验证电子邮件和用户名，在清新的风格

Question

我需要保存到数据库之前验证用户名（如果提供了一个）和电子邮件（如果提供了一个）。我使用MongooseJS，但是，我不知道如何组织我的代码

这是我到目前为止有：

var user = new User(); 
if(req.body.email) { 
    User.findOne({"email" : req.body.email}, function(err, found){ 
     if(err) return next(err); 
     if(found) return res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Email address already exists"}); 
    }); 
} 

if(req.body.username) { 
    User.findOne({"username" : req.body.username}, function(err, found){ 
     if(err) return next(err); 
     if(found) return res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Username already exists"}); 
    }); 
} 

user.save(function(err){ 
    if(err) return next(err); 
    res.status(200).send(user); 
}); 

但当然，这将无法工作作为user.save会在任一验证块执行之前执行。我知道我可以把user.save回调中，但随后我会重复，我想避免的代码。

Answer 1

另一种简单的方法也许

var user = new User(); 
var email = req.body.email || ''; 
var username = req.body.username || ''; 

User.find({ 
      $or: [{"email": email}, {"username": username}]}, 
      function(err, users){ 
      if(err) return next(err); 
      if(users && users.length == 0) { 
       // save new user if none is matched 
       user.save(function(err){ 
         if(err) return next(err); 
         res.status(200).send(user); 
       }); 
      } else if (users && users.length > 0) { 
       // check users returned to determine which of following two error codes should be returned 
       //return res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Email address already exists"}); 
       //return res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Username already exists"}); 
      } 
}); 

---

你可以做到这一点通过Promise，这里是一个示例代码使用Q.js

function findUserByEmail() { 
    var deferred = Q.defer(); 
    if(req.body.email) { 
     User.findOne({"email" : req.body.email}, function(err, found){ 
      if(err) return deferred.reject(err); 
      if(found) { 
       res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Email address already exists"}); 
       deferred.reject(); 
      }else { 
       // no user is found, resolve it 
       deferred.resolve(); 
      } 
     }); 
    } else { 
     deferred.reject(); 
    } 
    return deferred.promise; 
} 

function findUserByName() { 
    var deferred = Q.defer(); 
    if(req.body.username) { 
     User.findOne({"username" : req.body.username}, function(err, found){ 
      if(err) return deferred.reject(err); 
      if(found) { 
       res.status(200).send({"error_code" : "INVALID_REQUEST_ERROR", "message" : "Username already exists"}); 
       deferred.reject(); 
      } else { 
       // no user is found, resolve it 
       deferred.resolve(); 
      } 
     }); 
    } else { 
     deferred.reject(); 
    } 
    return deferred.promise; 
} 

Q.all([findUserByName(), findUserByEmail()]).then (function() { 
    // in the resolve function, namely, no exist username and email 
    user.save(function(err){ 
     if(err) return next(err); 
     res.status(200).send(user); 
    }); 
}); 

Answer 2

的最好的办法是增加validation on to your mongoose Schema和让它在您尝试保存模型时自动执行（或者您可以先前调用验证函数）。像这样：

var userSchema = new Schema({ 
    email: { 
     type: String, 
     required: true, 
     validate: { 
      validator: function(v) { 
       var emailRegexp = /^[-a-z0-9~!$%^&*_=+}{\'?]+(\.[-a-z0-9~!$%^&*_=+}{\'?]+)*@([a-z0-9_][-a-z0-9_]*(\.[-a-z0-9_]+)*\.(aero|arpa|biz|com|coop|edu|gov|info|int|mil|museum|name|net|org|pro|travel|mobi|[a-z][a-z])|([0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}))(:[0-9]{1,5})?$/i; 

       return emailRegexp.test(v); 
      }, 
      message: "{VALUE} does not appear to be a valid email address." 
     } 
    } 
}); 

然后，当你尝试将其与不正确的数据保存：

var user = new User({ email: "this_isnt_a_proper_email" }); 

user.save(function(err) { 
    if (err.name === "ValidationError") { // check that it comes from mongoose validation 
     console.log(err.errors.email.message) 
     res.status(400).send({ validationError: err }); // send "Bad Request" HTTP header 
    } else { 
     res.send(user) // status 200 is implicit when not set 
    } 
}); 

为了更好地组织，检查是否有用户名或电子邮件数据库中已经设置了密码，我建议查找Bluebird（或类似的）Promises，这样你就可以拥有一个逻辑流程。