flask学习

Posted 2021-02-17 yinwenjie

特点：

　　短小精悍，可扩展性强

　　依赖wsgi：werkzurg

werkzurg示例：

from werkzeug.wrappers import Request, Response
from werkzeug.serving import run_simple

def run(environ,start_response):

    return [b"asdfasdf"]

if __name__ == ‘__main__‘:

    run_simple(‘localhost‘, 4000, run)

最简单的实现形式

from werkzeug.wrappers import Request, Response

@Request.application
def hello(request):
    return Response(‘Hello World!‘)

if __name__ == ‘__main__‘:
    from werkzeug.serving import run_simple
    run_simple(‘localhost‘, 4000, hello)

正常的内部实现形式

#访问index则可以得到Hello World

from flask import Flask
app = Flask(__name__)

@app.route("/index")
def run():
    return "Hello World"

if __name__ == "__main__":
    app.run()

九行代码实现网页

 

实现一个登陆验证的功能：

from flask import Flask,render_template,request,redirect,session
app = Flask(__name__)    #一般用__name__，但是用其他只要是字符串都行
app.secret_key = "asdfsg"      #给session加密的盐

@app.route("/login",methods=["GET","POST"])
def login():
    if request.method == "GET":
        return render_template("login.html")
    user = request.form.get("user")     #request.args相当于request.GET，request.form相当于request.POST
    pwd = request.form.get("pwd")
    if user=="xxx" and pwd=="xxx":
        session["user"] = user          #flask的session其实是cookie，但是加了密
        return redirect("/index")
    else:
        return render_template("login.html",error="用户名或密码错误")  #或者可以写成**{error:"用户名或密码错误"}

@app.route("/index")    #不写methods默认只接受GET请求
def index():
    user = session.get("user")
    if not user:
        return redirect("/login")
    return render_template("index.html")

if __name__ == "__main__":
    app.run()

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