Question

我无法理解为什么我无法在Flask函数和模板中从SQLAlchemy获取数据。这是代码： 1. main.py

    #!/usr/bin/env python
    # -*- coding: utf-8 -*-

    from flask import Flask, jsonify, request, g, render_template as render
    from models import *
    from settings import *
    from flask_httpauth import HTTPBasicAuth


    ALLOWED_EXTENSIONS = set(EXTENSIONS)
    auth = HTTPBasicAuth()

    app = Flask(__name__)
    app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER


    @app.route('/')
    def home_page():
        brands = [item.serialize for item in session.query(Category).all()]
        items = []
        title = ''
        print brands
        return render('catalog/index.html', brands=brands, cars=items, titlr=title)


    if __name__ == '__main__':
        app.debug = True
        app.run(host='0.0.0.0')

models.py：

#!/usr/bin/env python
# -*- coding: utf-8 -*-

from sqlalchemy import Column, Integer, String, ForeignKey, DateTime
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import relationship, sessionmaker
from sqlalchemy import create_engine
from passlib.apps import custom_app_context as pwd_context
from itsdangerous import TimedJSONWebSignatureSerializer as Serializer
from itsdangerous import BadSignature, SignatureExpired
from data_control import get_unique_str


Base = declarative_base()  # initialisation the database
secret_key = get_unique_str(32)  # create secret_key

# create session
engine = create_engine('sqlite:///catalog.db')
Base.metadata.bind = engine
DBSession = sessionmaker(bind=engine)
session = DBSession()


# TODO: User model
class User(Base):
    __tablename__ = 'user'
    id = Column(Integer, primary_key=True)
    username = Column(String(32), index=True)
    picture = Column(String(250), default='/img/no-img.png')
    first_name = Column(String(25), default=None)
    last_name = Column(String(25), default=None)
    email = Column(String(40))
    password_hash = Column(String(64))
    status = Column(String(10), default='user')

    def hash_password(self, password):
        """
        hash password

        :param password:
        :return void:
        """
        self.password_hash = pwd_context.encrypt(password)

    def verify_password(self, password):
        """
        Password verification

        :param password:
        :return bool:
        """
        return pwd_context.verify(password, self.password_hash)

    @property
    def get_full_name(self):
        """
        Return full name (first and last name)

        :return string:
        """
        return "%s %s" % (self.first_name, self.last_name)

    def generate_auth_token(self, expiration=3600):
        """
        Generate authentication token

        :param expiration:
        :return string: (token)
        """
        s = Serializer(secret_key, expires_in=expiration)
        return s.dumps({'uid': self.id})

    @staticmethod
    def verify_auth_token(token):
        """
        Try to load token, success return user id false return None

        :param token:
        :return mix:
        """
        s = Serializer(secret_key)
        try:
            data = s.loads(token)
        except SignatureExpired:
            # Valid Token, but expired
            return None
        except BadSignature:
            # Invalid Token
            return None
        uid = data['uid']
        return uid

    @property
    def serialize(self):
        """
        Return user data

        :return dict:
        """
        return {
            'id': self.id,
            'username': self.username,
            'picture': self.picture,
            'first_name': self.first_name,
            'last_name': self.last_name,
            'email': self.email,
            'status': self.status
        }


# TODO: Image model
class Image(Base):
    __tablename__ = 'image'
    id = Column(Integer, primary_key=True)
    product = Column(Integer, nullable=False)
    url = Column(String(250))

    @property
    def serialize(self):
        """
        Return user data

        :return dict:
        """
        return {
            'id': self.id,
            'url': self.url
        }


# TODO: Category model
class Category(Base):
    __tablename__ = 'category'
    id = Column(Integer, primary_key=True)
    name = Column(String(30))

    @property
    def serialize(self):
        """
        Return user data

        :return dict:
        """
        return {
            'id': self.id,
            'name': self.name
        }


# TODO: Catalog model
class Catalog(Base):
    __tablename__ = 'catalog'
    id = Column(Integer, primary_key=True)
    model = Column(String(30))
    title = Column(String(250))
    description = Column(String(250))
    category = Column(Integer, ForeignKey("category.id"), nullable=False)
    price = Column(Integer, nullable=False)
    author = Column(Integer, ForeignKey("user.id"), nullable=False)

    def get_author(self):
        """
        Return product`s author

        :return object:
        """
        return session.query(User).filter_by(id=self.author).one().serialize

    def get_images(self):
        """
        Prepare list of images for JSON

        :return list:
        """
        images = session.query(Image).filter_by(product=self.id).all()
        return [img.serialize for img in images]

    def get_category(self):
        """
        Return category

        :return object:
        """
        category = session.query(Category).filter_by(id=self.category).first()
        return category.serialize

    @property
    def serialize(self):
        """
        Return user data

        :return dict:
        """
        return {
            'id': self.id,
            'model': self.model,
            'title': self.title,
            'description': self.description,
            'brand': self.get_category(),
            'price': self.price,
            'images': self.get_images(),
            'author': self.get_author(),
        }


Base.metadata.create_all(engine)

模板中的

：

{% extends 'base.html' %}

{% block title %}{{ title }}{% endblock %}

{% block content %}

<div class="row">
{{ brands }}
{% for item in brands %}
  <div>{{ item.name }}</div>
{% endfor %}
{% for car in cars %}
 <div class="col-sm-4 col-lg-4">
  <div class="col-sm-6 col-lg-4 mb-5">
    <span class="tumbl-image" data-ng-click="main.showDescription()"
          image-bg="{{ car.images[0].url }}">
      <div class="hide description">{{ car.description }}</div>
    </span>
    <div class="pt-2 text-center" id="title-link">
      <a href="/car/{{ car.id }}">{{ car.title }}</a>
    </div>
    <div class="pt-2">
      <span data-ng-click="main.sendEmail(item.author.email)" class="mail-to">
        <i class="fa fa-envelope-o" aria-hidden="true"></i>
      </span>
      <a href="/profile/{{ car.author.id }}">{{ car.author.first_name }} {{ item.author.last_name }}</a>
    </div>
  </div>
 </div>
{% endfor %}
</div>
{% endblock %}

如果我运行app并转到localhost：5000，我会看到[]

在终端：

* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
* Restarting with stat
* Debugger is active!
* Debugger PIN: 342-567-684

[] 127.0.0.1 - - [11 / Dec / 2017 15:34:00]＆＃34; GET / HTTP / 1.1＆＃34; 200 -

但如果我运行python console：

    PyDev console: starting.
    import sys; print('Python %s on %s' % (sys.version, sys.platform))
    sys.path.extend(['/path/to/catalog'])
    Python 2.7.10 (default, Jul 15 2017, 17:16:57) 
    [GCC 4.2.1 Compatible Apple LLVM 9.0.0 (clang-900.0.31)] on darwin
    >>> from main import *
    >>> brands = [item.serialize for item in session.query(Category).all()]
    >>> print brands
    [{'id': 1, 'name': u'BMW'}, {'id': 2, 'name': u'Ford'}, {'id': 3, 'name': u'Nissan'}, {'id': 4, 'name': u'Toyota'}, {'id': 5, 'name': u'Dodge'}, {'id': 6, 'name': u'Audi'}, {'id': 7, 'name': u'Jeep'}, {'id': 8, 'name': u'Mazda'}, {'id': 9, 'name': u'Chevrolet'}]

有人请告诉我为什么烧瓶没有输出数据？提前谢谢。

Answer 1

我花了两天时间找到解决方案，但问题出在PyCharm上。我不知道为什么，但出于某种原因，如果我尝试在PyCharm中运行应用程序SQLAlchemy停止工作。如果我在终端中运行应用程序，它运行良好。

P.S。我希望这有助于某人。

Flask无法从sqlalchemy获取数据

1 个答案: