diff options
Diffstat (limited to 'test/wpt/tests/websockets/handlers/send-backpressure_wsh.py')
-rw-r--r-- | test/wpt/tests/websockets/handlers/send-backpressure_wsh.py | 39 |
1 files changed, 39 insertions, 0 deletions
diff --git a/test/wpt/tests/websockets/handlers/send-backpressure_wsh.py b/test/wpt/tests/websockets/handlers/send-backpressure_wsh.py new file mode 100644 index 0000000..d3288d0 --- /dev/null +++ b/test/wpt/tests/websockets/handlers/send-backpressure_wsh.py @@ -0,0 +1,39 @@ +#!/usr/bin/python + +import time + +# The amount of internal buffering a WebSocket connection has is not +# standardised, and varies depending upon the OS. Setting this number too small +# will result in false negatives, as the entire message gets buffered. Setting +# this number too large will result in false positives, when it takes more than +# 2 seconds to transmit the message anyway. This number was arrived at by +# trial-and-error. +MESSAGE_SIZE = 1024 * 1024 + +# With Windows 10 and Python 3, the OS will buffer an entire message in memory +# and return from send() immediately, even if it is very large. To work around +# this problem, send multiple messages. +MESSAGE_COUNT = 16 + + +def web_socket_do_extra_handshake(request): + # Turn off permessage-deflate, otherwise it shrinks our big message to a + # tiny message. + request.ws_extension_processors = [] + + +def web_socket_transfer_data(request): + # Send empty message to fill the ReadableStream queue + request.ws_stream.send_message(b'', binary=True) + + # TODO(ricea@chromium.org): Use time.perf_counter() when migration to python + # 3 is complete. time.time() can go backwards. + start_time = time.time() + + # The large messages that will be blocked by backpressure. + for i in range(MESSAGE_COUNT): + request.ws_stream.send_message(b' ' * MESSAGE_SIZE, binary=True) + + # Report the time taken to send the large message. + request.ws_stream.send_message(str(time.time() - start_time), + binary=False) |