Question

我目前正在使用CS50的Python和JavaScript类进行Web编程。我正在尝试运行Flask服务器，但是却遇到了flask.cli.NoAppException错误。我正在尝试连接到heroku上的postGRES SQL数据库。

运行Mac OX Mojave版本10.14.4并使用bash命令行
能够连接到项目的管理员工具
能够连接到heroku并查看凭证以获取烧瓶的URI 环境
确认所有必需的软件包都已通过pip3 install -r v安装 requirements.txt
尝试使用自制软件更新SSL
尝试卸载psycopg2库并安装psycopg2-binary库用点子


import os

from flask import Flask, session
from flask_session import Session
from sqlalchemy import create_engine
from sqlalchemy.orm import scoped_session, sessionmaker

app = Flask(__name__)

# Check for environment variable
if not os.getenv("DATABASE_URL"):
    raise RuntimeError("DATABASE_URL is not set!!!")

# Configure session to use filesystem
app.config["SESSION_PERMANENT"] = False
app.config["SESSION_TYPE"] = "filesystem"
Session(app)

# Set up database
engine = create_engine(os.getenv("DATABASE_URL"))
db = scoped_session(sessionmaker(bind=engine))


@app.route("/")
def index():
    return "Project 1: TODO"

Bash命令提示符：

Stephens-MacBook-Pro:Project1 stephen$ export FLASK_APP=application.py
Stephens-MacBook-Pro:Project1 stephen$ export FLASK_DEBUG=1
Stephens-MacBook-Pro:Project1 stephen$ export DATABASE_URL="postgres://qipeqvvmvvcoqf:1c6aaa3504a58aa2b9be46b85d79a05159f5ccb1f64e3e27070a024a02c3b83e@ec2-174-129-208-118.compute-1.amazonaws.com:5432/d3lrnl0okcg99k"
Stephens-MacBook-Pro:Project1 stephen$ flask run
 * Serving Flask app "application.py" (lazy loading)
 * Environment: production
   WARNING: Do not use the development server in a production environment.
   Use a production WSGI server instead.
 * Debug mode: on
 * Running on http://127.0.0.1:5000/ (Press CTRL+C to quit)
 * Restarting with stat
 * Debugger is active!
 * Debugger PIN: 334-645-143

当我打开http://127.0.0.1:5000/时，应该看到文本“ Project 1：TODO”！

Error Screenshot

Answer 1

通常在一个或多个程序包损坏时发生。尝试使用pip更新所有软件包使用以下命令

pip install -I, --ignore-installed -r requirements.txt

运行Flask服务器时如何修复flask.cli.NoAppException

1 个答案: