Flask

Flask 的 redirect 的目标地址会自动加上 schema://host，也就是 absoluteURI。 在反向代理服务后面时，会有一些问题，需要 X-Forwarded-* 系列的 header 来配合， 且需要相关 fix，见: https://werkzeug.palletsprojects.com/en/latest/middleware/proxy_fix/ https://flask.palletsprojects.com/en/2.0.x/quickstart/#hooking-in-wsgi-middleware 。

其实不支持 relativeURI 才是合规的表现，见 https://datatracker.ietf.org/doc/html/rfc2616#section-14.30 。

wsgi.py

#!/usr/bin/env python3

from flask import Flask, redirect, request
app = Flask(__name__)

# https://werkzeug.palletsprojects.com/en/latest/middleware/proxy_fix/
# https://flask.palletsprojects.com/en/2.0.x/quickstart/#hooking-in-wsgi-middleware
from werkzeug.middleware.proxy_fix import ProxyFix
app.wsgi_app = ProxyFix(app.wsgi_app)

@app.route("/")
def root():
    return redirect("/hello")

@app.route("/hello")
def hello():
    return "hello world: " + request.url


if __name__ == "__main__":
    # ./wsgi.py
    if __debug__:
        app.run(host="0.0.0.0", port=8000, debug=True)  # equivalent to: $ FLASK_DEBUG=1 flask run -h '' -p 8000
    # PYTHONOPTIMIZE=1 ./wsgi.py
    import bjoern
    bjoern.run(app.wsgi_app, "0.0.0.0", 80)