserModel))
async def create_user_handler(req: Request):
    user = req.body.get("user")
    return {"user": user.model_dump()}

Optional Parameters

By default, all parameters are required. To make a parameter optional, set the required parameter to False.

from ziplineio.validation.query import QueryParam, validate_query

@app.get("/")
@validate_query(QueryParam("username", str), QueryParam("age", float, required=False))
async def get_user_handler(req: Request):
    username = req.query_params.get("username")
    age = req.query_params.get("age")
    return {"username": username, "age": age}

Static Files

ZipLine can serve static files from a directory.

from zipline import ZipLine


app = ZipLine()

# path_prefix is optional; defaults to "/static"
app.static("test/mocks/static", path_prefix="/my_static_url")

HTML Templates

ZipLine can render HTML templates using Jinja2.

The jinja decorator takes a Jinja2 Environment object and a template name to be rendered by the handler. Rather than a regular response, the handler should return a dictionary of context variables to be passed to the template.

from jinja2 import Environment, PackageLoader, select_autoescape
from ziplineio. import ZipLine
from ziplineio.html.jinja import jinja

env = Environment(loader=PackageLoader("myapp"), autoescape=select_autoescape())

app = ZipLine()
app.static("static_files")

@app.get("/")
@jinja(env, "home.html")
def home(req):
    return {"message": "Hello, world!"}