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vrslev/main.py

Last active November 3, 2024 15:35
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Automatic browser reloading in FastAPI
Raw
main.py
import os
import arel
from fastapi import FastAPI, Request
from fastapi.templating import Jinja2Templates
app = FastAPI()
templates = Jinja2Templates("templates")
if _debug := os.getenv("DEBUG"):
hot_reload = arel.HotReload(paths=[arel.Path(".")])
app.add_websocket_route("/hot-reload", route=hot_reload, name="hot-reload")
app.add_event_handler("startup", hot_reload.startup)
app.add_event_handler("shutdown", hot_reload.shutdown)
templates.env.globals["DEBUG"] = _debug
templates.env.globals["hot_reload"] = hot_reload
@app.get("/")
def index(request: Request):
return templates.TemplateResponse("index.html", context={"request": request})
# run:
# DEBUG=true uvicorn main:app --reload
Raw
requirements.txt
fastapi
uvicorn[standard]
arel
jinja2
Raw
templates-base.html
<body>
{% block content %}{% endblock %}
<!-- Hot reload script -->
{% if DEBUG %} {{ hot_reload.script(url_for('hot-reload')) | safe }} {% endif
%}
</body>
Raw
templates-index.html
{% extends "base.html" %} {% block content %} Hello, world! {% endblock %}
@dicolasi
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dicolasi commented Sep 1, 2023

I can see a WS connection open from the logs:

Done in 79ms.
INFO:     Application startup complete.
INFO:     127.0.0.1:53242 - "GET / HTTP/1.1" 200 OK
INFO:     ('127.0.0.1', 53244) - "WebSocket /hot-reload" [accepted]
INFO:     connection open

and I can see the script in html:

<html lang="en">
<head>
    <link rel="stylesheet" href="http://127.0.0.1:8000/static/css/main.css" type="text/css" />
    <meta name="description" content="Home page description FUCKER!" />
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width" />
    <title>Home</title>
</head>
<body>
     
    <section id="body" class="flex flex-col bg-slate-50 justify-center items-center max-w-screen-lg m-auto">
        <div class="flex flex-col justify-center items-center py-10">
            <h2 class="text-2xl leading-relaxed text-slate-800 uppercase">Welcomsdsdsdsddsdsdsdsdsdsdsdsa</h2>
            <div class="flex flex-col justify-center content-center text-center">
                <img src="https://i.discogs.com/mXy5VCH7vfETEiVVrn4Slw_wKARXL7zYBcvEzQWwb7k/rs:fit/g:sm/q:90/h:544/w:600/czM6Ly9kaXNjb2dz/LWRhdGFiYXNlLWlt/YWdlcy9BLTUyMzEy/My0xNTcwMTc4NjE4/LTE2MTQuanBlZw.jpeg"/>
                <span class="py-4 uppercase font-bold">Beirut</span>
            </div>
        </div>
    </section>

      <script>const ws = new WebSocket("ws://127.0.0.1:8000/hot-reload");
ws.onmessage = () => window.location.reload();
</script> 
</body>
</html>

however the page does not get reloaded on save. Am I missing something?

@thisisthemurph
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This works for me, but only on the routes defined within the main file where app is defined. Any ideas on how to get this to work on other routes? I have separate routes defined within a routers directory and then apply them in the main file with app.include_router(my_router).

@vrslev
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vrslev commented Oct 24, 2023

@dicolasi Please share your code 😊

@vrslev
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vrslev commented Oct 24, 2023

@thisisthemurph I don't understand exactly your setup. Can you share a minimal reproducible example of what you're saying?

@yanky2000
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It works in Safari (Version 17.2 (19617.1.17.11.9)) just fine.

@vrslev
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vrslev commented Dec 20, 2023

It works in Safari (Version 17.2 (19617.1.17.11.9)) just fine.

@yanky2000 Just tested it in Safari 17.1—it also works. Removed the comment, thanks.

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