本文實例講述了Flask框架Flask-Principal基本用法。分享給大家供大家參考，具體如下：
Flask-Principal是Flask框架的一個擴展，主要主件是Identity，Needs，Permission和IdentityContext。
安裝
pip install flask-principal
初始化
from flask_principal import Principalprincipal = Principal()principal.init_app(app)
權限管理
permissions.py
from flask-principal import Permission,RoleNeedfrom functools import wraps# 定義相關角色NORMAL = "NORMAL"ADMIN = "ADMIN"ROLES = ( ("NORMAL","普通用戶"), ("ADMIN","管理員"))admin_permission = Permission(RoleNeed(ADMIN))def admin_authority(func): @wraps def decorated_view(*args,**kwargs): if admin_permission.can(): return func(*args,**kwargs) else: return "非Admin用戶" return decorated_view添加Role Model
userinfo.py
from app import login_managerfrom app.db import Base,engine,sessionfrom sqlalchemy import Column,String,Integer,create_enginefrom sqlalchemy_utils.types.choice import ChoiceTypefrom flask_login import UserMixinfrom permissions import ADMIN,ROLESclass User(Base,UserMixin): __tablename__ = "user" id = Column(Integer,primary_key=True) user = Column(String(16)) password = Column(String(16)) roles = Column(ChoiceType(ROLES),default=ADMIN)@login_manager.user_loadeddef user_loaded(id): return session.query(User).filter_by(id=id).first()Base.metadata.create_all(engine)
使用user_loader裝飾器的回調函數非常重要，它將決定user對象是否在登錄狀態。試想只有Admin權限操作的事情，那么此用戶是必需先登錄，否則無法驗證Admin權限。更多Flask-Login相關操作可參考《Flask框架Flask-Login用法》
登錄
驗證用戶與密碼等是否正確，后執行Flask-Login登錄操作，記錄登錄狀態，驗證用戶權限
from app import appfrom flask import requestfrom flask_login import login_userfrom flask_principal import current_app,identity_changed,Identityfrom userinfo import Userfrom app.db import session@app.route("/login",methods=["POST"])def login(): user = request.form.get("user",None) password = request.form.get("password",None) if not user or not password: ... user = session.query(User).filter_by(user=user,password=password).first() if not user: ... # 登錄 login_user(user) # 發送信號，載入用戶權限 identity_changed.send(current_app._get_current_object(),identity=Identity(user.id)) return ... identity_changed.send()函數會將sender:current_app._get_current_object()當前應用app和身份對象和identity:Identity(user.id)用戶對象以信號的新式發送出去，開發者可以用identity_loaded.connect_via(app)接收信號，并載入權限
from flask_login import current_userfrom flask_principal import identity_loaded,UserNeed,RoleNeed@identity_loaded.connect_via(app)def on_identity_loaded(sendder,identity): identity.user = current_user if hasattr(current_user,"id"): identity.provides.add(UserNeed(current_user.id)) if hasattr(current_user,"roles"): identity.provides.add(RoleNeed(current_user.roles.code))
實現只有Admin權限用戶才能操作刪除用戶
from app import appfrom permission import admin_authority@app.route("/delete_user",methods=["POST"])@admin_authoritydef delete_user(): ...希望本文所述對大家基于Flask框架的Python程序設計有所幫助。
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