import os
#Flask的基礎庫
from flask import Flask, abort, request, jsonify, g, url_for
#Flaks的數(shù)據(jù)庫操作的庫
from flask.ext.sqlalchemy import SQLAlchemy
#Flask登錄注冊的庫
from flask.ext.httpauth import HTTPBasicAuth
#加密解密密碼的庫
from passlib.apps import custom_app_context as pwd_context
#URL安全序列化工具
from itsdangerous import (TimedJSONWebSignatureSerializer
             as Serializer, BadSignature, SignatureExpired)

app = Flask(__name__)
# 設置密鑰
app.config['SECRET_KEY'] = 'the quick brown fox jumps over the lazy dog'
# 數(shù)據(jù)庫的配置
app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///db.sqlite'
app.config['SQLALCHEMY_COMMIT_ON_TEARDOWN'] = True

#數(shù)據(jù)庫初始化
db = SQLAlchemy(app)
# 驗證的初始化
auth = HTTPBasicAuth()

class User(db.Model):
  __tablename__ = 'users'
  id = db.Column(db.Integer, primary_key=True)
  username = db.Column(db.String(32), index=True)
  password_hash = db.Column(db.String(64))
  # 加密密碼
  def hash_password(self, password):
    self.password_hash = pwd_context.encrypt(password)
  # 驗證密碼
  def verify_password(self, password):
    return pwd_context.verify(password, self.password_hash)
  # 生成token，并設置過期時間
  def generate_auth_token(self, expiration=600):
    s = Serializer(app.config['SECRET_KEY'], expires_in=expiration)
    return s.dumps({'id': self.id})
  # 靜態(tài)的驗證token的方法
  @staticmethod
  def verify_auth_token(token):
    s = Serializer(app.config['SECRET_KEY'])
    try:
      data = s.loads(token)
    except SignatureExpired:
      return None  # token過期
    except BadSignature:
      return None  # token無效
    user = User.query.get(data['id'])
    return user

@app.route('/api/users', methods=['POST'])
def new_user():
  username = request.json.get('username')
  password = request.json.get('password')
  if username is None or password is None:
    abort(400)  # 用戶名或者密碼為空
  if User.query.filter_by(username=username).first() is not None:
    abort(400)  # 用戶已存在
  user = User(username=username)
  # 加密密碼
  user.hash_password(password)
  # 保存進數(shù)據(jù)庫
  db.session.add(user)
  db.session.commit()
  # 成功注冊后返回用戶名，Location后面接著的是跳轉(zhuǎn)的地址
  return (jsonify({'username': user.username}), 201,
      {'Location': url_for('get_user', id=user.id, _external=True)})

# 登錄后獲取token
@app.route('/api/token')
@auth.login_required
def get_auth_token():
  # 設置token過期時間
  token = g.user.generate_auth_token(600)
  return jsonify({'token': token.decode('ascii'), 'duration': 600})

# 可以通過token或者賬號密碼登錄
@app.route('/api/resource')
@auth.login_required
def get_resource():
  # 如果token有效的話就返回username
  return jsonify({'data': 'Hello, %s!' % g.user.username})

# 有@auth.login_required標志的都要調(diào)用這個方法,傳token或者傳賬號和密碼
@auth.verify_password
def verify_password(username_or_token, password):
  # 首先驗證token
  user = User.verify_auth_token(username_or_token)
  if not user:
    # 然后再驗證用戶名和密碼
    user = User.query.filter_by(username=username_or_token).first()
    if not user or not user.verify_password(password):
      return False
  g.user = user
  return True

if __name__ == '__main__':
  # 如果這個數(shù)據(jù)庫不存在就創(chuàng)建
  if not os.path.exists('db.sqlite'):
    db.create_all()
  app.run(debug=True)