Flask - 404 未找到：在服务器上未找到请求的 URL。 如果您手动输入 URL，请检查您的拼写并重试

Question

I'm completely new to Flask. As a beginner I'm trying to print 'Hello World' on a web page. When run this Flask application, the browser throwing me a 404 error. It says The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again. The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.

Here is my __init__.py :

from flask import Flask

app = Flask(__name__)

from app import app

My routes.py file:

from app import app

@app.route('/')
@app.route('/index')
def index():
    return "Hello, World!"

And my microApp.py file:

from app import app

Here is my working directory:

My Project/
  venv/
  app/
    __init__.py
    routes.py
  microApp.py

I set FLASK_APP = microApp.py and tried to run Flask. But the browser is throwing me an error.

Please anyone help me, I'm a noob. Thanks in advance.

Answer 1

When you are importing app that means your basically importing __init__.py file. The __init__.py files are modules that initialize the packages. modules So in your __init__.py file you importing again 'app'. Here you have to call 'routes'.

Answer 2

A server that does print "Hello world":

from flask import Flask 

app = Flask(__name__)

@app.route("/")
@app.route('/index')
def hello_world():
    return "Hello world!"

app.run('127.0.0.1', port=5500)

Answer 3

I got here trying to solve an error on a more complex page, involving chartjs.

What solved to me was sending back to an older library:

Instead of: https://cdnjs.cloudflare.com/ajax/libs/Chart.js/2.9.4/Chart.min.js' Solved with: https://cdnjs.cloudflare.com/ajax/libs/Chart.js/1.0.2/Chart.min.js'

Newer library did not support the type of graph that I wanted.