NameError: name 'app' is not defined - 在 Flask 上上传图像文件时

Question

尝试在烧瓶应用程序上上传图像时，我一直在尝试解决 Nameerror 'app not defined'。我很清楚这可能是一个结构性错误，但我似乎无法让它工作超过 48 小时。我在蓝图中重组了我的代码，受影响的蓝图是我的身份验证。
我尝试使用“应用程序导入应用程序”，但出现错误“无法从应用程序导入应用程序”

以下是我的代码

#app/auth/__init__.py

from flask import Blueprint


bp = Blueprint('auth', __name__)

from app.auth import views
                 

----------------------------------------------------
app/auth/views.py

from flask import render_template, redirect, url_for, flash, request
from flask_login import login_required, login_user, logout_user, current_user
from app import db
from app.auth import bp
from app.auth.forms import LoginForm, RegistrationForm, UpdateAccountForm
from app.models import User
import os
import urllib.request
from werkzeug.utils import secure_filename
import secrets
from PIL import Image



def save_picture(form_picture):
    random_hex = secrets.token_hex(8)
    _, f_ext = os.path.splitext(form_picture.filename)
    picture_fn = random_hex + f_ext
    picture_path = os.path.join(app.root_path, 'passports', picture_fn)
    
    output_size = (125, 125)
    i = Image.open(form_picture)
    i.thumbnail(output_size)
    i.save(picture_path)
    return picture_fn

 

@bp.route("/account", methods=['GET', 'POST'])
@login_required
def account():
    form = UpdateAccountForm()
    if form.validate_on_submit():
        if form.picture.data:
            picture_file = save_picture(form.picture.data)
            current_user.image_file = picture_file
        current_user.username = form.username.data
        current_user.email = form.email.data
        
        db.session.commit()

        flash('Your account has been updated!', 'success')
        return redirect(url_for('auth.account'))

    elif request.method == 'GET':
        form.username.data = current_user.username
        form.email.data = current_user.email
    image_file = url_for('static', filename='passports/' + current_user.image_file)
    return render_template('auth/account.html', title='Account',
                           image_file=image_file, form=form)

app/__init__.py


import logging
from logging.handlers import SMTPHandler, RotatingFileHandler
import os
from flask import Flask, request, current_app
from config import Config
from flask_bootstrap import Bootstrap
from flask_login import LoginManager
from flask_migrate import Migrate
from flask_sqlalchemy import SQLAlchemy
from flask_assets import Bundle, Environment


db = SQLAlchemy()
migrate = Migrate()
login = LoginManager()
login.login_view = 'auth.login'
#mail = Mail()
bootstrap = Bootstrap()



# Initialize the app
def create_app(config_class=Config):
    app=Flask(__name__)
    app.config.from_object(config_class)

    

    db.init_app(app)
    migrate.init_app(app, db)
    login.init_app(app)
    bootstrap.init_app(app)
    

    from app.admin import bp as admin_bp
    app.register_blueprint(admin_bp, url_prefix='/admin')

    from app.auth import bp as auth_bp
    app.register_blueprint(auth_bp)

    from app.home import bp as home_bp
    app.register_blueprint(home_bp)

    from app.errors import bp as errors_bp
    app.register_blueprint(errors_bp)



   
    return app



from app import views, models

Answer 1

对不起，我会向你解释。
如果您导入 current_app 并将其用作对当前正在运行的应用程序的引用，则不必导入 app。您可以像以前一样使用工厂并引用应用程序对象。

from flask import current_app

def save_picture(form_picture):
    random_hex = secrets.token_hex(8)
    _, f_ext = os.path.splitext(form_picture.filename)
    picture_fn = random_hex + f_ext
    picture_path = os.path.join(current_app.root_path, 'passports', picture_fn)
    
    output_size = (125, 125)
    i = Image.open(form_picture)
    i.thumbnail(output_size)
    i.save(picture_path)
    return picture_fn