Flask一：安装初始,return方式,Request,Jinja2,session

一：安装和初始

1.Flask 安装 + 启动from flask import Flaskapp = Flask(__name__) # 实例化flask对象 # __name__ 多app应用，分区实例在哪个文件中app.run()高级启动:from flask import Flaskapp = Flask(__name__)@app.route("/") # app中的rotue装饰器def home(): # 视图函数return "Hello World!"app.run()

二： Render, Redirect HttpResponse

2.Flask Response1.HttpResponse("HelloWorld") "HelloWorld" 返回字符串from flask import render_template 默认存放路径 templates2.render("模板路径") render_template 返回模板from flask import redirect 重定向3.redirect("/") Flask 中的返回特殊封装 2个1.jsonify 转换标准JSON格式响应头中加入 Content-type:application/json在Flask 1.1.1 版本中 加入了 直接返回字典 可以不再使用jsonify了2.send_file 发送文件打开并返回文件内容,自动识别文件类型,响应头中加入Content-type:文件类型 # Content-Type: audio/mpegps:当浏览器无法识别Content-type时,会下载文件# 大的视频文件是 分段式请求 # 打开并返回文件内容，自动识别文件类型，content-type：文件类型# Ps:# 浏览器无法识别content-type时，都以下载返回。 识别的话，直接打开 from flask import Flask, render_template, redirect, jsonify, send_file# Alt + 回车 快速的导入模块app = Flask(__name__) # 实例化flask对象 # __name__ 多app应用，分区实例在哪个文件中app.config["DEBUG"] = True # 能够随时更改自动重启，不加的话每次更改代码需要手动重启@app.route("/") # app中的rotue装饰器 def home(): # 视图函数# return 1# TypeError: The view function did not return a valid response.# The return type must be a string, dict, tuple, Response instance, or WSGI callable, but it was a int.return "home"@app.route("/index") def index():return render_template("index.html")@app.route("/reback") def reback():return redirect('/index')@app.route("/json") def my_jsonify():# return jsonify({"a":1})return {"k": "v"}@app.route("/myfile") def my_file():# return send_file('1chushi.py')# return send_file('1.jpg')return send_file('ss.mp3')# 传文件 # 不管video还是audio都是显示 Audio app.run()

三：Request

3.Flask Request 假登录 405 请求方式不被允许 - GET请求可以 POST请求 405 Method Not Allowed Form表单 - FormData f orm - 表单from flask import request 公共对象1.request.form 获取FormData中的数据 - Form表单 2.request.args # 获取URL中的参数 3.request.files # 获取FormData中的文件数据print(request.url) # 获取访问路径 print(request.method) # 获取请求方式 print(request.path) # 路由地址 /login print(request.values) # Form 和 Args 中的数据 # 综合获取 X print(request.args.get("id")) # 获取URL中的参数 print(request.args["id"]) # 获取URL中的参数 print(request.args.to_dict()) # 获取URL中的参数 转换成 字典print(request.environ) # 获取请求原始信息 print(request.base_url) # 获取URL头,不包含参数print(request.json) # 毁三观 1 请求头中 Content-type:application/json 数据序列化 request.json print(request.data) # 毁三观 2 请求头中 Content-type 不包含 Form or dataprint(request.headers) # 请求头中的数据

3.1：request.py

from flask import Flask, render_template, request import osapp = Flask(__name__) app.config["DEBUG"] = True # 能够随时更改自动重启，不加的话每次更改代码需要手动重启@app.route("/login", methods=["POST", "GET"]) def login():if request.method == "GET":print(request.url) # 获取访问路径# request.url: http://127.0.0.1:5000/login# request.url: http://127.0.0.1:5000/login?id=1print(request.method) # 获取请求方式# GET# GETprint(request.path) # 路由地址 /login# /login# /loginprint(request.values) # 可以获取URL中的参数 也可以获取 FormData中的数据# 综合获取 ，可以获取url 和 formdata的数据# CombinedMultiDict([ImmutableMultiDict([]), ImmutableMultiDict([])])# CombinedMultiDict([ImmutableMultiDict([('id', '1')]), ImmutableMultiDict([])])print(request.args)# ImmutableMultiDict([('id', '1')])print(request.args.to_dict()) # 获取URL中的参数 转换成 字典# {}# {'id': '1'}print(request.args.get("id")) # 获取URL中的参数# None 没有参数的时候就是None# 1# print(request.args["id"]) # 获取URL中的参数# 1# 字典索引取不到值的时候 ，会出现keyerrorprint(request.environ) # 获取请求原始信息# {'wsgi.version': (1, 0), 'wsgi.url_scheme': 'http', 'wsgi.input': <_io.BufferedReader name=1140>, 'wsgi.errors': <_io.TextIOWrapper name='<stderr>' mode='w' encoding='UTF-8'>, 'wsgi.multithread': True, 'wsgi.multiprocess': False, 'wsgi.run_once': False, 'werkzeug.server.shutdown': <function WSGIRequestHandler.make_environ.<locals>.shutdown_server at 0x000001F2C1CD8378>, 'SERVER_SOFTWARE': 'Werkzeug/0.15.4', 'REQUEST_METHOD': 'GET', 'SCRIPT_NAME': '', 'PATH_INFO': '/login', 'QUERY_STRING': '', 'REQUEST_URI': '/login', 'RAW_URI': '/login', 'REMOTE_ADDR': '127.0.0.1', 'REMOTE_PORT': 14611, 'SERVER_NAME': '127.0.0.1', 'SERVER_PORT': '5000', 'SERVER_PROTOCOL': 'HTTP/1.1', 'HTTP_HOST': '127.0.0.1:5000', 'HTTP_CONNECTION': 'keep-alive', 'HTTP_CACHE_CONTROL': 'max-age=0', 'HTTP_UPGRADE_INSECURE_REQUESTS': '1', 'HTTP_USER_AGENT': 'Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36', 'HTTP_ACCEPT': 'text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8', 'HTTP_ACCEPT_ENCODING': 'gzip, deflate, br', 'HTTP_ACCEPT_LANGUAGE': 'zh-CN,zh;q=0.9,en;q=0.8', 'HTTP_COOKIE': 'sessionid=wnuu61vo39ha2rnhjly8tturem306js3; csrftoken=dBlvd2yERl2dy9Oe7JoPLWer7aaOf35nx83lvoruaY0NOkl3T747KlIo5YwZ7026', 'werkzeug.request': <Request 'http://127.0.0.1:5000/login' [GET]>}print(request.base_url) # 获取URL头,不包含参数# http://127.0.0.1:5000/loginprint(request.json) # 毁三观 1 请求头中 Content-type:application/json 数据序列化 request.json# Noneprint(request.data) # 毁三观 2 请求头中 Content-type 不包含 Form or data# b''print(request.headers) # 请求头中的数据# Host: 127.0.0.1:5000# Connection: keep-alive# Cache-Control: max-age=0# Upgrade-Insecure-Requests: 1# User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36# Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8# Accept-Encoding: gzip, deflate, br# Accept-Language: zh-CN,zh;q=0.9,en;q=0.8# Cookie: sessionid=wnuu61vo39ha2rnhjly8tturem306js3; csrftoken=dBlvd2yERl2dy9Oe7JoPLWer7aaOf35nx83lvoruaY0NOkl3T747KlIo5YwZ7026return render_template("login.html")if request.method == "POST":print(request.method)# POSTprint(request.form)# Multidict 多重字典,得到字典套列表套元组的类型# ImmutableMultiDict([('username', '123'), ('pwd', '456')])print(request.form.to_dict())# {'username': '123', 'pwd': '456'}print(request.values) # 可以获取URL中的参数 也可以获取 FormData中的数据# CombinedMultiDict([ImmutableMultiDict([]), ImmutableMultiDict([('username', '123'), ('pwd', '456')])])print(request.values.to_dict())# {'username': '123', 'pwd': '456'}print(request.json) # 毁三观 1 请求头中 Content-type:application/json 数据序列化 request.json# Noneprint(request.data) # 毁三观 2 请求头中 Content-type 不包含 Form or data 原始请求体数据# b''print(request.headers)# Host: 127.0.0.1:5000# Connection: keep-alive# Content-Length: 235# Cache-Control: max-age=0# Origin: http://127.0.0.1:5000# Upgrade-Insecure-Requests: 1# Content-Type: multipart/form-data; boundary=----WebKitFormBoundary1BWoxZMCbTbU3Koy# User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/70.0.3538.110 Safari/537.36# Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8# Referer: http://127.0.0.1:5000/login# Accept-Encoding: gzip, deflate, br# Accept-Language: zh-CN,zh;q=0.9,en;q=0.8# Cookie: sessionid=wnuu61vo39ha2rnhjly8tturem306js3; csrftoken=dBlvd2yERl2dy9Oe7JoPLWer7aaOf35nx83lvoruaY0NOkl3T747KlIo5YwZ7026# print(request.files.get("my_file"))## my_file = request.files.get("my_file")# # fp = os.path.join("templates",my_file.filename)# my_file.save(my_file.filename)# 获取文件的数据print(request.files)# ImmutableMultiDict([('my_file', <FileStorage: '1.jpg' ('image/jpeg')>)])# 文件只在File 里显示# Form中不包含print(request.files.get("my_file"))# <FileStorage: '1.jpg' ('image/jpeg')>my_file = request.files.get("my_file")# my_file.save(my_file.filename)# 保存到本地的# 可以指定路径 用os模块fq = os.path.join("templates", my_file.filename)my_file.save(fq)username = request.form.get("username")password = request.form["pwd"]# Get 和索引都能拿到值if username == "123" and password == "456":return "登录成功"else:return "登录失败"# 如果包导入的话，if __name__下面不会执行 if __name__ == '__main__':app.run()

3.2：login.html

<!DOCTYPE html> <html lang="zh-CN"> <head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>Title</title><link rel="stylesheet" href="bootstrap-3.3.7-dist/css/bootstrap.min.css"></head> <body><form action="/login" method="post" enctype="multipart/form-data">用户名: <input type="text " name="username">密码: <input type="password" name="pwd"><input type="file" name="my_file"><input type="submit"> </form><script src="jquery-3.4.1.js"></script> <script></script> </body> </html>

四：Jinja2和高级用法

4.Jinja2 {{}} 引用 or 执行 {%%} 逻辑语法 if else for

4.1：jinja2.py

from flask import Flask, render_template,request,redirect,MarkupSTUDENT = {'name': 'Ivan', 'age': 38, 'gender': '中'}STUDENT_LIST = [{'name': 'Sail', 'age': 38, 'gender': '中'},{'name': 'Ivan', 'age': 73, 'gender': '男'},{'name': 'VS', 'age': 84, 'gender': '女'} ]STUDENT_DICT = {1: {'name': 'Sail', 'age': 38, 'gender': '中'},2: {'name': 'Ivan', 'age': 73, 'gender': '男'},3: {'name': 'VS', 'age': 84, 'gender': '女'}, }app = Flask(__name__) app.config["DEBUG"] = True@app.template_global() # 把ab函数传到前端了 def ab(a,b):return a+b@app.route("/jija") def jija():my_in = Markup("<input type='text' name='uname'>")return render_template("jija.html",stu_info=STUDENT,stu_list=STUDENT_LIST,stu_dict=STUDENT_DICT,m=my_in)if __name__ == '__main__':app.run("127.0.0.1", 9999)

4.2：jinja2.html

<!DOCTYPE html> <html lang="zh-CN"> <head><meta charset="UTF-8"><title>Title</title> </head> <body> {{ stu_info }}<table border="1px"><tr><td>name</td><td>age</td><td>gender</td></tr><tr><td>{{ stu_info.name }}</td><td>{{ stu_info.get("age") }}</td><td>{{ stu_info["gender"] }}</td></tr></table><br/>{{ stu_list }}<table border="1px"><tr><td>name</td><td>age</td><td>gender</td></tr>``` {% for foo in stu_list %}<tr><td>{{ foo.name }}</td><td>{{ foo.get("age") }}</td><td>{% if foo["gender"] !="男" and foo["gender"] !="女" %}女{{ foo["gender"] }}{% endif %}</td></tr> {% endfor %} ```</table> <br/>{{ stu_dict }}<table border="1px"><tr><td>id</td><td>name</td><td>age</td><td>gender</td></tr><tr>{% for id,s in stu_dict.items() %}<td>{{ id }}</td><td>{{ s.name }}</td><td>{{ s.get("age") }}</td><td>{{ s["gender"] }}</td></tr>{% endfor %}</table><br/> {{ m }}<br/> {% macro my_input(na,ty) %}<input type="{{ ty }}" name="{{ na }}"> {% endmacro %}{{ my_input("uname","text") }} # macro 需要启动才生产输入框<br/> {#{{ ab(1,2) }}#}</body> </html>

五：session

5.Flask中的Session 不是三方组件 //Flask-Session from flask import sessionsession 交由客户端保管机制 # eyJ1c2VybmFtZSI6IjEyMyJ9.XSVpHA.W0NfiCmW-lsTV0mvQI7mx2mf1Wo # .eJyrViotTi3KS8xNVbJSMjQyVtKBCxhiiBhhiBhjiJhgiJhiiJhBRWoBMFYkPg.XSVsaA.9merwNdTg3ZkZrdTumYRG7x8x7Y # .eJyrViotTi3KS8xNVbJSMjQyVtKBCxhiiBhhiBhjiJhgiJhiiJhBRWoBMFYkPg.XSVsvg.6OqcN7CR6nrT2BtE-w1kBAr3xPo # .eJxNzL0OgCAMBOB36exAoRTjs7jwUzcdNEzGdxckMV1u-e7uhnrJecRdYIG1eqS5pWCB6RccZDGtlQSjIvsRBxtbwZEmN8gZ21czK6JBiamtQhZF_qPAuR-WookH-dQO_WYiPC-8zDp8.XSVtLw.7I-z1bsqiWFln3cipbrVOpEE33g反序列化机制 - 当客户端发起请求 - request 带上 Cookie - Cookie中有session的加密字符串 - Flask 收到Session加密字符串 - 通过secret_key解密session的加密字符串 - 获得 {username:123}序列化机制 - 开启session - session["username"] = uname 先创建一个字典 {username:123} 接下来 通过secret_key + 时间戳 + 签名 加密 形成 # eyJ1c2VybmFtZSI6IjEyMyJ9.XSVpHA.W0NfiCmW-lsTV0mvQI7mx2mf1Wo session的加密字符串

5.1：session.py

from flask import Flask, session, request, render_template, redirectapp = Flask(__name__) app.debug = True app.secret_key = "adfnaskjfnakjs"STUDENT = {'name': 'Old', 'age': 38, 'gender': '中'}STUDENT_LIST = [{'name': 'Old', 'age': 38, 'gender': '中'},{'name': 'Boy', 'age': 73, 'gender': '男'},{'name': 'EDU', 'age': 84, 'gender': '女'} ]STUDENT_DICT = {1: {'name': 'Old', 'age': 38, 'gender': '中'},2: {'name': 'Boy', 'age': 73, 'gender': '男'},3: {'name': 'EDU', 'age': 84, 'gender': '女'}, }@app.route("/login", methods=["POST", "GET"]) def login():if request.method == "GET":return render_template("login.html")uname = request.form.get("username")pwd = request.form.get("pwd")if uname == '123' and pwd == '123':session['username'] = unamereturn "登陆成功"else:return "登录失败"@app.route("/detail") def detail():if session.get("username"):return render_template("jija.html",stu_info=STUDENT,stu_list=STUDENT_LIST,stu_dict=STUDENT_DICT, )else:return redirect("/login")if __name__ == '__main__':app.run("127.0.0.1", 9999)

5.2：login.html

<!DOCTYPE html> <html lang="zh-CN"> <head><meta charset="UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="viewport" content="width=device-width, initial-scale=1"><title>Title</title><link rel="stylesheet" href="bootstrap-3.3.7-dist/css/bootstrap.min.css"></head> <body><form action="/login" method="post" enctype="multipart/form-data">用户名: <input type="text " name="username">密码: <input type="password" name="pwd"><input type="file" name="my_file"><input type="submit"> </form><script src="jquery-3.4.1.js"></script> <script></script> </body> </html>

转载于:https://www.cnblogs.com/Quantum-World/p/11166227.html

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