starlette/responses.md at 25990db22ea036a7af7840b19b0b272679603691

4.0 KiB

Raw Blame History

Starlette includes a few response classes that handle sending back the appropriate ASGI messages on the send channel.

Response

Signature: Response(content, status_code=200, headers=None, media_type=None)

content - A string or bytestring.
status_code - An integer HTTP status code.
headers - A dictionary of strings.
media_type - A string giving the media type. eg. "text/html"

Starlette will automatically include a Content-Length header. It will also include a Content-Type header, based on the media_type and appending a charset for text types.

Once you've instantiated a response, you can send it by calling it as an ASGI application instance.

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)

PlainTextResponse

Takes some text or bytes and returns an plain text response.

from starlette import PlainTextResponse


class App:
    def __init__(self, scope):
        self.scope = scope

    async def __call__(self, receive, send):
        response = PlainTextResponse('Hello, world!')
        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)

RedirectResponse

Returns an HTTP redirect. Uses a 302 status code by default.

from starlette import PlainTextResponse, RedirectResponse


class App:
    def __init__(self, scope):
        self.scope = scope

    async def __call__(self, receive, send):
        if self.scope['path'] != '/':
            response = RedirectResponse(url='/')
        else:
            response = PlainTextResponse('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)

FileResponse

Asynchronously streams a file as the response.

Takes a different set of arguments to instantiate than the other response types:

path - The filepath to the file to stream.
headers - Any custom headers to include, as a dictionary.
media_type - A string giving the media type. If unset, the filename or path will be used to infer a media type.
filename - If set, this will be included in the response Content-Disposition.

File responses will include appropriate Content-Length, Last-Modified and ETag headers.

from starlette import FileResponse


class App:
    def __init__(self, scope):
        self.scope = scope

    async def __call__(self, receive, send):
        response = FileResponse('/statics/favicon.ico')
        await response(receive, send)

— ⭐️ —

Starlette is BSD licensed code. Designed & built in Brighton, England.

4.0 KiB Raw Blame History Unescape Escape