mirror of https://github.com/encode/starlette.git
179 lines
5.7 KiB
Markdown
179 lines
5.7 KiB
Markdown
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Starlette includes a few response classes that handle sending back the
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appropriate ASGI messages on the `send` channel.
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### Response
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Signature: `Response(content, status_code=200, headers=None, media_type=None)`
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* `content` - A string or bytestring.
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* `status_code` - An integer HTTP status code.
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* `headers` - A dictionary of strings.
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* `media_type` - A string giving the media type. eg. "text/html"
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Starlette will automatically include a Content-Length header. It will also
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include a Content-Type header, based on the media_type and appending a charset
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for text types.
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Once you've instantiated a response, you can send it by calling it as an
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ASGI application instance.
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```python
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from starlette.responses import Response
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = Response('Hello, world!', media_type='text/plain')
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await response(scope, receive, send)
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```
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#### Set Cookie
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Starlette provides a `set_cookie` method to allow you to set cookies on the response object.
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Signature: `Response.set_cookie(key, value, max_age=None, expires=None, path="/", domain=None, secure=False, httponly=False)`
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* `key` - A string that will be the cookie's key.
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* `value` - A string that will be the cookie's value.
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* `max_age` - An integer that defines the lifetime of the cookie in seconds. A negative integer or a value of `0` will discard the cookie immediately. `Optional`
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* `expires` - An integer that defines the number of seconds until the cookie expires. `Optional`
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* `path` - A string that specifies the subset of routes to which the cookie will apply. `Optional`
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* `domain` - A string that specifies the domain for which the cookie is valid. `Optional`
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* `secure` - A bool indicating that the cookie will only be sent to the server if request is made using SSL and the HTTPS protocol. `Optional`
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* `httponly` - A bool indicating that the cookie cannot be accessed via Javascript through `Document.cookie` property, the `XMLHttpRequest` or `Request` APIs. `Optional`
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#### Delete Cookie
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Conversly, Starlette also provides a `delete_cookie` method to manually expire a set cookie.
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Signature: `Response.delete_cookie(key, path='/', domain=None)`
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### HTMLResponse
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Takes some text or bytes and returns an HTML response.
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```python
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from starlette.responses import HTMLResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = HTMLResponse('<html><body><h1>Hello, world!</h1></body></html>')
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await response(scope, receive, send)
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```
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### PlainTextResponse
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Takes some text or bytes and returns an plain text response.
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```python
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from starlette.responses import PlainTextResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = PlainTextResponse('Hello, world!')
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await response(scope, receive, send)
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```
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### JSONResponse
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Takes some data and returns an `application/json` encoded response.
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```python
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from starlette.responses import JSONResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = JSONResponse({'hello': 'world'})
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await response(scope, receive, send)
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```
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### UJSONResponse
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A JSON response class that uses the optimised `ujson` library for serialisation.
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Using `ujson` will result in faster JSON serialisation, but is also less careful
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than Python's built-in implementation in how it handles some edge-cases.
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In general you *probably* want to stick with `JSONResponse` by default unless
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you are micro-optimising a particular endpoint.
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```python
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from starlette.responses import UJSONResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = UJSONResponse({'hello': 'world'})
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await response(scope, receive, send)
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```
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### RedirectResponse
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Returns an HTTP redirect. Uses a 302 status code by default.
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```python
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from starlette.responses import PlainTextResponse, RedirectResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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if scope['path'] != '/':
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response = RedirectResponse(url='/')
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else:
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response = PlainTextResponse('Hello, world!')
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await response(scope, receive, send)
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```
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### StreamingResponse
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Takes an async generator or a normal generator/iterator and streams the response body.
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```python
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from starlette.responses import StreamingResponse
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import asyncio
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async def slow_numbers(minimum, maximum):
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yield('<html><body><ul>')
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for number in range(minimum, maximum + 1):
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yield '<li>%d</li>' % number
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await asyncio.sleep(0.5)
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yield('</ul></body></html>')
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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generator = slow_numbers(1, 10)
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response = StreamingResponse(generator, media_type='text/html')
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await response(scope, receive, send)
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```
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Have in mind that <a href="https://docs.python.org/3/glossary.html#term-file-like-object" target="_blank">file-like</a> objects (like those created by `open()`) are normal iterators. So, you can return them directly in a `StreamingResponse`.
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### FileResponse
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Asynchronously streams a file as the response.
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Takes a different set of arguments to instantiate than the other response types:
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* `path` - The filepath to the file to stream.
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* `headers` - Any custom headers to include, as a dictionary.
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* `media_type` - A string giving the media type. If unset, the filename or path will be used to infer a media type.
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* `filename` - If set, this will be included in the response `Content-Disposition`.
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File responses will include appropriate `Content-Length`, `Last-Modified` and `ETag` headers.
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```python
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from starlette.responses import FileResponse
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async def app(scope, receive, send):
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assert scope['type'] == 'http'
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response = FileResponse('statics/favicon.ico')
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await response(scope, receive, send)
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```
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