知识点： - 给你一个路径 “settings.Foo”，找到类并获取去其中的大写的静态字段。 settings.py class Foo: DEBUG = True TEST = True xx.py import importlib path = "settings.Foo" p,c = path.rsplit('.',maxsplit=1) m = importlib.import_module(p) cls = getattr(m,c) # 如何找到这个类？ for key in dir(cls): if key.isupper(): print(key,getattr(cls,key))
一、基本使用
from flask import Flask app = Flask(__name__) @app.route('/') def hello_world(): return 'Hello World!' if __name__ == '__main__': app.run()
二、配置文件
flask中的配置文件是一个flask.config.Config对象（继承字典）,默认配置为： { 'DEBUG': get_debug_flag(default=False), 是否开启Debug模式 'TESTING': False, 是否开启测试模式 'PROPAGATE_EXCEPTIONS': None, 'PRESERVE_CONTEXT_ON_EXCEPTION': None, 'SECRET_KEY': None, 'PERMANENT_SESSION_LIFETIME': timedelta(days=31), 'USE_X_SENDFILE': False, 'LOGGER_NAME': None, 'LOGGER_HANDLER_POLICY': 'always', 'SERVER_NAME': None, 'APPLICATION_ROOT': None, '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, 'MAX_CONTENT_LENGTH': None, 'SEND_FILE_MAX_AGE_DEFAULT': timedelta(hours=12), 'TRAP_BAD_REQUEST_ERRORS': False, 'TRAP_HTTP_EXCEPTIONS': False, 'EXPLAIN_TEMPLATE_LOADING': False, 'PREFERRED_URL_SCHEME': 'http', 'JSON_AS_ASCII': True, 'JSON_SORT_KEYS': True, 'JSONIFY_PRETTYPRINT_REGULAR': True, 'JSONIFY_MIMETYPE': 'application/json', 'TEMPLATES_AUTO_RELOAD': None, } 方式一： app.config['DEBUG'] = True PS： 由于Config对象本质上是字典，所以还可以使用app.config.update(...) 方式二： app.config.from_pyfile("python文件名称") 如： settings.py DEBUG = True app.config.from_pyfile("settings.py") app.config.from_envvar("环境变量名称") 环境变量的值为python文件名称名称，内部调用from_pyfile方法 app.config.from_json("json文件名称") JSON文件名称，必须是json格式，因为内部会执行json.loads app.config.from_mapping({'DEBUG':True}) 字典格式 app.config.from_object("python类或类的路径") app.config.from_object('pro_flask.settings.TestingConfig') settings.py class Config(object): DEBUG = False TESTING = False DATABASE_URI = 'sqlite://:memory:' class ProductionConfig(Config): DATABASE_URI = 'mysql://user@localhost/foo' class DevelopmentConfig(Config): DEBUG = True class TestingConfig(Config): TESTING = True PS: 从sys.path中已经存在路径开始写 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
三、路由系统
基于装饰器实现的路由系统。
技术点：- functools.wraps(func),保留原函数的元信息
参数：
rule, URL规则 view_func, 视图函数名称 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， redirect_to=None, 重定向到指定地址 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 subdomain=None, 子域名访问
基本使用：
- endpoint,反向生成URL，默认函数名 - url_for('endpoint') / url_for("index",nid=777) - 动态路由： @app.route('/index/<int:nid>',methods=['GET','POST']) def index(nid): print(nid) return "Index"
- @app.route('/user/<username>')
- @app.route('/post/<int:post_id>')
- @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以下对应关系来处理：
DEFAULT_CONVERTERS = { 'default': UnicodeConverter, 'string': UnicodeConverter, 'any': AnyConverter, 'path': PathConverter, 'int': IntegerConverter, 'float': FloatConverter, 'uuid': UUIDConverter, }
def auth(func): def inner(*args, **kwargs): print('before') result = func(*args, **kwargs) print('after') return result return inner @app.route('/index.html',methods=['GET','POST'],endpoint='index') @auth def index(): return 'Index' 或 def index(): return "Index" self.add_url_rule(rule='/index.html', endpoint="index", view_func=index, methods=["GET","POST"]) or app.add_url_rule(rule='/index.html', endpoint="index", view_func=index, methods=["GET","POST"]) app.view_functions['index'] = index 或 def auth(func): def inner(*args, **kwargs): print('before') result = func(*args, **kwargs) print('after') return result return inner class IndexView(views.View): methods = ['GET'] decorators = [auth, ] def dispatch_request(self): print('Index') return 'Index!' app.add_url_rule('/index', view_func=IndexView.as_view(name='index')) # name=endpoint 或 class IndexView(views.MethodView): methods = ['GET'] decorators = [auth, ] def get(self): return 'Index.GET' def post(self): return 'Index.POST' app.add_url_rule('/index', view_func=IndexView.as_view(name='index')) # name=endpoint @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'] = 'wupeiqi.com:5000' @app.route("/", subdomain="admin") def static_index(): """Flask supports static subdomains This is available at static.your-domain.tld""" return "static.your-domain.tld" @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()
from flask import Flask,url_for app = Flask(__name__) # 步骤一：定制类 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 # 步骤二：添加到转换器 app.url_map.converters['reg'] = RegexConverter """ 1. 用户发送请求 2. flask内部进行正则匹配 3. 调用to_python(正则匹配的结果)方法 4. to_python方法的返回值会交给视图函数的参数 """ # 步骤三：使用自定义正则 @app.route('/index/<reg("d+"):nid>') def index(nid): print(nid,type(nid)) print(url_for('index',nid=987)) return "index" if __name__ == '__main__': app.run()
四、请求和响应
from flask import Flask,jsonify from flask import request from flask import render_template from flask import redirect from flask import make_response app = Flask(__name__) @app.route('/login.html', methods=['GET', "POST"]) def login(): # 请求相关信息 # request.method # request.args # request.form # request.values # request.cookies # request.headers # request.path # request.full_path # request.script_root # request.url # request.base_url # request.url_root # request.host_url # request.host # request.files # obj = request.files['the_file_name'] # obj.save('/var/www/uploads/' + secure_filename(f.filename)) # 响应相关信息 # return "字符串" #return jsonify({'k1': 'v1'}) # return render_template('html模板路径',**{}) # return redirect('/index.html') # response = make_response(render_template('index.html')) # response是flask.wrappers.Response类型 # response.delete_cookie('key') # response.set_cookie('key', 'value') # response.headers['X-Something'] = 'A value' # return response return "内容" if __name__ == '__main__': app.run()
五、模板
1、模板的使用
Flask使用的是Jinja2模板，所以其语法和Django无差别
- 基本数据类型：可以执行python语法，如：dict.get() list['xx']
- 传入函数
- django，自动执行
- flask，不自动执行
# 全局定义函数 @app.template_global() def sb(a1, a2): # {{sb(1,9)}} return a1 + a2 @app.template_filter() def db(a1, a2, a3): # {{ 1|db(2,3) }} return a1 + a2 + a3 # 模板继承 #layout.html <!DOCTYPE html> <html lang="zh-CN"> <head> <meta charset="UTF-8"> <title>Title</title> <meta name="viewport" content="width=device-width, initial-scale=1"> </head> <body> <h1>模板</h1> {% block content %}{% endblock %} </body> </html> #tpl.html {% extends "layout.html"%} {% block content %} {{users.0}} {% endblock %} # include {% include "form.html" %} #form.html <form> asdfasdf </form> # 宏 {% macro ccccc(name, type='text', value='') %} #默认不显示 <h1>宏</h1> <input type="{{ type }}" name="{{ name }}" value="{{ value }}"> <input type="submit" value="提交"> {% endmacro %} {{ ccccc('n1') }} #通过调用才会显示上面定义的函数 {{ ccccc('n2') }} # 安全 # 前端： {{u|safe}} # 前端： MarkUp("asdf")
注意：Markup等价django的mark_safe
六、session
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)
当请求刚到来：flask读取cookie中session对应的值：eyJrMiI6NDU2LCJ1c2VyIjoib2xkYm95，将该值解密并反序列化成字典，放入内存以便视图函数使用。
视图函数：
@app.route('/ses') def ses(): session['k1'] = 123 session['k2'] = 456 del session['k1'] return "Session"
当请求结束时，flask会读取内存中字典的值，进行序列化+加密，写入到用户cookie中。
from flask import Flask, session, redirect, url_for, escape, request app = Flask(__name__) @app.route('/') def index(): if 'username' in session: return 'Logged in as %s' % escape(session['username']) return 'You are not logged in' @app.route('/login', methods=['GET', 'POST']) def login(): if request.method == 'POST': session['username'] = request.form['username'] return redirect(url_for('index')) return ''' <form action="" method="post"> <p><input type=text name=username> <p><input type=submit value=Login> </form> ''' @app.route('/logout') def logout(): # remove the username from the session if it's there session.pop('username', None) return redirect(url_for('index')) # set the secret key. keep this really secret: app.secret_key = 'A0Zr98j/3yX R~XHH!jmN]LWX/,?RT' 基本使用
pip3 install Flask-Session run.py from flask import Flask from flask import session from pro_flask.utils.session import MySessionInterface app = Flask(__name__) app.secret_key = 'A0Zr98j/3yX R~XHH!jmN]LWX/,?RT' app.session_interface = MySessionInterface() @app.route('/login.html', methods=['GET', "POST"]) def login(): print(session) session['user1'] = 'alex' session['user2'] = 'alex' del session['user2'] return "内容" if __name__ == '__main__': app.run() session.py #!/usr/bin/env python # -*- coding:utf-8 -*- import uuid import json from flask.sessions import SessionInterface from flask.sessions import SessionMixin from itsdangerous import Signer, BadSignature, want_bytes class MySession(dict, SessionMixin): def __init__(self, initial=None, sid=None): self.sid = sid self.initial = initial super(MySession, self).__init__(initial or ()) def __setitem__(self, key, value): super(MySession, self).__setitem__(key, value) def __getitem__(self, item): return super(MySession, self).__getitem__(item) def __delitem__(self, key): super(MySession, self).__delitem__(key) class MySessionInterface(SessionInterface): session_class = MySession container = {} def __init__(self): import redis self.redis = redis.Redis() def _generate_sid(self): return str(uuid.uuid4()) def _get_signer(self, app): if not app.secret_key: return None return Signer(app.secret_key, salt='flask-session', key_derivation='hmac') def open_session(self, app, request): """ 程序刚启动时执行，需要返回一个session对象 """ sid = request.cookies.get(app.session_cookie_name) if not sid: sid = self._generate_sid() return self.session_class(sid=sid) signer = self._get_signer(app) try: sid_as_bytes = signer.unsign(sid) sid = sid_as_bytes.decode() except BadSignature: sid = self._generate_sid() return self.session_class(sid=sid) # session保存在redis中 # val = self.redis.get(sid) # session保存在内存中 val = self.container.get(sid) if val is not None: try: data = json.loads(val) return self.session_class(data, sid=sid) except: return self.session_class(sid=sid) return self.session_class(sid=sid) def save_session(self, app, session, response): """ 程序结束前执行，可以保存session中所有的值 如： 保存到resit 写入到用户cookie """ domain = self.get_cookie_domain(app) path = self.get_cookie_path(app) httponly = self.get_cookie_httponly(app) secure = self.get_cookie_secure(app) expires = self.get_expiration_time(app, session) val = json.dumps(dict(session)) # session保存在redis中 # self.redis.setex(name=session.sid, value=val, time=app.permanent_session_lifetime) # session保存在内存中 self.container.setdefault(session.sid, val) session_id = self._get_signer(app).sign(want_bytes(session.sid)) response.set_cookie(app.session_cookie_name, session_id, expires=expires, httponly=httponly, domain=domain, path=path, secure=secure) 自定义Session
#!/usr/bin/env python # -*- coding:utf-8 -*- """ pip3 install redis pip3 install flask-session """ from flask import Flask, session, redirect from flask.ext.session import Session app = Flask(__name__) app.debug = True app.secret_key = 'asdfasdfasd' app.config['SESSION_TYPE'] = 'redis' from redis import Redis app.config['SESSION_REDIS'] = Redis(host='192.168.0.94',port='6379') Session(app) @app.route('/login') def login(): session['username'] = 'alex' return redirect('/index') @app.route('/index') def index(): name = session['username'] return name if __name__ == '__main__': app.run() 第三方session
七、flash（了解即可）
在session中存储一个数据，读取时通过pop将数据移除。
from flask import Flask,flash,get_flashed_messages @app.route('/page1') def page1(): flash('临时数据存储','error') flash('sdfsdf234234','error') flash('adasdfasdf','info') return "Session" @app.route('/page2') def page2(): print(get_flashed_messages(category_filter=['error'])) return "Session"
八、中间件（了解即可）
# call方法什么时候出发？ # 用户发起请求时，才执行。 # 任务：在执行call方法之前，做一个操作，call方法执行之后做一个操作。 class Middleware(object): def __init__(self,old): self.old = old def __call__(self, *args, **kwargs): ret = self.old(*args, **kwargs) return ret if __name__ == '__main__': app.wsgi_app = Middleware(app.wsgi_app) app.run()
九、特殊装饰器
1. before_request ：先定义的先执行
2. after_request：先定义的后执行
from flask import Flask app = Flask(__name__) @app.before_request def x1(): print('before:x1') return '滚' #x1有返回值时 x1 -> xx2 -> x2 #x1无返回值时 x1 -> xx1 -> index ->xx2 ->x2 @app.before_request def xx1(): print('before:xx1') @app.after_request def x2(response): print('after:x2') return response @app.after_request def xx2(response): print('after:xx2') return response @app.route('/index') def index(): print('index') return "Index" if __name__ == '__main__': app.run()
3.errorhandler：定制错误信息
@app.errorhandler(404) def not_found(arg): print(arg) return "没找到"
十、CBV
flask中用的比较多的是FBV
import functools from flask import Flask,views app = Flask(__name__) def wrapper(func): @functools.wraps(func) def inner(*args,**kwargs): return func(*args,**kwargs) return inner class UserView(views.MethodView): # methods = ['GET'] #可指定允许的请求方式，只允许GET请求 decorators = [wrapper,] #批量添加装饰器，在执行get和post视图时会先执行装饰器 def get(self,*args,**kwargs): # self.dispatch_request 请求进来先走dispatch_request，和django类似 return 'GET' def post(self,*args,**kwargs): return 'POST' app.add_url_rule('/user',None,UserView.as_view('uuuu')) #uuu代表endpoint参数 if __name__ == '__main__': app.run()
十一、上下文管理
requset
flask-session