multiprocessing or threading (depending on what level of parallelism you need) to spawn one or more consumers when the WSGI app starts, and signal/join the consumer when the app stops.
resp.set_header('content-disposition', 'inline; filename="some-filename.pdf"')downloadable_as sets the disposition to attachment instead of inline, causing the browser to either save immediately or open a Save As dialog.
Agreed, although downloadable_as should probably stay as-is, since its name does imply download.
Maybe we could add a new resp method to set the Content-Disposition header? Documentation is a good starting point, but I've made downloadable_as slightly more complex to follow best practices for non-ASCII filename encoding (and IIRC @CaselIT has fixed a bug there since).
I need some small help, somehow I cannot find an easy solution to forwarding a stream from one request to other.
I request one service using aiohttp like
async with aiohttp.ClientSession() as session:
async with session.get(request, params=param_dict) as response:
body = await response.read()
if response.status == 200:
return body
And then I would like to just attach the same body as a stream to response from falcon app. But when I use resp.data = body it does not work. If I manually create an IOBytestream then it complains that you cannot use byte object in await.
Any help ?
Hi @kamraj:matrix.org !
Note that return body is no different from just return, as Falcon does not use the return value when calling a responder. Falcon responders are expected to operate on req and resp instead.
Using resp.data = await response.read() should work, although it would buffer the whole response in a bytestring first.
I'm no expert of aiohttp, but you should also be able to simply set resp.stream to response, i.e.:
async with session.get(request, params=param_dict) as response:
resp.stream = responseSee also: When would I use media, data, and stream?
If possible and known from response, you might also want to set resp.content_length and resp.content_type, but that is of course optional.
requests: https://github.com/falconry/falcon/issues/1271#issuecomment-401612434.
Hm, setting resp.stream to response seems problematic wrt aiohttp's lifetime management. Furthermore, constructing a new session every time is considered an antipattern.
All that said, using response.read() works for me:
import aiohttp
import falcon.asgi
class Proxy(object):
UPSTREAM = 'https://falconframework.org'
async def handle(self, req, resp):
headers = dict(req.headers, Via='Falcon')
for name in ('host', 'connection', 'referer'):
headers.pop(name, None)
async with aiohttp.ClientSession() as session:
async with session.get(
self.UPSTREAM + req.path, headers=headers) as response:
resp.data = await response.read()
resp.content_type = response.headers.get(
'Content-Type', falcon.MEDIA_HTML)
resp.status = response.status
app = falcon.asgi.App()
app.add_sink(Proxy().handle)Save the above as test.py, and run with uvicorn test:app, then navigate to http://127.0.0.1:8000.
httpx, to perform similar proxying: A More Complex Example. (But there is no advanced session management there either.)
From what I understand since requests are not async, they would block the server.
requests (the library), then yes, requests are sync-only. I'm not opinionated on httpx vs aiohttp, although httpx seems to be getting more and more traction. Furthermore, I've heard the upcoming version of urllib3 will also support async (or maybe it already does?).
@kamraj:matrix.org This is how you can stream responses with httpx:
import falcon.asgi
import httpx
class Proxy(object):
UPSTREAM = 'https://falconframework.org'
def __init__(self):
self._client = httpx.AsyncClient()
async def handle(self, req, resp):
headers = dict(req.headers, Via='Falcon')
for name in ('host', 'connection', 'referer'):
headers.pop(name, None)
request = httpx.Request(
req.method, self.UPSTREAM + req.path, headers=headers)
response = await self._client.send(request, stream=True)
resp.stream = response.aiter_bytes()
resp.content_type = response.headers.get(
'Content-Type', falcon.MEDIA_HTML)
resp.status = response.status_code
# See also:
# https://www.python-httpx.org/async/#streaming-responses
resp.schedule(response.aclose)
app = falcon.asgi.App()
app.add_sink(Proxy().handle)Note that there is a caveat re manually streaming responses without a context manager & closing the response object, see also: https://www.python-httpx.org/async/#streaming-responses. I've adapted the provided example (using another framework) to Falcon.