Tremolo provides a Server-Sent Events (SSE) helper to send continuous data over HTTP.
Just like the WebSocket way, you only need to put the sse=None placeholder in the handlers to be able to send SSE data.
@app.route('/sse')
async def sse_handler(sse=None, **server):
if sse is None:
# for some reason, the sse object was not created
# due to an invalid request
raise BadRequest
await sse.send('Hel\nlo', event='greeting')
await sse.send('World!', event='greeting')
await sse.close()
The client should see the following response body:
data: Hel
data: lo
event: greeting
data: World!
event: greeting
You may need to add some CORS headers.
Here’s a simple example, but not necessarily a good way to do it.
@app.route('/sse')
async def sse_handler(sse=None, **server):
if sse is None:
# for some reason, the sse object was not created
# due to an invalid request
raise BadRequest
# set CORS headers with the response object
sse.response.set_header(b'Access-Control-Allow-Credentials', b'true')
if b'origin' in sse.request.headers:
sse.response.set_header(
b'Access-Control-Allow-Origin', sse.request.headers[b'origin']
)
await sse.send('Hel\nlo', event='greeting')
await sse.send('World!', event='greeting')
await sse.close()