flask基础
知识点回顾
1、flask依赖wsgi,实现wsgi的模块:wsgiref,werkzeug,uwsgi
2、实例化Flask对象,里面是有参数的
app = Flask(__name__,template_folder='templates',static_url_path='/xxxxxx')
3、两种添加路由的方式
方式一: @app.route('/xxxx') # @decorator def index(): return "Index" 方式二: def index(): return "Index" app.add_url_rule('/xxx', "n1", index) #n1是别名
4、添加路由关系的本质
将url和视图函数封装成一个Rule对象)添加到Flask的url_map字段中
5、Flask中装饰器应用
from flask import Flask,render_template,request,redirect,session app = Flask(__name__) app.secret_key = "sdsfdsgdfgdfgfh" def wrapper(func): def inner(*args,**kwargs): if not session.get("user_info"): return redirect("/login") ret = func(*args,**kwargs) return ret return inner @app.route("/login",methods=["GET","POST"]) def login(): if request.method=="GET": return render_template("login.html") else: # print(request.values) #这个里面什么都有,相当于body username = request.form.get("username") password = request.form.get("password") if username=="haiyan" and password=="123": session["user_info"] = username # session.pop("user_info") #删除session return redirect("/index") else: # return render_template("login.html",**{"msg":"用户名或密码错误"}) return render_template("login.html",msg="用户名或者密码错误") @app.route("/index",methods=["GET","POST"]) @wrapper def index(): # if not session.get("user_info"): # return redirect("/login") return render_template("index.html") if __name__ == '__main__': app.run(debug=True)
5、请求响应相关
- request - request.form #POST请求 - request.args #GET请求 字典形式的 - request.querystring #GET请求,bytes形式的 - response - return render_tempalte() - return redirect() - return "" v = make_response(返回值) #吧返回的值包在了这个函数里面 - session - 存在浏览器上,并且是加密的 - 依赖于:secret_key
flask配置文件
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1 flask中的配置文件是一个flask.config.Config对象(继承字典),默认配置为: 2 { 3 'DEBUG': get_debug_flag(default=False), 是否开启Debug模式 4 'TESTING': False, 是否开启测试模式 5 'PROPAGATE_EXCEPTIONS': None, 6 'PRESERVE_CONTEXT_ON_EXCEPTION': None, 7 'SECRET_KEY': None, 8 'PERMANENT_SESSION_LIFETIME': timedelta(days=31), 9 'USE_X_SENDFILE': False, 10 'LOGGER_NAME': None, 11 'LOGGER_HANDLER_POLICY': 'always', 12 'SERVER_NAME': None, 13 'APPLICATION_ROOT': None, 14 'SESSION_COOKIE_NAME': 'session', 15 'SESSION_COOKIE_DOMAIN': None, 16 'SESSION_COOKIE_PATH': None, 17 'SESSION_COOKIE_HTTPONLY': True, 18 'SESSION_COOKIE_SECURE': False, 19 'SESSION_REFRESH_EACH_REQUEST': True, 20 'MAX_CONTENT_LENGTH': None, 21 'SEND_FILE_MAX_AGE_DEFAULT': timedelta(hours=12), 22 'TRAP_BAD_REQUEST_ERRORS': False, 23 'TRAP_HTTP_EXCEPTIONS': False, 24 'EXPLAIN_TEMPLATE_LOADING': False, 25 'PREFERRED_URL_SCHEME': 'http', 26 'JSON_AS_ASCII': True, 27 'JSON_SORT_KEYS': True, 28 'JSONIFY_PRETTYPRINT_REGULAR': True, 29 'JSONIFY_MIMETYPE': 'application/json', 30 'TEMPLATES_AUTO_RELOAD': None, 31 } 32 33 方式一: 34 app.config['DEBUG'] = True 35 36 PS: 由于Config对象本质上是字典,所以还可以使用app.config.update(...) 37 38 方式二: 39 app.config.from_pyfile("python文件名称") 40 如: 41 settings.py 42 DEBUG = True 43 44 app.config.from_pyfile("settings.py") 45 46 app.config.from_envvar("环境变量名称") 47 环境变量的值为python文件名称名称,内部调用from_pyfile方法 48 49 50 app.config.from_json("json文件名称") 51 JSON文件名称,必须是json格式,因为内部会执行json.loads 52 53 app.config.from_mapping({'DEBUG':True}) 54 字典格式 55 56 app.config.from_object("python类或类的路径") 57 58 app.config.from_object('pro_flask.settings.TestingConfig') 59 60 settings.py 61 62 class Config(object): 63 DEBUG = False 64 TESTING = False 65 DATABASE_URI = 'sqlite://:memory:' 66 67 class ProductionConfig(Config): 68 DATABASE_URI = 'mysql://user@localhost/foo' 69 70 class DevelopmentConfig(Config): 71 DEBUG = True 72 73 class TestingConfig(Config): 74 TESTING = True 75 76 PS: 从sys.path中已经存在路径开始写 77 78 79 PS: settings.py文件默认路径要放在程序root_path目录,如果instance_relative_config为True,则就是instance_path目录
一、路由系统
1、可传入参数:
@app.route('/user/<username>') #常用的 不加参数的时候默认是字符串形式的 @app.route('/post/<int:post_id>') #常用的 #指定int,说明是整型的 @app.route('/post/<float:post_id>') @app.route('/post/<path:path>') @app.route('/login', methods=['GET', 'POST'])
常用路由系统有以上五种,所有的路由系统都是基于一下对应关系来处理:
DEFAULT_CONVERTERS = { 'default': UnicodeConverter, 'string': UnicodeConverter, 'any': AnyConverter, 'path': PathConverter, 'int': IntegerConverter, 'float': FloatConverter, 'uuid': UUIDConverter, }
2、反向生成URL: url_for
endpoint("name") #别名,相当于django中的name
反向解析需要导入:
from flask import Flask, url_for
@app.route('/index',endpoint="xxx") #endpoint是别名 def index(): v = url_for("xxx") print(v) return "index" @app.route('/zzz/<int:nid>',endpoint="aaa") #endpoint是别名 def zzz(nid): v = url_for("aaa",nid=nid) print(v) return "index2"
3、@app.route和app.add_url_rule参数
@app.route和app.add_url_rule参数: rule, URL规则 view_func, 视图函数名称 defaults=None, 默认值,当URL中无参数,函数需要参数时,使用defaults={'k':'v'}为函数提供参数 endpoint=None, 名称,用于反向生成URL,即: url_for('名称') methods=None, 允许的请求方式,如:["GET","POST"] strict_slashes=None, 对URL最后的 / 符号是否严格要求, 如: @app.route('/index',strict_slashes=False), 访问 http://www.xx.com/index/ 或 http://www.xx.com/index均可 @app.route('/index',strict_slashes=True) 仅访问 http://www.xx.com/index redirect_to=None, 重定向到指定地址 如: @app.route('/index/<int:nid>', redirect_to='/home/<nid>') 或 def func(adapter, nid): return "/home/888" @app.route('/index/<int:nid>', redirect_to=func) subdomain=None, 子域名访问 from flask import Flask, views, url_for app = Flask(import_name=__name__) app.config['SERVER_NAME'] = 'haiyan.com:5000' @app.route("/", subdomain="admin") def static_index(): """Flask supports static subdomains This is available at static.your-domain.tld""" return "admin.xxx.com" #动态生成 @app.route("/dynamic", subdomain="<username>") def username_index(username): """Dynamic subdomains are also supported Try going to user1.your-domain.tld/dynamic""" return username + ".your-domain.tld" if __name__ == '__main__': app.run() 所有的域名都得与IP做一个域名解析: 如果你想通过域名去访问,有两种解决方式: 方式一: 1、租一个域名 haiyan.lalala 2、租一个公网IP 49.8.5.62 3、域名解析: haiyan.com 49.8.5.62 4、吧代码放在49.8.5.62这个服务器上,程序运行起来 用户可以通过IP进行访问 方式二:如果是自己测试用的就可以用这种方式。先在自己本地的文件中找 C:\Windows\System32\drivers\etc 找到HOST,修改配置 然后吧域名修改成自己的本地服务器127.0.0.1 加上配置:app.config["SERVER_NAME"] = "haiyan.com:5000"
练习以上的参数
redirect_to:直接重定向,原url有参数时,跳转是也得传参,注意:不用加类型
#/old
@app.route('/old/<int:nid>',redirect_to="/new/<nid>")
def old(nid):
return "old"
# /new
@app.route('/new/<int:nid>')
def new(nid):
return "new"
# ============对url最后的/符号是否严格要求========= @app.route('/test',strict_slashes=True) #当为True时,url后面必须不加斜杠 def test(): return "aaaaaaaa" @app.route('/test',strict_slashes=False) #当为False时,url上加不加斜杠都行 def test(): return "aaaaaaaa"
# =============== 子域名访问============ @app.route("/static_index", subdomain="admin") def static_index(): return "admin.bjg.com" # ===========动态生成子域名=========== @app.route("/index",subdomain='<xxxxx>') def index(xxxxx): return "%s.bjg.com" %(xxxxx,)
扩展Flask的路由系统,让他支持正则,这个类必须这样写,必须去继承BaseConverter
from flask import Flask,url_for app = Flask(__name__) # 定义转换的类 from werkzeug.routing import BaseConverter class RegexConverter(BaseConverter): """ 自定义URL匹配正则表达式 """ def __init__(self, map, regex): super(RegexConverter, self).__init__(map) self.regex = regex def to_python(self, value): """ 路由匹配时,匹配成功后传递给视图函数中参数的值 :param value: :return: """ return int(value) def to_url(self, value): """ 使用url_for反向生成URL时,传递的参数经过该方法处理,返回的值用于生成URL中的参数 :param value: :return: """ val = super(RegexConverter, self).to_url(value) return val # 添加到converts中 app.url_map.converters['regex'] = RegexConverter # 进行使用 @app.route('/index/<regex("\d+"):nid>',endpoint='xx') def index(nid): url_for('xx',nid=123) #反向生成,就会去执行to_url方法 return "Index" if __name__ == '__main__': app.run()
二、视图函数
1、diango中的CBV模式
2、Flask中的CBV模式
def auth(func): def inner(*args, **kwargs): result = func(*args, **kwargs) return result return inner class IndexView(views.MethodView): # methods = ['POST'] #只允许POST请求访问 decorators = [auth,] #如果想给所有的get,post请求加装饰器,就可以这样来写,也可以单个指定 def get(self): #如果是get请求需要执行的代码 v = url_for('index') print(v) return "GET" def post(self): #如果是post请求执行的代码 return "POST"
app.add_url_rule('/index', view_func=IndexView.as_view(name='index')) #name指定的是别名,会当做endpoint使用 if __name__ == '__main__': app.run()
3、Flask中的FBV模式
两种方式:
方式一: @app.route('/index',endpoint='xx') def index(nid): url_for('xx',nid=123) return "Index" 方式二: def index(nid): url_for('xx',nid=123) return "Index" app.add_url_rule('/index',index)
三、请求与响应
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1 from flask import Flask 2 from flask import request 3 from flask import render_template 4 from flask import redirect 5 from flask import make_response 6 7 app = Flask(__name__) 8 9 10 @app.route('/login.html', methods=['GET', "POST"]) 11 def login(): 12 13 # 请求相关信息 14 # request.method 15 # request.args 16 # request.form 17 # request.values 18 # request.cookies 19 # request.headers 20 # request.path 21 # request.full_path 22 # request.script_root 23 # request.url 24 # request.base_url 25 # request.url_root 26 # request.host_url 27 # request.host 28 # request.files 29 # obj = request.files['the_file_name'] 30 # obj.save('/var/www/uploads/' + secure_filename(f.filename)) 31 32 # 响应相关信息 33 # return "字符串" 34 # return render_template('html模板路径',**{}) 35 # return redirect('/index.html') 36 37 # response = make_response(render_template('index.html')) 38 # response是flask.wrappers.Response类型 39 # response.delete_cookie('key') 40 # response.set_cookie('key', 'value') 41 # response.headers['X-Something'] = 'A value' 42 # return response 43 44 45 return "内容" 46 47 if __name__ == '__main__': 48 app.run()
from flask import Flask,url_for,request,redirect,render_template,jsonify,make_response from urllib.parse import urlencode,quote,unquote app = Flask(__name__) @app.route('/index',endpoint='xx') def index(): from werkzeug.datastructures import ImmutableMultiDict
================= # get_data = request.args # get_dict = get_data.to_dict() # get_dict['xx'] = '18' # url = urlencode(get_dict) # print(url) ==================== # print(request.query_string) # print(request.args) ========================== # val = "%E6%8A%8A%E5%87%A0%E4%B8%AA" # print(unquote(val)) #吧上面这样的数据转换成中文 # # return "Index" # return "Index" # return redirect() # return render_template() # return jsonify(name='alex',age='18') #相当于JsonResponse ======================= response = make_response('xxxxx') ##如果是返回更多的值,cookie,headers,或者其他的就可用它 response.headers['xxx'] = '123123' return response if __name__ == '__main__': # app.__call__ app.run()
四、模板语法
1、为了防止xss攻击,加了验证,所以页面上显示字符串的形式,解决办法,有两种方式
- 在后端Markup
v5 = Markup("<input type='text' />")
- 在前端
{{ v4|safe }}
2、自定义方法
def test(a,b): return a+b @app.route('/index') def index(): return render_template("index2.html",test=test) index2.html <h1>{{ test(1,2) }}</h1>
3、写一个函数在所有的页面都使用
template_global和template_filter
@app.template_global() def sb(a1, a2): return a1 + a2 @app.template_filter() def db(a1, a2, a3): return a1 + a2 + a3
调用方式:{{sb(1,2)}} {{ 1|db(2,3)}}
4、模板继承:和django的一样。extents
5、宏:只有定义的东西在很多地方去使用的时候才去用它
{% macro input(name, type='text', value='') %} <input type="{{ type }}" name="{{ name }}" value="{{ value }}"> {% endmacro %} {{ input('n1') }}
练习:
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1 from flask import Flask,url_for,render_template,Markup 2 app = Flask(__name__) 3 4 def test(a,b): 5 return a+b 6 7 @app.template_global() 8 def sb(a1, a2): 9 return a1 + a2 + 100 10 11 12 @app.template_filter() 13 def db(a1, a2, a3): 14 return a1 + a2 + a3 15 16 @app.route('/index') 17 def index(): 18 v1 = "字符串" 19 v2 = [11,22,33] 20 v3 = {"k1":"v3","sdf":"sdgfgf"} 21 v4 = "<input type='text' />" 22 v5 = Markup("<input type='text' />") 23 return render_template("index2.html",v1=v1,v2=v2,v3=v3,v4=v4,v5=v5,test=test) 24 25 if __name__ == '__main__': 26 app.run(debug=True)
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1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <meta http-equiv="X-UA-Compatible" content="IE=edge"> 6 <meta name="viewport" content="width=device-width"> 7 <title>Title</title> 8 </head> 9 <body> 10 {{ v1 }} 11 <ul> 12 {% for foo in v2 %} 13 <li>{{ foo }}</li> 14 {% endfor %} 15 {{ v2.1 }} 16 17 {% for k,v in v3.items() %} 18 <li>{{ k }} {{ v }}</li> 19 {% endfor %} 20 {{ v3.k1 }} 21 {{ v3.get("k1") }} 22 23 {{ v4|safe }} 24 {{ v5 }} 25 26 <h1>{{ test(1,2) }}</h1> 27 <p>{{ sb(1,2) }}</p> 28 <p>{{ 1| db(2,3) }}</p> 29 </ul> 30 </body> 31 </html>
五、session
除请求对象之外,还有一个 session 对象。它允许你在不同请求间存储特定用户的信息。它是在 Cookies 的基础上实现的,并且对 Cookies 进行密钥签名要使用会话,你需要设置一个密钥。
-
设置:session['username'] = 'xxx'
- 删除:session.pop('username', None)
from flask import Flask,url_for,session app = Flask(__name__) app.secret_key = "sdsfdgdgdgd" app.config['SESSION_COOKIE_NAME'] = 'session_lvning' #设置session的名字 @app.route('/index/') def index(nid): #session本质上操作的是字典, session是否还有其他方法?与字典方法相同 #session的原理:如果下一次访问的时候带着随机字符串,会把session里面对应的 # 值拿到内存,假设session保存在数据库,每执行一次链接一次数据库,每次都要时时更新的话 # 会非常损耗内存 session["xxx"] = 123 session["xxx2"] = 123 session["xxx3"] = 123 session["xxx4"] = 123 del session["xxx2"] #在这删除了,真正存储的时候是没有xxx2的 return "ddsf" if __name__ == '__main__': app.run()
关于session的配置
app.config['SESSION_COOKIE_NAME'] = 'session_lvning'
- session超时时间如何设置? 'PERMANENT_SESSION_LIFETIME': timedelta(days=31)
以下是跟session相关的配置文件
""" 'SESSION_COOKIE_NAME': 'session', 'SESSION_COOKIE_DOMAIN': None, 'SESSION_COOKIE_PATH': None, 'SESSION_COOKIE_HTTPONLY': True, 'SESSION_COOKIE_SECURE': False, 'SESSION_REFRESH_EACH_REQUEST': True, #是否每次都跟新 'PERMANENT_SESSION_LIFETIME': timedelta(days=31)
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1 from flask import Flask, session, redirect, url_for, escape, request 2 3 app = Flask(__name__) 4 5 @app.route('/') 6 def index(): 7 if 'username' in session: 8 return 'Logged in as %s' % escape(session['username']) 9 return 'You are not logged in' 10 11 @app.route('/login', methods=['GET', 'POST']) 12 def login(): 13 if request.method == 'POST': 14 session['username'] = request.form['username'] 15 return redirect(url_for('index')) 16 return ''' 17 <form action="" method="post"> 18 <p><input type=text name=username> 19 <p><input type=submit value=Login> 20 </form> 21 ''' 22 23 @app.route('/logout') 24 def logout(): 25 # remove the username from the session if it's there 26 session.pop('username', None) 27 return redirect(url_for('index')) 28 29 # set the secret key. keep this really secret: 30 app.secret_key = 'A0Zr98j/3yX R~XHH!jmN]LWX/,?RT'
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1 pip3 install Flask-Session 2 3 run.py 4 from flask import Flask 5 from flask import session 6 from pro_flask.utils.session import MySessionInterface 7 app = Flask(__name__) 8 9 app.secret_key = 'A0Zr98j/3yX R~XHH!jmN]LWX/,?RT' 10 app.session_interface = MySessionInterface() 11 12 @app.route('/login.html', methods=['GET', "POST"]) 13 def login(): 14 print(session) 15 session['user1'] = 'alex' 16 session['user2'] = 'alex' 17 del session['user2'] 18 19 return "内容" 20 21 if __name__ == '__main__': 22 app.run() 23 24 session.py 25 #!/usr/bin/env python 26 # -*- coding:utf-8 -*- 27 import uuid 28 import json 29 from flask.sessions import SessionInterface 30 from flask.sessions import SessionMixin 31 from itsdangerous import Signer, BadSignature, want_bytes 32 33 34 class MySession(dict, SessionMixin): 35 def __init__(self, initial=None, sid=None): 36 self.sid = sid 37 self.initial = initial 38 super(MySession, self).__init__(initial or ()) 39 40 41 def __setitem__(self, key, value): 42 super(MySession, self).__setitem__(key, value) 43 44 def __getitem__(self, item): 45 return super(MySession, self).__getitem__(item) 46 47 def __delitem__(self, key): 48 super(MySession, self).__delitem__(key) 49 50 51 52 class MySessionInterface(SessionInterface): 53 session_class = MySession 54 container = {} 55 56 def __init__(self): 57 import redis 58 self.redis = redis.Redis() 59 60 def _generate_sid(self): 61 return str(uuid.uuid4()) 62 63 def _get_signer(self, app): 64 if not app.secret_key: 65 return None 66 return Signer(app.secret_key, salt='flask-session', 67 key_derivation='hmac') 68 69 def open_session(self, app, request): 70 """ 71 程序刚启动时执行,需要返回一个session对象 72 """ 73 sid = request.cookies.get(app.session_cookie_name) 74 if not sid: 75 sid = self._generate_sid() 76 return self.session_class(sid=sid) 77 78 signer = self._get_signer(app) 79 try: 80 sid_as_bytes = signer.unsign(sid) 81 sid = sid_as_bytes.decode() 82 except BadSignature: 83 sid = self._generate_sid() 84 return self.session_class(sid=sid) 85 86 # session保存在redis中 87 # val = self.redis.get(sid) 88 # session保存在内存中 89 val = self.container.get(sid) 90 91 if val is not None: 92 try: 93 data = json.loads(val) 94 return self.session_class(data, sid=sid) 95 except: 96 return self.session_class(sid=sid) 97 return self.session_class(sid=sid) 98 99 def save_session(self, app, session, response): 100 """ 101 程序结束前执行,可以保存session中所有的值 102 如: 103 保存到resit 104 写入到用户cookie 105 """ 106 domain = self.get_cookie_domain(app) 107 path = self.get_cookie_path(app) 108 httponly = self.get_cookie_httponly(app) 109 secure = self.get_cookie_secure(app) 110 expires = self.get_expiration_time(app, session) 111 112 val = json.dumps(dict(session)) 113 114 # session保存在redis中 115 # self.redis.setex(name=session.sid, value=val, time=app.permanent_session_lifetime) 116 # session保存在内存中 117 self.container.setdefault(session.sid, val) 118 119 session_id = self._get_signer(app).sign(want_bytes(session.sid)) 120 121 response.set_cookie(app.session_cookie_name, session_id, 122 expires=expires, httponly=httponly, 123 domain=domain, path=path, secure=secure)
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1 #!/usr/bin/env python 2 # -*- coding:utf-8 -*- 3 """ 4 pip3 install redis 5 pip3 install flask-session 6 7 """ 8 9 10 from flask import Flask, session, redirect 11 from flask.ext.session import Session 12 13 14 app = Flask(__name__) 15 app.debug = True 16 app.secret_key = 'asdfasdfasd' 17 18 19 app.config['SESSION_TYPE'] = 'redis' 20 from redis import Redis 21 app.config['SESSION_REDIS'] = Redis(host='192.168.0.94',port='6379') 22 Session(app) 23 24 25 @app.route('/login') 26 def login(): 27 session['username'] = 'alex' 28 return redirect('/index') 29 30 31 @app.route('/index') 32 def index(): 33 name = session['username'] 34 return name 35 36 37 if __name__ == '__main__': 38 app.run()
六、blueprint,蓝图
七、闪现 : flash
session存在在服务端的一个字典里面,session保存起来,取一次里面还是有的,直到你删除之后才没有了
1、本质:flash是基于session创建的,flash支持往里边放值,只要你取一下就没有了,相当于pop了一下。不仅吧值取走,而且吧session里的东西去掉
2、闪现有什么用?
from flask import Flask,session,Session,flash,get_flashed_messages,redirect,render_template,request app = Flask(__name__) app.secret_key ='sdfsdfsdf' @app.route('/users') def users(): # 方式一 # msg = request.args.get('msg','') # 方式二 # msg = session.get('msg') # if msg: # del session['msg'] # 方式三 v = get_flashed_messages() print(v) msg = '' return render_template('users.html',msg=msg) @app.route('/useradd') def user_add(): # 在数据库中添加一条数据 # 假设添加成功,在跳转到列表页面时,显示添加成功 # 方式一 # return redirect('/users?msg=添加成功') # 方式二 # session['msg'] = '添加成功' # 方式三 flash('添加成功') return redirect('/users') if __name__ == '__main__': app.run(debug=True)
八、扩展
1、在函数执行之前或函数执行之后做点事情
第一种:装饰器
第二种:flask里面的扩展,相当于django中的中间件
from flask import Flask,session,Session,flash,get_flashed_messages,redirect,render_template,request app = Flask(__name__) app.secret_key ='sdfsdfsdf' @app.before_request def process_request1(): print('process_request1') @app.after_request def process_response1(response): print('process_response1') return response @app.before_request def process_request2(): print('process_request2') @app.after_request def process_response2(response): #参数也得有 print('process_response2') return response #必须有返回值 @app.route('/index') def index(): print('index') return 'Index' @app.route('/order') def order(): print('order') return 'order' @app.route('/test') def test(): print('test') return 'test' if __name__ == '__main__': app.run()
运行结果:
还有一个@app.before_first_request:表示,当程序运行起来,第一个请求来的时候就只执行一次,下次再来就不会在执行了