GAE-Python-Registration

import os
import re
from string import letters

import webapp2
import jinja2
import hashlib

from google.appengine.ext import db

template_dir = os.path.join(os.path.dirname(__file__), 'templates')
jinja_env = jinja2.Environment(loader = jinja2.FileSystemLoader(template_dir),
							   autoescape = True)

#定义user_key的亲节点
def user_key(name = 'default'):
    return db.key.from_path('User', name)

#定义数据模型User
class User(db.Model):
    username = db.StringProperty(required = True)
    password = db.StringProperty(required = True)
    created = db.DateTimeProperty(auto_now_add = True)
    last_modified = db.DateTimeProperty(auto_now = True)

    def render(self):
        return render_str("user.html", user = self)

#按照username查找用户
def user_search(username):
    return db.GqlQuery("select * from User where username='%s'" % username)

#验证cookie中的信息是否有效
def hash_str(s):
	return hashlib.md5(s).hexdigest()

def make_secure_val(s):
	return "%s|%s" % (s, hash_str(s))

def check_secure_val(h):
	val = h.split('|')[0]
	if h == make_secure_val(val):
		return val

def extract_cookie(s):
    return s.split('|')[0]

#使用正则表达式判断表单中的信息是否合法
USER_RE = re.compile(r"^[a-zA-Z0-9_-]{3,20}$")
def valid_username(username):
    return username and USER_RE.match(username)

PASSWORD_RE = re.compile(r"^.{3,20}$")
def valid_password(password):
    return password and PASSWORD_RE.match(password)

EMAIL_RE = re.compile(r"^[\S]+@[\S]+\.[\S]+$")
def valid_email(email):
    return not email or EMAIL_RE.match(email)

#渲染模板
def render_str(template, **params):
    t = jinja_env.get_template(template)
    return t.render(params)

#负责渲染模板的handler
class BaseHandler(webapp2.RequestHandler):
	def write(self, *a, **kw):
		self.response.out.write(*a, **kw)

	def render_str(self, template, **params):
		t = jinja_env.get_template(template)
		return t.render(params)

	def render(self, template, **kw):
		self.write(self.render_str(template, **kw))

#主handler
class MainHandler(BaseHandler):
    def get(self):
        self.render('main.html')

#注册或是登陆成功的handler
class WelcomeHandler(BaseHandler):
    def get(self):
        user_id = extract_cookie(self.request.cookies.get('user_id'))
        key = db.Key.from_path('User', int(user_id))
        user = db.get(key)
        if not user:
            self.error(404)
        else:
            self.render('welcome.html', username = user.username)

#处理注册的handler
class SignupHandler(BaseHandler):
    def get(self):
        self.render('registration.html')

    def post(self):
        have_error = False
        username = self.request.get('username')
        password = self.request.get('password')
        v_password = self.request.get('v_password')
        email = self.request.get('email')

        #验证表单合法性
        params = dict(username = username,
                      email = email)

        if not valid_username(username):
            params['username_error'] = "That's not a valid user name!"
            have_error = True

        if not valid_password(password):
            params['password_error'] = "That's not a valid password!"
            have_error = True
        elif password != v_password:
            params['verify_error'] = "Passwords didn't match!"
            have_error = True

        if not valid_email(email):
            params['email_error'] = "That's not a valid email!"
            have_error = True

        if not user_search(username):
            params['exist_error'] = "This user already exists!"
            have_error = True

        if have_error:
            self.render("registration.html", **params)
        else:
            u = User(username = username, password = password)
            u.put()
            self.response.headers.add_header('Set-Cookie', 'user_id=%s; Path=/' % str(u.key().id()))
            self.redirect('/welcome')

#打印所有用户信息的handler
class UserFront(BaseHandler):
    def get(self):
        users = db.GqlQuery("select * from User order by created desc limit 10")
        self.render('all-users.html', users = users)

#webapp2
app = webapp2.WSGIApplication([
    ('/', MainHandler),
    ('/signup', SignupHandler),
    ('/welcome', WelcomeHandler),
    ('/allusers', UserFront)
], debug=True)