Flask最基本示例
1. app
# coding:utf-8
from flask import Flask, current_app, redirect, url_for
# 创建Flask的应用程序
# __name__表示当前的模块名字
# 模块名：flask以这个模块所在的目录为总目录，默认这个目录中的static为静态目录，templates为模板目录
app = Flask(__name__)
# app = Flask(__name__,
# static_url_path='/python', # 访问静态资源的url前缀，默认值是static
# static_folder='static', # 静态文件目录，默认就是static
# template_folder='templates', # 模板文件的目录，默认是templates
# )
# 配置参数的使用方式
# 1.使用配置文件
# app.config.from_pyfile("config.cfg")
# 2.使用对象配置参数
# class Config(object):
# DEBUG = True
# ITCAST = "python" # 自用参数
# app.config.from_object(Config)
# 3.直接操作config的字典对象
# app.config["DEBUG"] = True
# 以装饰器形式绑定路由
@app.route('/')
def hello_world():
# 读取配置参数
# 1.直接从全局对象app的config字典中取值
# print (app.config.get('ITCAST',''))
# 2.通过current_app获取参数
# print (current_app.config.get("ITCAST"))
return 'Hello World!'
@app.route("/login")
def login():
# url = "/"
# 使用url_for的函数，通过视图函数的名字找到视图对应的url函数
url = url_for("hello_world")
return redirect(url)
if __name__ == '__main__':
# 通过url_map可以查看整个flask中的路由信息
print (app.url_map)
# 启动flask程序
app.run(debug=True)
# app.run(host="0.0.0.0", port=5000)
2. url
# coding:utf-8
from flask import Flask, current_app, redirect, url_for
# 创建Flask的应用程序
# __name__表示当前的模块名字
# 模块名，flask以这个模块所在的目录为总目录，默认这个目录中的static为静态目录，templates为模板目录
app = Flask(__name__)
# 以装饰器形式绑定路由
@app.route('/')
def hello_world():
return 'Hello World!'
# 通过method限定访问方式
@app.route("/post_only", methods=["GET","POST"])
def post_only():
return "post only page"
# 给同一个url添加不同视图函数，利用method区别
@app.route("/hello", methods=["POST"])
def hello():
return "hello 1"
@app.route("/hello", methods=["GET"])
def hello2():
return "hello 2"
# 给同一个函数添加多个url
@app.route("/hi1")
@app.route("/hi2")
def hi():
return "hi page"
@app.route("/login")
def login():
# url = "/"
# 使用url_for的函数，通过视图函数的名字找到视图对应的url函数
url = url_for("hello_world")
return redirect(url)
if __name__ == '__main__':
# 通过url_map可以查看整个flask中的路由信息
print (app.url_map)
# 启动flask程序
app.run(debug=True)
# app.run(host="0.0.0.0", port=5000)
3. request
# -- coding: utf-8 --
from flask import Flask, request
app = Flask(__name__)
# 接口
# 127.0.0.1:5000/index?city=shenzhen&country=china 查询字符串QueryString
@app.route("/index", methods=["GET", "POST"])
def index():
# request中包含了前端发送过来的所有请求数据
# form和data是用来提取请求体中的参数
# 通过request.form可以直接提取请求体中的表单格式的数据，是一个类字典的对象
# 通过get方法只能拿到多个同名参数的第一个
age = request.form.get("age", "23")
name = request.form.get("name", "zhangsan")
# args是用来提取url中的参数（查询字符串）
city = request.args.get("city")
# 通过getlist方法能拿到多个同名参数
name_list = request.form.getlist("name")
print (request.data)
return "hello name=%s, age=%s, city=%s, name=%s" % (name, age, city, name_list)
# 表单格式数据
# city=value&age=value&gender=value
# file类型，必须给form标签添加 enctype="multipart/form-data"
if __name__ == "__main__":
app.run(debug=True)
4. response
# -- coding: utf-8 --
from flask import Flask, request, abort, Response, make_response
app = Flask(__name__)
@app.route("/index", methods=["GET"])
def index():
# 1.使用元祖，返回自定义的响应信息
# 响应体 状态码 响应头
# return "index page", 400, [("Itcast", "python",), ("City", "shenzhen")]
# return "index page", "666 itcast status", {"Itcast": "python", "City": "shenzhen"}
# return "index page", "666 itcast status"
# 2.使用make_response来构造响应信息
resp = make_response("index page 2")
resp.status = "999 itcast" # 设置状态码
resp.headers['city'] = "sz" # 设置响应头
return resp
if __name__ == "__main__":
app.run(debug=True)
4. upload_file
# -- coding: utf-8 --
from flask import Flask, request
app = Flask(__name__)
@app.route("/upload", methods=["POST"])
def upload():
"""接收前端传送过来的文件"""
file_obj = request.files.get("pic")
if file_obj is None:
# 表示没有发送文件
return "未上传文件"
# 将文件保存到本地
# 1.创建一个文件
# with open("./demo.jpg","wb") as f:
# # 2.向文件内部写内容
# data = file_obj.read()
# f.write(data)
# 直接使用上传的文件对象保存
file_obj.save("./demo1.jpg")
return "上传成功"
if __name__ == "__main__":
app.run(debug=True)
5. cookie
# -- coding: utf-8 --
import json
from flask import Flask, make_response, request
app = Flask(__name__)
@app.route("/set_cookie")
def set_cookie():
resp = make_response("success")
# 设置cookie，默认有效期是临时cookie，浏览器关闭就失效
resp.set_cookie("Itcast", "Python")
resp.set_cookie("Itcast1", "Python1")
# max_age设置有效期，单位：秒
resp.set_cookie("Itcast2", "Python2", max_age=3600)
return resp
@app.route("/get_cookie")
def get_cookie():
c = request.cookies.get("Itcast2")
return c
@app.route("/delete_cookie")
def delete_cookie():
resp = make_response("del success")
resp.delete_cookie("Itcast2")
return resp
if __name__ == "__main__":
app.run(debug=True)
6. session
# -- coding: utf-8 --
import json
from flask import Flask, session
# session_dict = {
# "1":{
#
# },
# "2":{
#
# }
# }
app = Flask(__name__)
# flask的session需要用到的秘钥字符串
app.config["SECRET_KEY"] = "SFJKDFSSDKJEGF"
# flask默认把session保存到了cookie中
@app.route("/login")
def login():
# global session_dict
# session_dict["1"][] =
# 设置session数据
session["name"] = "python"
session["mobile"] = "18697118727"
return "login success"
@app.route("/index")
def index():
# 获取session
name = session.get("name")
return "hello %s" % name
if __name__ == "__main__":
app.run(debug=True)
7. templates
# -- coding: utf-8 --
import json
from flask import Flask, render_template
app = Flask(__name__)
@app.route("/index")
def delete_cookie():
data = {
"name": "python",
"age": 18,
"my_dict": {"city": "sz"},
"my_list": [1, 2, 3, 4, 5],
"my_int": 0
}
return render_template("index.html", **data)
if __name__ == "__main__":
app.run(debug=True)
8. jsonify
# -- coding: utf-8 --
import json
from flask import Flask, jsonify
app = Flask(__name__)
@app.route("/index", methods=["GET"])
def index():
# json就是字符串
data = {
"name": "python",
"age": 18
}
# json_str = json.dumps(data)
# return json_str, 200, {"Content-Type": "application/json"}
# jsonify帮助转为json数据，并设置响应头 Content-Type为 application/json
# return jsonify(data)
return jsonify(city="sz", country="china")
if __name__ == "__main__":
app.run(debug=True)
9. abort
# -- coding: utf-8 --
from flask import Flask, request, abort, Response
app = Flask(__name__)
@app.route("/login", methods=["GET"])
def login():
# uname = request.form.get("uname")
# upwd = request.form.get("upwd")
uname = ""
upwd = ""
if uname != "zhangsan" and upwd != "admin":
# 使用abort函数可以立即终止视图函数的执行
# 并可以返回给前端特定的信息
# 1.传递状态码信息，必须是标准的http状态码
abort(404)
# 2.传递响应体信息
# resp = Response("login failed")
# abort(resp)
return "login success"
# 定义错误处理方法
@app.errorhandler(404)
def handle_404_error(err):
"""自定义的处理错误方法"""
# 这个函数的返回值会是前端用户看到的最终结果
return u"出现了404错误，错误信息：%s" % err
if __name__ == "__main__":
app.run(debug=True)
10. converter
# -*- coding:utf-8 -*-
from flask import Flask, current_app, redirect, url_for
from werkzeug.routing import BaseConverter
# 创建Flask的应用程序
# __name__表示当前的模块名字
# 模块名，flask以这个模块所在的目录为总目录，默认这个目录中的static为静态目录，templates为模板目录
app = Flask(__name__)
# 转换器
# 127.0.0.1:5000/goods/123
# @app.route("/goods/")
@app.route("/goods/" ) # 不加转换器类型，默认是普通字符串规则（除了/的字符）
def goods(goods_id):
"""定义的视图函数"""
return "goods detail page %s" % goods_id
# 1.定义自己的转换器
class MobileConverter(BaseConverter):
def __init__(self, url_map):
super(MobileConverter,self).__init__(url_map)
self.regex = r"1[34578]\d{9}"
# 万能正则表达式
class RegexConverter(BaseConverter):
"""自定义转换器类"""
def __init__(self, url_map, regex):
# 调用父类的初始化方法
super(RegexConverter,self).__init__(url_map)
# 将正则表达式的参数保存到对象属性中，flask会使用这个属性来进行路由的正则匹配
self.regex = regex
def to_python(self, value):
print ("to_pathon方法被调用")
# return "abc"
# value是在路径进行正则匹配的时候提取的信息
return value
def to_url(self, value):
"""使用url_for的方法的时候被调用"""
return value
# 2.将自定义的转换器添加到flask的应用中
app.url_map.converters["re"] = RegexConverter
app.url_map.converters["mobile"] = MobileConverter
# 127.0.0.1:5000/send/12334566743
# @app.route("/send/")
@app.route("/send/" )
def send_sms(mobile_num):
return "send sms to %s" % mobile_num
@app.route("/index")
def index():
# /send/18912345678
url = url_for("send_sms",mobile_num="18912345678")
return redirect(url)
if __name__ == '__main__':
# 通过url_map可以查看整个flask中的路由信息
print (app.url_map)
# 启动flask程序
app.run(debug=True)
# app.run(host="0.0.0.0", port=5000)
11. SQLAlchemy
# -- coding: utf-8 --
from flask import Flask, render_template, request, redirect, url_for, jsonify
from flask_wtf import FlaskForm
from wtforms import StringField, SubmitField
from wtforms.validators import DataRequired
from flask_script import Manager
from flask_migrate import Migrate, MigrateCommand
import pymysql
from flask_sqlalchemy import SQLAlchemy
pymysql.install_as_MySQLdb()
app = Flask(__name__)
class Config(object):
# sqlalchemy的配置参数
SQLALCHEMY_DATABASE_URI = "mysql://root:admin123@localhost:3306/author_book"
# 设置sqlalchemy自动跟踪数据库
SQLALCHEMY_TRACK_MODIFICATIONS = True
SECRET_KEY = "DFDSGFGdsgfsgsg"
# 读取配置文件
app.config.from_object(Config)
# 创建sqlalchemy的数据库链接对象
db = SQLAlchemy(app)
# 创建flask脚本管理工具
manager = Manager(app)
# 创建数据库迁移工具对象
Migrate(app,db)
# 向manager对象中添加数据库操作命令
manager.add_command('db', MigrateCommand)
# 定义数据库的模型
class Author(db.Model):
"""作者"""
__tablename__ = "tbl_authors"
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(32), unique=True)
email = db.Column(db.String(32), unique=True)
books = db.relationship('Book', backref="author")
def __repr__(self):
return '' % self.name
class Book(db.Model):
"""书籍"""
__tablename__ = "tbl_books"
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(64),unique=True)
author_id = db.Column(db.Integer, db.ForeignKey('tbl_authors.id'))
def __repr__(self):
return '' % self.name
# 创建表单模型类
class AuthorBookForm(FlaskForm):
"""作者数据表单模型类"""
author_name = StringField(label=u"作者", validators=[DataRequired(u"作者必填")])
book_name = StringField(label=u"书籍", validators=[DataRequired(u"书籍必填")])
submit = SubmitField(label=u"保存")
@app.route("/", methods=['POST', 'GET'])
def index():
# 创建表单对象
form = AuthorBookForm()
# 查询数据库
if form.validate_on_submit():
# 验证表单成功
author_name = form.author_name.data
book_name = form.book_name.data
# 保存数据库
author = Author.query.filter_by(name=author_name).first()
if not author:
author = Author(name=author_name)
db.session.add(author)
db.session.commit()
book = Book.query.filter_by(name=book_name).first()
if not book:
book = Book(name=book_name, author_id=author.id)
# book = Book(name=book_name, author_id=author)
db.session.add(book)
db.session.commit()
authors = Author.query.all()
return render_template("author_book.html", authors=authors, form=form)
# /delete_book?book_id=xxx
@app.route("/delete_book", methods=['POST'])
def delete_book():
"""删除数据"""
# 提取参数(如果前端发生的请求体数据是json格式，get_json会解析成字典)
# get_json要求前端传送的数据的Content-Type: application/json
req_dict = request.get_json()
book_id = req_dict.get("book_id")
# 删除数据
book = Book.query.get(book_id)
db.session.delete(book)
db.session.commit()
return jsonify(code=0, message='OK')
if __name__ == "__main__":
# 通过manager.run启动
manager.run()
# app.run(debug=True)
# db.drop_all()
# db.create_all()
#
# au_xi = Author(name=u"我吃西红柿", email="[email protected]")
# au_qian = Author(name=u"萧潜", email="[email protected]")
# au_san = Author(name=u"唐家三少", email="[email protected]")
# db.session.add_all([au_xi, au_qian, au_san])
# db.session.commit()
#
# bk_xi = Book(name=u"吞噬星空", author_id=au_xi.id)
# bk_xi2 = Book(name=u"寸芒", author_id=au_qian.id)
# bk_qian = Book(name=u"飘渺之旅", author_id=au_qian.id)
# bk_san = Book(name=u"冰火魔厨", author_id=au_san.id)
# db.session.add_all([bk_xi, bk_xi2, bk_qian, bk_san])
# db.session.commit()
# 1、生成迁移文件
python 模块名.py db init
# 2、检查更新迁移文件，-m参数信息可省略不写
python 模块名.py db migrate -m "备注信息"
# 3、更新到数据库
python 模块名.py db upgrade
# 查询历史操作
python 模块名.py db history
# 回退操作
python 模块名.py db downgrade 要退回版本状态码
12. 模块测试
登录
# -- coding: utf-8 --
from flask import Flask, request, jsonify
app = Flask(__name__)
@app.route("/login", methods=["POST"])
def login():
# 接收参数
uname = request.form.get("uname")
upwd = request.form.get("upwd")
# 判断参数
if not all([uname, upwd]):
resp = {
"code": 1,
"message": "invalid params"
}
return jsonify(resp)
if uname == "admin" and upwd == "python":
resp = {
"code": 0,
"message": "login success"
}
return jsonify(resp)
else:
resp = {
"code": 2,
"message": "wrong uname or upwd"
}
return jsonify(resp)
if __name__ == "__main__":
app.run(debug=True)
测试
# -- coding: utf-8 --
import unittest
from login import app
import json
class LoginTest(unittest.TestCase):
"""构造单元测试案例"""
"""构造单元测试案例"""
def setUp(self):
"""在测试之前，先被执行"""
# 创建进行web请求的客户端，使用flask提供的
# 设置flask工作在测试模式下（以下两种方式2选1）
# app.config['TESTING'] = True
app.testing = True
self.client = app.test_client()
def test_empty_user_name_password(self):
"""测试用户名密码不完整的情况"""
# 测试用户名和密码都不传
# 利用client客户端模拟发送请求
ret = self.client.post('/login', data={})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 1)
# 测试只传密码
# 利用client客户端模拟发送请求
ret = self.client.post('/login', data={"upwd": "python"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 1)
# 测试只传用户名
# 利用client客户端模拟发送请求
ret = self.client.post('/login', data={"uname": "admin"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 1)
def test_wrong_user_name_password(self):
"""测试用户名或密码错误"""
# 测试用户名和密码都为错
ret = self.client.post("/login",data={"uname": "iydsff", "upwd": "iughf"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 2)
# 测试用户名错，密码对
ret = self.client.post("/login", data={"uname": "iydsff", "upwd": "python"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 2)
# 测试密码错，用户名对
ret = self.client.post("/login", data={"uname": "admin", "upwd": "sfdf"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 2)
def test_wright_user_name_password(self):
""""测试用户名或密码错误"""
# 测试用户名和密码都正确
ret = self.client.post("/login", data={"uname": "admin", "upwd": "python"})
# ret是视图返回的响应对象,data属性是响应体数据
resp = ret.data
# 因为login视图返回的是json字符串
resp = json.loads(resp)
# 拿到返回值开始断言测试
self.assertIn("code", resp)
self.assertEquals(resp['code'], 0)
if __name__ == "__main__":
unittest.main()