Using Python to implement web user login and registration functions

_RE_MD5 = re.compile(r'^[0-9a-f]{32}$')

@api
@post('/api/users')
def register_user():
 i = ctx.request.input(name='', email='', password='')
 name = i.name.strip()
 email = i.email.strip().lower()
 password = i.password
 if not name:
  raise APIValueError('name')
 if not email or not _RE_EMAIL.match(email):
  raise APIValueError('email')
 if not password or not _RE_MD5.match(password):
  raise APIValueError('password')
 user = User.find_first('where email=?', email)
 if user:
  raise APIError('register:failed', 'email', 'Email is already in use.')
 user = User(name=name, email=email, password=password, image='http://www.gravatar.com/avatar/%s?d=mm&s=120' % hashlib.md5(email).hexdigest())
 user.insert()
 return user

{% extends '__base__.html' %}

{% block title %}注册{% endblock %}

{% block beforehead %}

<script>
function check_form() {
 $(&#39;#password&#39;).val(CryptoJS.MD5($(&#39;#password1&#39;).val()).toString());
 return true;
}
</script>

{% endblock %}

{% block content %}

<p class="uk-width-2-3">
 <h1>欢迎注册！</h1>
 <form id="form-register" class="uk-form uk-form-stacked" onsubmit="return check_form()">
  <p class="uk-alert uk-alert-danger uk-hidden"></p>
  <p class="uk-form-row">
   <label class="uk-form-label">名字:</label>
   <p class="uk-form-controls">
    <input name="name" type="text" class="uk-width-1-1">
   </p>
  </p>
  <p class="uk-form-row">
   <label class="uk-form-label">电子邮件:</label>
   <p class="uk-form-controls">
    <input name="email" type="text" class="uk-width-1-1">
   </p>
  </p>
  <p class="uk-form-row">
   <label class="uk-form-label">输入口令:</label>
   <p class="uk-form-controls">
    <input id="password1" type="password" class="uk-width-1-1">
    <input id="password" name="password" type="hidden">
   </p>
  </p>
  <p class="uk-form-row">
   <label class="uk-form-label">重复口令:</label>
   <p class="uk-form-controls">
    <input name="password2" type="password" maxlength="50" placeholder="重复口令" class="uk-width-1-1">
   </p>
  </p>
  <p class="uk-form-row">
   <button type="submit" class="uk-button uk-button-primary"><i class="uk-icon-user"></i> 注册</button>
  </p>
 </form>
</p>

{% endblock %}
Try

@api
@post('/api/authenticate')
def authenticate():
  i = ctx.request.input()
  email = i.email.strip().lower()
  password = i.password
  user = User.find_first('where email=?', email)
  if user is None:
    raise APIError('auth:failed', 'email', 'Invalid email.')
  elif user.password != password:
    raise APIError('auth:failed', 'password', 'Invalid password.')
  max_age = 604800
  cookie = make_signed_cookie(user.id, user.password, max_age)
  ctx.response.set_cookie(_COOKIE_NAME, cookie, max_age=max_age)
  user.password = '******'
  return user

# 计算加密cookie:
def make_signed_cookie(id, password, max_age):
  expires = str(int(time.time() + max_age))
  L = [id, expires, hashlib.md5('%s-%s-%s-%s' % (id, password, expires, _COOKIE_KEY)).hexdigest()]
  return '-'.join(L)

对于每个URL处理函数，如果我们都去写解析cookie的代码，那会导致代码重复很多次。

利用拦截器在处理URL之前，把cookie解析出来，并将登录用户绑定到ctx.request对象上，这样，后续的URL处理函数就可以直接拿到登录用户：

@interceptor('/')
def user_interceptor(next):
  user = None
  cookie = ctx.request.cookies.get(_COOKIE_NAME)
  if cookie:
    user = parse_signed_cookie(cookie)
  ctx.request.user = user
  return next()

# 解密cookie:
def parse_signed_cookie(cookie_str):
  try:
    L = cookie_str.split('-')
    if len(L) != 3:
      return None
    id, expires, md5 = L
    if int(expires) < time.time():
      return None
    user = User.get(id)
    if user is None:
      return None
    if md5 != hashlib.md5(&#39;%s-%s-%s-%s&#39; % (id, user.password, expires, _COOKIE_KEY)).hexdigest():
      return None
    return user
  except:
    return None
Try