flask之基礎知識點

本篇導航:html

 

1、路由系統前端

一、可傳入參數:python

@app.route('/user/<username>')   #經常使用的   不加參數的時候默認是字符串形式的
@app.route('/post/<int:post_id>')  #經常使用的   #指定int,說明是整型的
@app.route('/post/<float:post_id>')
@app.route('/post/<path:path>')
@app.route('/login', methods=['GET', 'POST'])

經常使用路由系統有以上五種,全部的路由系統都是基於一下對應關係來處理:正則表達式

DEFAULT_CONVERTERS = { 'default': UnicodeConverter, 'string': UnicodeConverter, 'any': AnyConverter, 'path': PathConverter, 'int': IntegerConverter, 'float': FloatConverter, 'uuid': UUIDConverter, }
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二、反向生成URL: url_forredis

endpoint("name")   #別名,至關於django中的name數據庫

反向解析須要導入:django

from flask import Flask, url_for
@app.route('/index',endpoint="xxx")  #endpoint是別名
def index(): v = url_for("xxx") print(v) return "index" @app.route('/zzz/<int:nid>',endpoint="aaa")  #endpoint是別名
def zzz(nid): v = url_for("aaa",nid=nid) print(v) return "index2"
實例

三、@app.route和app.add_url_rule參數json

 @app.route和app.add_url_rule參數: rule, URL規則 view_func, 視圖函數名稱 defaults=None,              默認值,當URL中無參數,函數須要參數時,使用defaults={'k':'v'}爲函數提供參數 endpoint=None,              名稱,用於反向生成URL,即: url_for('名稱') methods=None,               容許的請求方式,如:["GET","POST"] strict_slashes=None,        對URL最後的 / 符號是否嚴格要求, 如: @app.route('/index',strict_slashes=False), 訪問 http://www.xx.com/index/ 或 http://www.xx.com/index都可 @app.route('/index',strict_slashes=True) 僅訪問 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, 子域名訪問 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"

                            #動態生成
                                                @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() 全部的域名都得與IP作一個域名解析:         若是你想經過域名去訪問,有兩種解決方式:           方式一:             1、租一個域名 haiyan.lalala             二、租一個公網IP  49.8.5.62
            3、域名解析: haiyan.com 49.8.5.62
            四、吧代碼放在49.8.5.62這個服務器上,程序運行起來               用戶能夠經過IP進行訪問           方式二:若是是本身測試用的就能夠用這種方式。先在本身本地的文件中找              C:\Windows\System32\drivers\etc 找到HOST,修改配置             而後吧域名修改爲本身的本地服務器127.0.0.1             加上配置:app.config["SERVER_NAME"] = "haiyan.com:5000"
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 四、練習flask

redirect_to:直接重定向,原url有參數時,跳轉是也得傳參,注意:不用加類型後端

#/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"
redirect_to
# ============對url最後的/符號是否嚴格要求=========
@app.route('/test',strict_slashes=True)  #當爲True時,url後面必須不加斜槓
def test(): return "aaaaaaaa" @app.route('/test',strict_slashes=False)  #當爲False時,url上加不加斜槓都行
def test(): return "aaaaaaaa"
strict_slashes
# =============== 子域名訪問============
@app.route("/static_index", subdomain="admin") def static_index(): return "admin.bjg.com"

# ===========動態生成子域名===========
@app.route("/index",subdomain='<xxxxx>') def index(xxxxx): return "%s.bjg.com" %(xxxxx,)
subdomain

擴展Flask的路由系統,讓他支持正則,這個類必須這樣寫,必須去繼承BaseConverter

from flask import Flask,url_for app = Flask(__name__) # 定義轉換的類
    from werkzeug.routing import BaseConverter class RegexConverter(BaseConverter): """ 自定義URL匹配正則表達式 """

        def __init__(self, map, regex): super(RegexConverter, self).__init__(map) self.regex = regex def to_python(self, value): """ 路由匹配時,匹配成功後傳遞給視圖函數中參數的值 :param value: :return: """
            return int(value) def to_url(self, value): """ 使用url_for反向生成URL時,傳遞的參數通過該方法處理,返回的值用於生成URL中的參數 :param value: :return: """ val = super(RegexConverter, self).to_url(value) return val # 添加到converts中
    app.url_map.converters['regex'] = RegexConverter # 進行使用
    @app.route('/index/<regex("\d+"):nid>',endpoint='xx') def index(nid): url_for('xx',nid=123)  #反向生成,就會去執行to_url方法
        return "Index"

    if __name__ == '__main__': app.run()
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2、視圖函數

一、diango中的CBV模式

 

二、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'] #只容許POST請求訪問
            decorators = [auth,]  #若是想給全部的get,post請求加裝飾器,就能夠這樣來寫,也能夠單個指定
  
            def get(self):   #若是是get請求須要執行的代碼
                v = url_for('index') print(v) return "GET"

            def post(self):  #若是是post請求執行的代碼
                return "POST" app.add_url_rule('/index', view_func=IndexView.as_view(name='index'))  #name指定的是別名,會當作endpoint使用

        if __name__ == '__main__': app.run()
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三、Flask中的FBV模式

兩種方式:

 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)
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3、請求與響應

from flask import Flask 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(): # 請求相關信息
        # 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))

        # 響應相關信息
        # return "字符串"
        # return render_template('html模板路徑',**{})
        # return redirect('/index.html')

        # response = make_response(render_template('index.html'))
        # response是flask.wrappers.Response類型
        # response.delete_cookie('key')
        # response.set_cookie('key', 'value')
        # response.headers['X-Something'] = 'A value'
        # return response


        return "內容"

    if __name__ == '__main__': app.run()
請求
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)) #吧上面這樣的數據轉換成中文
    #     # return "Index"

    # return "Index"
    # return redirect()
    # return render_template()
    # return jsonify(name='alex',age='18') #至關於JsonResponse
  ======================= response = make_response('xxxxx')   ##若是是返回更多的值,cookie,headers,或者其餘的就可用它
    response.headers['xxx'] = '123123'
    return response if __name__ == '__main__': # app.__call__
    app.run()
響應

 

4、模板語法

一、爲了防止xss攻擊,加了驗證,因此頁面上顯示字符串的形式,解決辦法,有兩種方式

  - 在後端Markup(須要導入)

v5 = Markup("<input type='text' />")

  - 在前端

{{ v4|safe }}

二、自定義方法

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>
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三、寫一個函數在全部的頁面都使用

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
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調用方式:{{sb(1,2)}} {{ 1|db(2,3)}}

四、模板繼承:和django的同樣。extents

五、宏:只有定義的東西在不少地方去使用的時候纔去用它

{% macro input(name, type='text', value='') %}
    <input type="{{ type }}" name="{{ name }}" value="{{ value }}">
{% endmacro %}

{{ input('n1') }}

 六、練習  

from flask import Flask,url_for,render_template,Markup app = Flask(__name__) def test(a,b): return a+b @app.template_global() def sb(a1, a2): return a1 + a2 + 100 @app.template_filter() def db(a1, a2, a3): return a1 + a2 + a3 @app.route('/index') def index(): v1 = "字符串" v2 = [11,22,33] v3 = {"k1":"v3","sdf":"sdgfgf"} v4 = "<input type='text' />" v5 = Markup("<input type='text' />") return render_template("index2.html",v1=v1,v2=v2,v3=v3,v4=v4,v5=v5,test=test) if __name__ == '__main__': app.run(debug=True)
模板語法
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width">
    <title>Title</title>
</head>
<body> {{ v1 }} <ul> {% for foo in v2 %} <li>{{ foo }}</li> {% endfor %} {{ v2.1 }} {% for k,v in v3.items() %} <li>{{ k }} {{ v }}</li> {% endfor %} {{ v3.k1 }} {{ v3.get("k1") }} {{ v4|safe }} {{ v5 }} <h1>{{ test(1,2) }}</h1>
    <p>{{ sb(1,2) }}</p>
    <p>{{ 1| db(2,3) }}</p>
</ul>
</body>
</html> index2.html
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5、session

除請求對象以外,還有一個 session 對象。它容許你在不一樣請求間存儲特定用戶的信息。它是在 Cookies 的基礎上實現的,而且對 Cookies 進行密鑰簽名要使用會話,你須要設置一個密鑰。

  • 設置:session['username'] = 'xxx'

  • 刪除: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'  #設置session的名字
 @app.route('/index/') def index(nid): #session本質上操做的是字典, session是否還有其餘方法?與字典方法相同
    #session的原理:若是下一次訪問的時候帶着隨機字符串,會把session裏面對應的
    # 值拿到內存,假設session保存在數據庫,每執行一次連接一次數據庫,每次都要時時更新的話
    # 會很是損耗內存
    session["xxx"] = 123 session["xxx2"] = 123 session["xxx3"] = 123 session["xxx4"] = 123
    del session["xxx2"]  #在這刪除了,真正存儲的時候是沒有xxx2的
    return "ddsf"

if __name__ == '__main__': app.run()
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關於session的配置

app.config['SESSION_COOKIE_NAME'] = 'session_lvning'

- session超時時間如何設置?      'PERMANENT_SESSION_LIFETIME':           timedelta(days=31) 如下是跟session相關的配置文件 """ '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)
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 "內容"

            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): """ 程序剛啓動時執行,須要返回一個session對象 """ 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保存在內存中
                    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): """ 程序結束前執行,能夠保存session中全部的值 如: 保存到resit 寫入到用戶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保存在內存中
 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)
自定義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

 

6、藍圖(blueprint)、閃現 (flash) 

一、藍圖用於爲應用提供目錄劃分(例:創建如圖目錄結構)

二、各py文件示例

from pro_flask import app if __name__ == '__main__': app.run()
run.py
from flask import Blueprint from flask import render_template from flask import request account = Blueprint('account', __name__) @account.route('/login.html', methods=['GET', "POST"]) def login(): return render_template('login.html')
account.py
from flask import Flask app = Flask(__name__,template_folder='templates',static_folder='statics',static_url_path='/static') from .views.account import account from .views.blog import blog from .views.user import user app.register_blueprint(account) app.register_blueprint(blog) app.register_blueprint(user)
__init__.py

三、注意點

四、大型項目藍圖使用

五、session存在在服務端的一個字典裏面,session保存起來,取一次裏面仍是有的,直到你刪除以後纔沒有了

1)本質:flash是基於session建立的,flash支持往裏邊放值,只要你取一下就沒有了,至關於pop了一下。不只吧值取走,並且吧session裏的東西去掉

2)閃現有什麼用?

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(): # 在數據庫中添加一條數據
    # 假設添加成功,在跳轉到列表頁面時,顯示添加成功
    # 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)
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 7、擴展

一、在函數執行以前或函數執行以後作點事情

第一種:裝飾器

第二種:flask裏面的擴展,至關於django中的中間件

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):   #參數也得有
    print('process_response2') return response   #必須有返回值
 @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()
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運行結果:

還有一個@app.before_first_request:表示,當程序運行起來,第一個請求來的時候就只執行一次,下次再來就不會在執行了

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