使用Angularjs和nodejs的Mongodb CRUD操作-如果数据已经存在，如何从数据库中获取消息

Question

在controller.js:中

angular.module('CRUD').controller('myController',['$scope','$http', function($scope,$http){
    $scope.sendData = function(){
        console.log($scope.data1);
        var formData = {
        "username" :$scope.username,
        "email"    :$scope.email
    };
    $http({
        url:'/formData',
        method:'POST',
        data:formData
    }).success(function(data){
        console.log(data);
    });

}
}]).directive("myFirstDirective",function(){
    return
    {
        template:"<b>custom directive</b>",
        restrict:'E';
    }
});

Answer 1

1. 在您的nodeJS路由API中

//User Schema
'use strict';
var mongoose = require('mongoose');
var Schema = mongoose.Schema;
var UserSchema = new Schema({
  username: String,
  email: {
    type: String,
    unique: true //means the email has to be unique across all documents
  }
});
UserSchema.path('email').validate(function(value, done) {
    this.model('User').count({ email: value }, function(err, count) {
        if (err) {
            return done(err);
        } 
        // If `count` is greater than zero, "invalidate"
        done(!count);
    });
}, 'Email already exists');
module.exports = mongoose.model('User', UserSchema);
...
//API 
app.post('/formData', function(req, res){
    User.create(req.body, function(err){
        if (!err){
           res.send(200); //user created
        }
        else {
           if (err.name === 'ValidationError') res.send(409); //stands for form validation error
           else res.send(500);
        }
    });
});

2. 将您的请求提交到服务中的良好做法。例如

angular.module('CRUD').controller('myController',['$scope','$http', 'CRUDService', function($scope,$http, CRUDService){
    $scope.sendData = function(){
      CRUDService.createUser({
          username: $scope.username,
          email: $scope.email
      }).then(function(res){
         //all good user was created
      }, function(err){
         //error, failed to create user
         if (err.status === 409){
            //email already exists
         }
      });
    }
}]).service('CRUDService', ['$http', function($http){
  this.createUser = function(postData){
     return $http.post('/formData', postData);
  }
}]);