Last active
May 30, 2024 15:03
-
-
Save ahopkins/9cdf98147da863a0c1c5b0b8581d6980 to your computer and use it in GitHub Desktop.
Server Sent Events
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| <!DOCTYPE html> | |
| <script> | |
| let eventSource | |
| let in_focus = true | |
| let should_run = false | |
| window.onblur = function () { | |
| in_focus = false | |
| } | |
| window.onfocus = function () { | |
| in_focus = true | |
| if (should_run) { | |
| start() | |
| } | |
| } | |
| function start() { | |
| should_run = true | |
| if (!window.EventSource) { | |
| // IE or an old browser | |
| alert("The browser doesn't support EventSource.") | |
| return | |
| } | |
| eventSource = new EventSource('/sse') | |
| eventSource.onopen = function (e) { | |
| log("Event: open") | |
| } | |
| eventSource.onerror = function (e) { | |
| log("Event: error") | |
| if (this.readyState == EventSource.CONNECTING) { | |
| log(`Reconnecting (readyState=${this.readyState})...`) | |
| } else { | |
| log("Error has occured.") | |
| } | |
| } | |
| eventSource.addEventListener('bye', function (e) { | |
| log("Event: bye, data: " + e.data) | |
| if (e.data == "close") { | |
| eventSource.close() | |
| } | |
| }) | |
| eventSource.addEventListener('first_only', function (e) { | |
| log("Event: first_only, data: " + e.data) | |
| }) | |
| eventSource.onmessage = function (e) { | |
| log("Event: message, data: " + e.data) | |
| if (!in_focus) { | |
| do_stop() | |
| } | |
| } | |
| } | |
| function stop(manual) { | |
| should_run = false | |
| do_stop() | |
| } | |
| function do_stop() { | |
| eventSource.close() | |
| log("eventSource.close()") | |
| } | |
| function log(msg) { | |
| console.log(msg) | |
| logElem.innerHTML += msg + "<br>" | |
| document.documentElement.scrollTop = 99999999 | |
| } | |
| function reset() { | |
| document.querySelector("#logElem").innerHTML = "" | |
| } | |
| </script> | |
| <button onclick="start()">Start</button> | |
| <button onclick="stop()">Stop</button> | |
| <button onclick="reset()">Clear</button> | |
| <pre id="logElem" style="margin: 6px 0"></pre> |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| import asyncio | |
| from itertools import count | |
| from sanic import Sanic | |
| from sanic.request import Request | |
| from sanic.response import redirect | |
| c = count() | |
| app = Sanic("__BASE__") | |
| asyncio.set_event_loop_policy(None) | |
| @app.get("/sse") | |
| async def sse(request: Request): | |
| print("Incoming SSE") | |
| headers = {"Cache-Control": "no-cache"} | |
| response = await request.respond( | |
| headers=headers, content_type="text/event-stream" | |
| ) | |
| await response.send("event: first_only\n") | |
| while True: | |
| i = next(c) | |
| await response.send(f"data: {i}\n\n") | |
| await asyncio.sleep(1) | |
| if i and i % 4 == 0: | |
| await response.send("event: bye\n") | |
| await response.send("data: close\n\n") | |
| break | |
| await response.send("event: message\n") | |
| print("Done") | |
| app.static("/index.html", "./index.html") | |
| @app.route("/") | |
| def index(request): | |
| return redirect("/index.html") | |
| app.run(port=9999, dev=True) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment