ABP学习入门系列（四）（创建Service）

一，一些相关解释

Service 在应用服务层也就是application层。应用服务用于将领域(业务)逻辑暴露给展现层。展现层通过传入DTO(数据传输对象)参数来调用应用服务，而应用服务通过领域对象来执行相应的业务逻辑并且将DTO返回给展现层。

也就是这样避免了应用服务层和展现层的，直接数据交互，而是通过dto实现了数据过滤，这样就可以较好的避免非法数据的传入传出。另外大头还要实现数据隐藏，方便扩展等好处。

创建应用服务时需要注意：

1.service 要实现IApplicationService接口。

2，ABP为IApplicationService提供默认实现ApplicationService

3，ABP中，一个应用服务方法默认是一个工作单元（Unit of Work）。ABP针对UOW模式自动进行数据库的连接及事务管理，且会自动保存数据修改。

二，XXService和IXXService

1，如下TaskAppService 继承了LearningMpaAbpAppServiceBase，并实现了ITaskAppService接口

using Abp.Application.Services.Dto;
using Abp.Authorization;
using Abp.AutoMapper;
using Abp.Domain.Repositories;
using Abp.Events.Bus;
using Abp.Extensions;
using Abp.Linq.Extensions;
using Abp.Net.Mail.Smtp;
using Abp.Notifications;
using Abp.Runtime.Session;
using AutoMapper;
using LearningMpaAbp.Authorization;
using LearningMpaAbp.Authorization.Users;
using LearningMpaAbp.Tasks.Dtos;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic.Core;
using System.Threading.Tasks;

namespace LearningMpaAbp.Tasks
{
/// <summary>
///     Implements <see cref="ITaskAppService" /> to perform task related application functionality.
///     Inherits from <see cref="ApplicationService" />.
///     <see cref="ApplicationService" /> contains some basic functionality common for application services (such as
///     logging and localization).
/// </summary>
public class TaskAppService : LearningMpaAbpAppServiceBase, ITaskAppService
{
private readonly INotificationPublisher _notificationPublisher;
private readonly ISmtpEmailSender _smtpEmailSender;
//These members set in constructor using constructor injection.

private readonly IRepository<Task> _taskRepository;
private readonly IRepository<User, long> _userRepository;
private readonly ITaskManager _taskManager;
private readonly ITaskCache _taskCache;
private readonly IEventBus _eventBus;

/// <summary>
///     In constructor, we can get needed classes/interfaces.
///     They are sent here by dependency injection system automatically.
/// </summary>
public TaskAppService(
IRepository<Task> taskRepository,
IRepository<User, long> userRepository,
ISmtpEmailSender smtpEmailSender,
INotificationPublisher notificationPublisher,
ITaskCache taskCache,
ITaskManager taskManager,
IEventBus eventBus)
{
_taskRepository = taskRepository;
_userRepository = userRepository;
_smtpEmailSender = smtpEmailSender;
_notificationPublisher = notificationPublisher;
_taskCache = taskCache;
_taskManager = taskManager;
_eventBus = eventBus;
}

public TaskCacheItem GetTaskFromCacheById(int taskId)
{
return _taskCache[taskId];
}

public IList<TaskDto> GetAllTasks()
{
var tasks = _taskRepository.GetAll().OrderByDescending(t => t.CreationTime).ToList();
return Mapper.Map<IList<TaskDto>>(tasks);
}

public GetTasksOutput GetTasks(GetTasksInput input)
{
var query = _taskRepository.GetAllIncluding(t => t.AssignedPerson)
.WhereIf(input.State.HasValue, t => t.State == input.State.Value)
.WhereIf(!input.Filter.IsNullOrEmpty(), t => t.Title.Contains(input.Filter))
.WhereIf(input.AssignedPersonId.HasValue, t => t.AssignedPersonId == input.AssignedPersonId.Value);

//排序
if (!string.IsNullOrEmpty(input.Sorting))
query = query.OrderBy(input.Sorting);
else
query = query.OrderByDescending(t => t.CreationTime);

var taskList = query.ToList();

//Used AutoMapper to automatically convert List<Task> to List<TaskDto>.
return new GetTasksOutput
{
Tasks = Mapper.Map<List<TaskDto>>(taskList)
};
}

public PagedResultDto<TaskDto> GetPagedTasks(GetTasksInput input)
{
//初步过滤
var query = _taskRepository.GetAllIncluding(t => t.AssignedPerson)
.WhereIf(input.State.HasValue, t => t.State == input.State.Value)
.WhereIf(!input.Filter.IsNullOrEmpty(), t => t.Title.Contains(input.Filter))
.WhereIf(input.AssignedPersonId.HasValue, t => t.AssignedPersonId == input.AssignedPersonId.Value);

//排序
query = !string.IsNullOrEmpty(input.Sorting) ? query.OrderBy(input.Sorting) : query.OrderByDescending(t => t.CreationTime);

//获取总数
var tasksCount = query.Count();
//默认的分页方式
//var taskList = query.Skip(input.SkipCount).Take(input.MaxResultCount).ToList();

//ABP提供了扩展方法PageBy分页方式
var taskList = query.PageBy(input).ToList();

return new PagedResultDto<TaskDto>(tasksCount, taskList.MapTo<List<TaskDto>>());
}

public async Task<TaskDto> GetTaskByIdAsync(int taskId)
{
//Called specific GetAllWithPeople method of task repository.
var task = await _taskRepository.GetAsync(taskId);

//Used AutoMapper to automatically convert List<Task> to List<TaskDto>.
return task.MapTo<TaskDto>();
}

public TaskDto GetTaskById(int taskId)
{
var task = _taskRepository.Get(taskId);

return task.MapTo<TaskDto>();
}

public void UpdateTask(UpdateTaskInput input)
{
//We can use Logger, it's defined in ApplicationService base class.
Logger.Info("Updating a task for input: " + input);

//获取是否有权限
bool canAssignTaskToOther = PermissionChecker.IsGranted(PermissionNames.Pages_Tasks_AssignPerson);
//如果任务已经分配且未分配给自己，且不具有分配任务权限，则抛出异常
if (input.AssignedPersonId.HasValue && input.AssignedPersonId.Value != AbpSession.GetUserId() &&
!canAssignTaskToOther)
{
throw new AbpAuthorizationException("没有分配任务给他人的权限！");
}

var updateTask = Mapper.Map<Task>(input);
var user = _userRepository.Get(input.AssignedPersonId.Value);
//先执行分配任务
_taskManager.AssignTaskToPerson(updateTask, user);

//再更新其他字段
_taskRepository.Update(updateTask);

}

public void AssignTaskToPerson(AssignTaskToPersonInput input)
{
var task = _taskRepository.Get(input.TaskId);
var user = _userRepository.Get(input.UserId);
_taskManager.AssignTaskToPerson(task, user);
//这里有一个问题就是，当开发人员不知道有这个TaskManager时，依然可以通过直接修改Task的AssignedPersonId属性就行任务分配。

//分配任务成功后，触发领域事件，发送邮件通知
//_eventBus.Trigger(new TaskAssignedEventData(task, user));//由领域服务触发领域事件

}

public int CreateTask(CreateTaskInput input)
{
//We can use Logger, it's defined in ApplicationService class.
Logger.Info("Creating a task for input: " + input);

//判断用户是否有权限
if (input.AssignedPersonId.HasValue && input.AssignedPersonId.Value != AbpSession.GetUserId())
PermissionChecker.Authorize(PermissionNames.Pages_Tasks_AssignPerson);

var task = Mapper.Map<Task>(input);

int result = _taskRepository.InsertAndGetId(task);

//只有创建成功才发送邮件和通知
if (result > 0)
{
if (input.AssignedPersonId.HasValue)
{
var user = _userRepository.Load(input.AssignedPersonId.Value);
//task.AssignedPerson = user;
//var message = "You hava been assigned one task into your todo list.";

//使用领域事件触发发送通知操作
_eventBus.Trigger(new TaskAssignedEventData(task, user));

//TODO:需要重新配置QQ邮箱密码
//_smtpEmailSender.Send("ysjshengjie@qq.com", task.AssignedPerson.EmailAddress, "New Todo item", message);

//_notificationPublisher.Publish("NewTask", new MessageNotificationData(message), null,
//    NotificationSeverity.Info, new[] { task.AssignedPerson.ToUserIdentifier() });
}
}

return result;
}

public void Delete(int id)
{
var task = _taskRepository.Get(id);
if (task != null)
_taskRepository.Delete(task);
}
}
}

2，ITaskAppService 继承IApplicationService

using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic;
using System.Threading.Tasks;
using Abp.Application.Services;
using Abp.Application.Services.Dto;
using Abp.Linq.Extensions;
using LearningMpaAbp.Tasks.Dtos;

namespace LearningMpaAbp.Tasks
{
public interface ITaskAppService : IApplicationService
{
GetTasksOutput GetTasks(GetTasksInput input);

PagedResultDto<TaskDto> GetPagedTasks(GetTasksInput input);

void UpdateTask(UpdateTaskInput input);

int CreateTask(CreateTaskInput input);

Task<TaskDto> GetTaskByIdAsync(int taskId);

TaskDto GetTaskById(int taskId);

void Delete(int taskId);

TaskCacheItem GetTaskFromCacheById(int taskId);

IList<TaskDto> GetAllTasks();
}
}

三，Dto 数据传输对象(Data Transfer Objects)用于应用层和展现层的数据传输

ABP 建议命名 input/ouput 对象类似于 MethodNameInput/MethodNameOutput，对于每个应用服务方法都需要将 Input 和 Output 进行分开定义。甚至你的方法只接
收或者返回一个值，也最好创建相应的 DTO 类型。 这样会使代码有更好的扩展性

using System.Collections.Generic;

namespace LearningMpaAbp.Tasks.Dtos
{
public class GetTasksOutput
{
public List<TaskDto> Tasks { get; set; }
}
}

有一个问题怎么将task实体类转换为dto，这时就需要进行映射了AutoMapper 根据 Task实体创建了 taskDto,并根据命名约定来给
PersonDto 的属性赋值 。

以上。。

参考：http://www.jianshu.com/p/da69ca7b27c6

代码：https://github.com/tianxiangd/LearnAbp