错误状态:使用angular js和codeigniter 2.2

我刚刚开始学习angular js.我正在使用codeigniter 2.2。我有一个页面显示所有的用户在表中使用angular js。在同一页面上，我有添加用户表单。我想通过表单保存数据，使用angular js。打印机错误:500(红色)*数据不保存。为什么会发生这种情况，如何解决。请按我说的做。谢谢。

下面是我的代码结构。

demo_angular.js

var angularapp = angular.module('angularapp', []); 
// add user
angularapp.controller ('FrmController',function ($scope , $http) {
    $scope.errors = [];
    $scope.msgs = [];
    $scope.addUser = function() {
        $scope.errors.splice(0, $scope.errors.length); // remove all error messages
        $scope.msgs.splice(0, $scope.msgs.length);
        $http.post("../admin/users/add_user", {'fname': $scope.fname, 'lname': $scope.lname, 'uname': $scope.uname,'gender': $scope.gender,'email': $scope.email,'mobile': $scope.mobile,'pass': $scope.pass}
        ).success(function(data, status, headers, config) {
            if (data.msg != '')
            {
                $scope.msgs.push(data.msg);
                $scope.get_users();
            }
            else
            {
                $scope.errors.push(data.error);
            }
        }).error(function(data, status) { // called asynchronously if an error occurs
// or server returns response with an error status.
            $scope.errors.push(status);
        });
    }
});

视图:

<form name="form_add" method="post" ng-controller="FrmController">
                     <ul>
                        <li style="color:red" ng-repeat="error in errors"> {{ error}} </li>
                    </ul>
                    <ul>
                        <li style="color:green" ng-repeat="msg in msgs"> {{ msg}} </li>
                    </ul>
                        <table class="table" cellspacing=10 cellpadding=10>
                        <tr>
                        <td>First Name: <input required type="text" ng-pattern="/[a-zA-Z]$/"  ng-model="fname"  name="fname" id="fname" value=""/><br/>
                        <span style="color:red" ng-show="form_add.fname.$dirty && form_add.fname.$invalid">
                                <span ng-show="form_add.fname.$error.required">First Name is required.</span>
                                <span ng-show="form_add.fname.$error.pattern">Invalid</span>
                        </span>
                        </td>
                        <td>Last Name: <input required type="text" ng-pattern="/[a-zA-Z]$/" ng-model="lname" name="lname" id="lname" value=""/><br/>
                        <span style="color:red" ng-show="form_add.lname.$dirty && form_add.lname.$invalid">
                                <span ng-show="form_add.lname.$error.required">Last Name is required.</span>
                                <span ng-show="form_add.lname.$error.pattern">Invalid</span>
                        </span>
                        </td>
                        <td>User Name: <input required type="text" ng-pattern="/^[a-zA-Z0-9]{6,15}$/"   ng-model="uname" name="uname" id="uname" value=""/><br/>
                        <span style="color:red" ng-show="form_add.uname.$dirty && form_add.uname.$invalid">
                                <span ng-show="form_add.uname.$error.required">User Name is required.</span>
                                <span ng-show="form_add.uname.$error.pattern">Invalid: Minimum 6 characters and maximum 15 characters</span>    
                        </span>
                        </td>
                        <td width="20%">Gender :<br/> <input type="radio"  ng-model="gender" name="gender" id="r1" value="m" checked/>Male
                        &nbsp;&nbsp;<input type="radio"  ng-model="gender" name="gender" id="r2" value="f"/>Female</td>
                        </tr>
                        <tr>
                        <td>Email ID: <input type="text" required ng-pattern="/^[a-z]+[a-z0-9._]+@[a-z]+'.[a-z.]{2,5}$/"  ng-model="email" name="email" id="email" value=""/><br/>
                            <span style="color:red" ng-show="form_add.email.$dirty && form_add.email.$invalid">
                                <span ng-show="form_add.email.$error.required">Email is required.</span>
                                <span ng-show="form_add.email.$error.pattern">Invalid email address.</span>
                            </span>
                        </td>
                        <td>Mobile : <input type="text" required  ng-model="mobile" ng-pattern="/^[1-9]{1}[0-9]{9}$/"  name="mobile" id="mobile" value=""/><br/>
                        <span style="color:red" ng-show="form_add.mobile.$dirty && form_add.mobile.$invalid">
                                <span ng-show="form_add.mobile.$error.required">Mobile is required.</span>
                                <span ng-show="form_add.mobile.$error.pattern">10 digits required</span>
                        </span>
                        </td>
                        <td>Password : <input required type="password" ng-model="pass" name="pass" id="pass" value=""/>
                        <span style="color:red" ng-show="form_add.mobile.$dirty && form_add.mobile.$invalid">
                                <span ng-show="form_add.mobile.$error.required">Mobile is required.</span>
                                <span ng-show="form_add.mobile.$error.pattern">10 digits required</span>
                        </span>
                        </td>
                        <td><button type="button" class="btn btn-primary" ng-click='addUser();'>Save</button></td>
                        </tr>
                        </table>
                    <br/>
                    </form>

Codeigniter控制器函数:

public function add_user()
    {
        $data = json_decode(file_get_contents("php://input"));
    //  print_r($data); exit;
        $my_data['fname']=$data->fname;
        $my_data['lname']=$data->lname;
        $my_data['uname']=$data->uname;
        $my_data['gender']=$data->gender;
        $my_data['email']=$data->email;
        $my_data['mobile']=$data->mobile;
        $my_data['pass']=$data->pass;
        $result=$this->vanesh_model->add_user($my_data);
         if ($result) 
         {
            $arr = array('msg' => "User Created Successfully!!!", 'error' => '');
            $jsn = json_encode($arr);
            print_r($jsn);
        }
        else
        {
            $arr = array('msg' => "", 'error' => 'Error In inserting record');
            $jsn = json_encode($arr);
            print_r($jsn);
        } 
    }

模型:

public function add_user($my_data)
    {
        $this->db->insert('user', $my_data); 
        return $this->db->insert_id();
    }

编辑://查看所有用户

angularapp.controller('angular_controller',function ($scope , $http) {
     $scope.orderByField = 'fname';
    $scope.get_users = function() {
        $http.get("../admin/users/angular_all_users").success(function(data)
        {
            $scope.allUsers = data;    
        });
}
});