FLask插件

時間  2019-12-10
標籤 flask 插件 欄目 Python 简体版
原文   原文鏈接

Flask插件

flask-session

  • 下載html

    pip install Flask-session

  • 導入python

    from flask_session import Session

  • 實例化sessionmysql

    在__init__文件中redis

    def create_app():
  app = Flask(__name__)
  Session(app)
  return app

  • 配置文件sql

    SESSION_TYPE = 'redis'

  • 用法和內置session同樣數據庫

  • 實現原理django

    • 內置的session調用 session_interface = xxxx
      • xxxx.open_session 解密cookie轉化成字典給session
      • xxxx.save_session 將session加密給cookie
    • Flask-session 修改session_interface 制定的類
      • 來改變session存儲的位置

SQLALchemy

建立鏈接

from sqlalchemy import create_engine
conn = create_engine(
    # 'mysql+pymysql://rout用戶:密碼@鏈接地址:端口號/數據庫名?charset=編碼方式'
    'mysql+pymysql://root:123@127.0.0.1:3306/day103?charset=ustf8',
    max_overflow = 0,   # 超過鏈接池大小外最多建立的鏈接數
    pool_size = 5,  # 鏈接池大小
    pool_timeout=30,    # 鏈接池中沒有線程最多等待時間,不然報錯
    pool_recycle=-1,    # 多久以後對鏈接池中的鏈接進行回收(重置), -1不回收
    
)

如何建立表

  • 導入flask

    from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()

  • 單表建立安全

    class Book(Base):
   __tablename__ = "book"

   id = Column(Integer, primary_key=True)
   title = Column(String(32), nullable=False，index=True)

   def __repr__(self):
      return self.title

   __table_args__ = (
      # 聯合惟一
      UniqueConstraint("id", "title", name="uni_id_title"),
      # 聯合索引
      Index("id", "title")
   )
    from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, DateTime
from sqlalchemy import Index, UniqueConstraint
import datetime
# 鏈接數據庫
ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",)
# 實例化
Base = declarative_base()

# 建立單表,繼承Base
class UserInfo(Base):
    __tablename__ = "user_info"

    id = Column(Integer, primary_key=True)
    name = Column(String(32), index=True, nullable=False)
    email = Column(String(32), unique=True)
    create_time = Column(DateTime, default=datetime.datetime.now)
# 相似與django中的class Meta, 針對於本表
    __table_args__ = (
        # 設置聯合惟一
        UniqueConstraint("id", "name", name="uni_id_name"),
        # 設置聯合索引
        Index("name", "email")
    )

# 函數,方便建立表
def create_db():
    Base.metadata.create_all(ENGINE)

# 方便刪除
def drop_db():
    Base.metadata.drop_all(ENGINE)



if __name__ == '__main__':
    # 執行
    create_db()

  • 一對多表建立cookie

    class Book(Base):
   __tablename__ = "book"

   id = Column(Integer, primary_key=True)
   title = Column(String(32), nullable=False)
   publisher_id = Column(Integer, ForeignKey("publisher.id"))
   # 不生成字段創建關係 方便操做
   # 一對多
   publisher = relationship("Publisher", backref="books")
    from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, DateTime
from sqlalchemy import Index, UniqueConstraint, ForeignKey
from sqlalchemy.orm import relationship
import datetime


ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",)

Base = declarative_base()


# ======一對多示例=======
class UserInfo(Base):
    __tablename__ = "user_info"

    id = Column(Integer, primary_key=True)
    name = Column(String(32), index=True, nullable=False)
    email = Column(String(32), unique=True)
    create_time = Column(DateTime, default=datetime.datetime.now)
    # FK字段的創建
    hobby_id = Column(Integer, ForeignKey("hobby.id"))
    # 不生成表結構 方便查詢使用
    hobby = relationship("Hobby", backref="user")

    __table_args__ = (
        UniqueConstraint("id", "name", name="uni_id_name"),
        Index("name", "email")
    )


class Hobby(Base):
    __tablename__ = "hobby"

    id = Column(Integer, primary_key=True)
    title = Column(String(32), default="碼代碼")




def create_db():
    Base.metadata.create_all(ENGINE)


def drop_db():
    Base.metadata.drop_all(ENGINE)



if __name__ == '__main__':
    create_db()
    # drop_db()

  • 多對對建立

    • 第三張表本身生成

      class Book(Base):
   __tablename__ = "book"

   id = Column(Integer, primary_key=True)
   title = Column(String(32), nullable=False)
   publisher_id = Column(Integer, ForeignKey("publisher.id"))
   # 不生成字段創建關係 方便操做
   # 一對多
   publisher = relationship("Publisher", backref="books")
   # 多對多
   tags = relationship("Tag", secondary="book2tag", backref="books")
class Book2Tag(Base):
   __tablename__ = "book2tag"

   id = Column(Integer, primary_key=True)
   book_id = Column(Integer, ForeignKey("book.id"))
   tag_id = Column(Integer, ForeignKey("tag.id"))
      from sqlalchemy import create_engine
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy import Column, Integer, String, DateTime
from sqlalchemy import Index, UniqueConstraint, ForeignKey
from sqlalchemy.orm import relationship
import datetime


ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",)

Base = declarative_base()


# ======多對多示例=======
class Book(Base):
    __tablename__ = "book"

    id = Column(Integer, primary_key=True)
    title = Column(String(32))
    # 不生成表字段 僅用於查詢方便
    tags = relationship("Tag", secondary="book2tag", backref="books")


class Tag(Base):
    __tablename__ = "tag"

    id = Column(Integer, primary_key=True)
    title = Column(String(32))


class Book2Tag(Base):
    __tablename__ = "book2tag"

    id = Column(Integer, primary_key=True)
    book_id = Column(Integer, ForeignKey("book.id"))
    tag_id = Column(Integer, ForeignKey("tag.id"))


def create_db():
    Base.metadata.create_all(ENGINE)

def drop_db():
    Base.metadata.drop_all(ENGINE)

if __name__ == '__main__':
    create_db()
    # drop_db()

    • 建立表命令

      Base.metadata.create_all(conn) # conn是鏈接池對象

對數據庫表的操做(增刪改查)

  • 建立管理器

    from sqlalchemy.orm import sessionmaker, scoped_session
Session = sessionmaker(bind=conn)
# 線程安全 根本本地線程會使用一個session
session = scoped_session(Session)
    from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session
from models_demo import Tag


ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",)

Session = sessionmaker(bind=ENGINE)

# 每次執行數據庫操做的時候，都須要建立一個session

# 線程安全，基於本地線程實現每一個線程用同一個session


session = scoped_session(Session)

# =======執行ORM操做==========
tag_obj = Tag(title="SQLAlchemy")
# 添加
session.add(tag_obj)
# 提交
session.commit()
# 關閉session
session.close()

  • 基本增刪改查

    from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker, scoped_session
from models_demo import Tag, UserInfo
import threading


ENGINE = create_engine("mysql+pymysql://root:root1234@127.0.0.1:3306/code_record?charset=utf8",)

Session = sessionmaker(bind=ENGINE)

# 每次執行數據庫操做的時候，都須要建立一個session
session = Session()
session = scoped_session(Session)

# ============添加============
# tag_obj = Tag(title="SQLAlchemy")
# # 添加
# session.add(tag_obj)
# session.add_all([
#     Tag(title="Python"),
#     Tag(title="Django"),
# ])
# # 提交
# session.commit()
# # 關閉session
# session.close()

# ============基礎查詢============
# ret1 = session.query(Tag).all()
# ret2 = session.query(Tag).filter(Tag.title == "Python").all()
# ret3 = session.query(Tag).filter_by(title="Python").all()
# ret4 = session.query(Tag).filter_by(title="Python").first()
# print(ret1, ret2, ret3, ret4)

# ============刪除===========
# session.query(Tag).filter_by(id=1).delete()
# session.commit()

# ===========修改===========
session.query(Tag).filter_by(id=22).update({Tag.title: "LOL"})
session.query(Tag).filter_by(id=23).update({"title": "王者毒藥"})
session.query(Tag).filter_by(id=24).update({"title": Tag.title + "~"}, synchronize_session=False)
# synchronize_session="evaluate" 默認值進行數字加減
session.commit()

  • 經常使用操做

    # 條件查詢
ret1 = session.query(Tag).filter_by(id=22).first()
ret2 = session.query(Tag).filter(Tag.id > 1, Tag.title == "LOL").all()
ret3 = session.query(Tag).filter(Tag.id.between(22, 24)).all()
ret4 = session.query(Tag).filter(~Tag.id.in_([22, 24])).first()
from sqlalchemy import and_, or_
ret5 = session.query(Tag).filter(and_(Tag.id > 1, Tag.title == "LOL")).first()
ret6 = session.query(Tag).filter(or_(Tag.id > 1, Tag.title == "LOL")).first()
ret7 = session.query(Tag).filter(or_(
    Tag.id>1,
    and_(Tag.id>3, Tag.title=="LOL")
)).all()
# 通配符
ret8 = session.query(Tag).filter(Tag.title.like("L%")).all()
ret9 = session.query(Tag).filter(~Tag.title.like("L%")).all()
# 限制
ret10 = session.query(Tag).filter(~Tag.title.like("L%")).all()[1:2]
# 排序
ret11 = session.query(Tag).order_by(Tag.id.desc()).all()  # 倒序
ret12 = session.query(Tag).order_by(Tag.id.asc()).all()  # 正序
# 分組
ret13 = session.query(Tag.test).group_by(Tag.test).all()
# 聚合函數
from sqlalchemy.sql import func
ret14 = session.query(
    func.max(Tag.id),
    func.sum(Tag.test),
    func.min(Tag.id)
).group_by(Tag.title).having(func.max(Tag.id > 22)).all()
# 連表
ret15 = session.query(UserInfo, Hobby).filter(UserInfo.hobby_id == Hobby.id).all()
# print(ret15) 獲得一個列表套元組 元組裏是兩個對象
ret16 = session.query(UserInfo).join(Hobby).all()
# print(ret16) 獲得列表裏面是前一個對象
# 至關於inner join
# for i in ret16:
#     # print(i[0].name, i[1].title)
#     print(i.hobby.title)
ret17 = session.query(Hobby).join(UserInfo, isouter=True).all()
ret17_1 = session.query(UserInfo).join(Hobby, isouter=True).all()
ret18 = session.query(Hobby).outerjoin(UserInfo).all()
ret18_1 = session.query(UserInfo).outerjoin(Hobby).all()
# 至關於left join
print(ret17)
print(ret17_1)
print(ret18)
print(ret18_1)

  • 基於relationship的Fk

    # 基於relationship的FK
# 添加
user_obj = UserInfo(name="提莫", hobby=Hobby(title="種蘑菇"))
session.add(user_obj)

hobby = Hobby(title="彈奏一曲")
hobby.user = [UserInfo(name="琴女"), UserInfo(name="妹紙")]
session.add(hobby)
session.commit()

# 基於relationship的正向查詢
user_obj_1 = session.query(UserInfo).first()
print(user_obj_1.name)
print(user_obj_1.hobby.title)

# 基於relationship的反向查詢
hb = session.query(Hobby).first()
print(hb.title)
for i in hb.user:
    print(i.name)

session.close()

  • 基於relationship的M2M

    # 添加
book_obj = Book(title="Python源碼剖析")
tag_obj = Tag(title="Python")
b2t = Book2Tag(book_id=book_obj.id, tag_id=tag_obj.id)
session.add_all([
    book_obj,
    tag_obj,
    b2t,
])
session.commit()

#  上面有坑哦~~~~
book = Book(title="測試")
book.tags = [Tag(title="測試標籤1"), Tag(title="測試標籤2")]
session.add(book)
session.commit()

tag = Tag(title="LOL")
tag.books = [Book(title="大龍刷新時間"), Book(title="小龍刷新時間")]
session.add(tag)
session.commit()

# 基於relationship的正向查詢
book_obj = session.query(Book).filter_by(id=4).first()
print(book_obj.title)
print(book_obj.tags)
# 基於relationship的反向查詢
tag_obj = session.query(Tag).first()
print(tag_obj.title)
print(tag_obj.books)

Flask_Script

  • 下載

    pip install flask-script

  • 導入

    from flask_demo import create_app
from flask_script import Manager

  • 實例化

    app = create_app()
# 實例化
manager = Manager(app)

if __name__ == '__main__':
   # app.run()
   manager.run()

  • 自定義的命令

    1. 位置傳參

      @manager.command
   def mycommad(arg):
        prin(arg)
    # python manange.py my_command 123

    2. 關鍵字

      @manager.option('-n','--name', dest='name')
@manager.option('-u','--url', dest='url')
def cmd(name, url):
   print(name, url)
# python manager.py cmd -n xiatian -u www.xxx

      詳細用法:https://www.cnblogs.com/buyisan/p/8270283.html

Flask-Migrate

  • !!! 依賴flask-script

  • 下載

    pip install flask-migrate

  • 導入

    from flask_Migrate import Migrate, MigrateCommand

  • 實例化

    Migrate(app)

manager.add_command('db', MigrateCommand)
"""
  python manager.py db init
  python manager.py db migrate # 類型於makemigrations
  python manager.py db uprade  # migrate
"""
師博客:

https://www.cnblogs.com/GGGG-XXXX/articles/9447619.html

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