A Simple Test HTTP server from Flask

Last night I found myself needing to update some app code to switch from a synchronous http call to an async one. This is not a particularly hard problem but it can be tricky to get correct.

What I needed therefore was a way to test these http calls, and the machine I was using didn't already have any http servers running to use as the target.

No problem: it has Python - and that's all you need.

Don't Install - Just create

This pattern has been forming for me. For simple tasks, it's often easier to just write a little utility script instead of installing some full blown software to do a job.

If you need a real server, by all means go for it (but even then I'd suggest Docker if possible). But if you just need a quick endpoint to test with or to solve a single use case then Python is probably your friend.

I'm saying Python specifically because it's rather ubiquitous with a rich standard library and ecosystem.

Server code

The idea with this simple server was to help me test the async client calls so I wanted it to wait 5 seconds and then respond. I just wanted it to respond to any standard call with a 200 after 5 seconds.

from flask import Flask, request
import time

app = Flask(__name__)

@app.route('/', defaults={'path': ''}, methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH'])
@app.route('/<path:path>', methods=['GET', 'POST', 'PUT', 'DELETE', 'PATCH'])
def catch_all(path):
    print(f"Path: {path}")
    print(f"Headers: {dict(request.headers)}")
    print(f"Params: {request.args}")
    print(f"Data: {request.data}")

    # Wait for 5 seconds
    time.sleep(5)

    return "yessir"

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)