flask-cache的使用
1. 安装 pip install flask-caching
2. 初始化 cache = Cache(config={'CACHE_TYPE':'redis'}) cache.init_app(app=app)
缓存视图函数
def make_cache_key():
return request.url
@demo.route('/paginatestudent/')
@cache.cached(timeout=10, key_prefix=make_cache_key)
def paginate_student():
print('请求数据了')
page_num = int(request.args['page_num'])
per_page = 5
pagination = Student.query.paginate(page=page_num, per_page=per_page)
return render_template('index.html', pagination=pagination)
缓存数据
def get_all_students():
# 一上来就从缓存里查找，看有没有数据
students = cache.get('students')
# 如果缓存里没有数据，查询数据库，并且把查询到的结果写入到缓存里
if not students:
print('没有缓存数据，查询数据库')
students = Student.query.all()
cache.set('students', students, timeout=10)
return render_template('ShowStudents.html', students=students)
init.py
from flask import Flask
from App.ext import init_ext
from App.settings import Config
from App.views.demo import demo
def create_app():
app = Flask(__name__)
app.config.from_object(Config)
init_ext(app=app)
app.register_blueprint(blueprint=demo)
return app
ext.py
from flask_bootstrap import Bootstrap
from flask_cache import Cache
from flask_debugtoolbar import DebugToolbarExtension
from flask_session import Session
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
db = SQLAlchemy()
cache = Cache(config={'CACHE_TYPE': 'redis'})
def init_ext(app):
Session(app)
db.init_app(app=app)
migrate = Migrate(app=app, db=db)
Bootstrap(app)
toolbar = DebugToolbarExtension(app)
cache.init_app(app=app)
settings.py
class Config:
SESSION_TYPE = 'redis'
SQLALCHEMY_DATABASE_URI = 'mysql+pymysql://root:[email protected]:3306/day04'
SQLALCHEMY_TRACK_MODIFICATIONS = False
DEBUG = False # 如果要使用Flask-DebugToolbar需要打开DEBUG开关
SECRET_KEY = '23o43iokfjljhotjoJfojtg' # Flask-DebugToolbar必须要配置SECRET_KEY
manager.py
from flask_migrate import MigrateCommand
from flask_script import Manager
from App import create_app
app = create_app()
manager = Manager(app)
manager.add_command('db',MigrateCommand)
if __name__ == '__main__':
manager.run()
models.py
from App.ext import db
class Student(db.Model):
id = db.Column(db.Integer, primary_key=True, autoincrement=True)
s_name = db.Column(db.String(16), nullable=False)
s_age = db.Column(db.Integer, nullable=False, default=10)
s_score = db.Column(db.Float, nullable=False, default=0)
views.py
import random
import time
from flask import Blueprint, render_template, request, current_app, g, abort
from App.ext import db, cache
from App.models import Student
demo = Blueprint('demo', __name__)
@demo.route('/')
def index():
return render_template('index.html')
@demo.route('/addstudents/')
def add_studnets():
students = []
for i in range(20):
student = Student()
num = random.randrange(20, 40)
student.s_name = '张三%d' % num
student.s_age = num
student.s_score = num * 2
students.append(student)
db.session.add_all(students)
db.session.commit()
return '批量添加成功'
@demo.route('/testglobal/')
def test_global():
# 在代码里如果要获取配置项，需要使用current_app拿到app对象，然后再获取config
# print(current_app.config)
# global test_flag
value = request.args['test_flag']
# test_flag = value
g.test_flag = value
if value == '200':
time.sleep(10)
print('睡会儿')
return g.test_flag
# test_flag = '100'
def make_cache_key():
page_num = request.args['page_num']
return request.remote_addr + 'page_num=' + page_num
@demo.route('/paginatestudent/')
@cache.cached(timeout=10, key_prefix=make_cache_key)
def paginate_student():
print('请求数据了')
page_num = int(request.args['page_num'])
per_page = 5
pagination = Student.query.paginate(page=page_num, per_page=per_page)
# students = pagination.items
# print(pagination.pages)
return render_template('index.html', pagination=pagination)
@demo.route('/getallstudents/')
def get_all_students():
# 一上来就从缓存里查找，看有没有数据
students = cache.get('students')
# 如果缓存里没有数据，查询数据库，并且把查询到的结果写入到缓存里
if not students:
print('没有缓存数据，查询数据库')
students = Student.query.all()
cache.set('students', students, timeout=10)
return render_template('ShowStudents.html', students=students)
@demo.before_request
def handle_before():
# print('请求之前')
# 先从缓存里查询次数
count = cache.get('count') or 1
# 如果次数大于10,直接不让用户再继续了
if count >= 10:
# return '5秒钟以内只能刷新十次'
abort(404)
count += 1
cache.set('count', count, timeout=5)
print(type(request.user_agent))
print(request.user_agent)
if not request.user_agent:
return '爬虫别爬了'
index.html
{% extends '/bootstrap/base.html' %}
{% block navbar %}
{% endblock %}
{% block content %}
{% endblock %}
IMG_0687.jpg