登录用户 API 以允许访问特定用户的某些私有数据

/*****************************
login user
@required : username and password via post method only
@return user data if login successfull otherwise error message
****************************/
public function login(){
  $username=$this->input->post('username');
  $password=$this->input->post('password');
  if($username && $password){
    //check username and password
    if($this->login_credential['username']==$username && $this->login_credential['password']==$password){
      //set user data to store in session
      $userdata = array(
        'username'  => $this->login_credential['username'],
        'email'     => $this->login_credential['email'],
        'logged_in' => true
      );
      //set session
      $this->session->set_userdata($userdata);
      //display log in successfull msg
      $this->output->set_output(json_encode(array('status'=>true,'msg'=>'log in successfully','data'=>$userdata))); 
    }else{
      //wrong username or password
      $this->output->set_output(json_encode(array('status'=>false,'msg'=>'invalid Username or password'))); 
    }
  }else{
    //when username and password not set
    $this->output->set_output(json_encode(array('status'=>false,'msg'=>'provide Username and password')));
  }
}

https://i.stack.imgur.com/Xr7ZM.jpg