flask基础

flask基础

文章目录

• 简单使用
• POST/GET及Session
• config配置
• jsonify
• 操作session
• 请求扩展
• 用redis缓存session

---

简单使用

日常Hello World

from flask import Flask

app = Flask(__name__)


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

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

from flask import Flask, request, render_template, redirect

app = Flask(__name__)


@app.route("/")
def index():
    # print(request.path)
   # return render_template("./index.html")
    return redirect("http://www.baidu.com")
if __name__=="__main__":
    app.run()

POST/GET及Session

from flask import Flask, request, render_template, redirect, session, url_for

app = Flask(__name__)
app.debug = True
app.secret_key = "djhwkjdhakjhdwkj"

USERS = {
    1: {"name": "张三", "age": 18, "gender": "男", "text": "道路千万条"},
    2: {"name": "李四", "age": 28, "gender": "男", "text": "安全第一条"},
    3: {"name": "王五", "age": 18, "gender": "女", "text": "行车不规范"}
}

# endpoint用于反向解析 默认为函数名字
@app.route("/login", methods=["GET", "POST"], endpoint="log")
def login():
    if request.method == "GET":
        return render_template("login.html")
    else:
        # post提交过来的数据放到form中
        # get提交过来的数据query_string中
        user = request.form.get("user")
        pwd = request.form.get("pwd")
        if user == "sweet" and pwd == "123":
            # 往session中放入key和value
            session["user_info"] = user
            return redirect("/index")
        else:
            return render_template("login.html", error="用户名或密码错误")


@app.route("/index", methods=["GET"])
def index():
    user = session.get("user_info")
    if not user:
        url = url_for("log")
        return redirect(url)

    return render_template("index.html", user_dict=USERS)


@app.route("/detail/<int:id>", methods=["GET"])
def detail(id):
    user = session.get("user_info")
    if not user:
        return redirect("/login")

    return render_template("detail.html", info=USERS.get(id))


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

config配置

from flask import Flask

app = Flask(__name__)

class Config(object):
    DEBUG = False

# 指定配置文件类
app.config.from_object(Config)
# app.config.from_object("settings.Config")
# app.config.from_pyfile("settings.py") # 指定配置文件

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

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

jsonify

from flask import Flask,render_template,session,make_response,jsonify

app = Flask(__name__)


@app.route("/")
def index():
    re = make_response(jsonify({"123":22}))
    re.set_cookie("aa", "bb")
    return re

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

操作session

from flask import Flask, session

app = Flask(__name__)

app.secret_key = "kjadkjwkld"
app.config["SESSION_COOKIE_NAME"] = "xxx"

@app.route("/")
def index():

    session["xx"] = "123"
    return "index"

@app.route("/get_session")
def get():

    return session["xx"]

@app.route("/del_session")
def delete_session():

    session.pop("xx")
    return "删除成功"

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

请求扩展

from flask import Flask, request, session, redirect

app = Flask(__name__)
app.secret_key = "uiahwduihawui"

# 请求前
@app.before_request
def process_request(*args, **kwargs):
    print("before执行")
    if request.path == "/login":
        return None
    user = session.get("user_info")
    if user:
        return None
    return redirect("/login")

@app.after_request
def process_response(response):
    print("最后")
    return response

@app.route("/", methods=["GET", "POST"])
def index():
    print("index")
    a = 1 / 0  # 引发异常
    return "index"

@app.route("/login")
def login():
    session["user_info"] = "123"
    return "OK"

# 出错后
@app.errorhandler(404)
def err_404(arg):
    print(arg)
    return "404错误"

@app.errorhandler(500)
def err_500(arg):
    print(arg)
    return "test.html"

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

用redis缓存session

from flask import Flask, make_response, session
from flask_session import RedisSessionInterface
import redis

app = Flask(__name__)

conn = redis.Redis(host="127.0.0.1", port=6379)
app.session_interface = RedisSessionInterface(conn, "whb")


@app.route("/", methods=["POST", "GET"])
def index():
    re = make_response("index")
    return re

if __name__=="__main__":

    app.run()