The little ASGI library that shines.
Project description
Starlette
The little ASGI library that shines
from starlette import Response
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
response = Response('Hello, world!', media_type='text/plain')
await response(receive, send)
Responses
Starlette includes a few response classes that handle sending back the
appropriate ASGI messages on the send channel.
Response
Signature: Response(content, status_code, headers, media_type)
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
response = Response('Hello, world!', media_type='text/plain')
await response(receive, send)
HTMLResponse
Takes some text or bytes and returns an HTML response.
from starlette import HTMLResponse
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
response = HTMLResponse('<html><body><h1>Hello, world!</h1></body></html')
await response(receive, send)
JSONResponse
Takes some data and returns an application/json encoded response.
from starlette import JSONResponse
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
response = JSONResponse({'hello': 'world'})
await response(receive, send)
StreamingResponse
Takes an async generator and streams the response body.
from starlette import Request, StreamingResponse
import asyncio
async def slow_numbers(minimum, maximum):
yield('<html><body><ul>')
for number in range(minimum, maximum + 1):
yield '<li>%d</li>' % number
await asyncio.sleep(0.5)
yield('</ul></body></html>')
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
generator = slow_numbers(1, 10)
response = StreamingResponse(generator, media_type='text/html')
await response(receive, send)
Requests
Starlette includes a Request class that gives you a nicer interface onto
the incoming request, rather than accessing the ASGI scope and receive channel directly.
Request
Signature: Request(scope, receive)
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
request = Request(self.scope, receive)
content = '%s %s' % (request.method, request.url.path)
response = Response(content, media_type='text/plain')
await response(receive, send)
Method
The request method is accessed as request.method.
URL
The request URL is accessed as request.url.
The property is actually a subclass of str, and also exposes all the
components that can be parsed out of the URL.
For example: request.url.path, request.url.port, request.url.scheme.
Headers
Headers are exposed as an immutable, case-insensitive, multi-dict.
For example: request.headers['content-type']
Query Parameters
Headers are exposed as an immutable multi-dict.
For example: request.query_params['abc']
Body
There are two interfaces for returning the body of the request:
The request body as bytes: await request.body()
The request body, parsed as JSON: await request.json()
Test Client
The test client allows you to make requests against your ASGI application,
using the requests library.
from starlette import HTMLResponse, TestClient
class App:
def __init__(self, scope):
self.scope = scope
async def __call__(self, receive, send):
response = HTMLResponse('<html><body>Hello, world!</body></html>')
await response(receive, send)
def test_app():
client = TestClient(App)
response = client.get('/')
assert response.status_code == 200
Decorators
The asgi_application decorator turns an async function into an ASGI application.
The function must take a single request argument, and return a response.
from starlette import asgi_application, HTMLResponse
@asgi_application
async def app(request):
return HTMLResponse('<html><body>Hello, world!</body></html>')
API Star is BSD licensed code.
Designed & built in Brighton, England.
— ⭐️ —
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