/// <summary>
/// 为集合资源添加HATEOAS的LINKS
/// </summary>
/// <param name="postResourceParameters"></param>
/// <param name="hasPrevious">是否具有前一页属性</param>
/// <param name="hasNext">是否具有后一页属性</param>
/// <returns>LinkResource集合</returns>
private IEnumerable <LinkResource> CreateLinksForPosts(PostQueryParameters postResourceParameters,
bool hasPrevious, bool hasNext)
{
var links = new List <LinkResource>
{
new LinkResource(
CreatePostUri(postResourceParameters, PaginationResourceUriType.CurrentPage, "getPosts"),
"self", "GET")
};
if (hasPrevious)
{
links.Add(
new LinkResource(
CreatePostUri(postResourceParameters, PaginationResourceUriType.PreviousPage, "getPosts"),
"previous_page", "GET"));
}
if (hasNext)
{
links.Add(
new LinkResource(
CreatePostUri(postResourceParameters, PaginationResourceUriType.NextPage, "getPosts"),
"next_page", "GET"));
}
return(links);
}
/// <summary>
/// 生成前一页，后一页，当前页的URI链接方法
/// </summary>
/// <param name="parameters">页面的元数据</param>
/// <param name="uriType">URI类型</param>
/// <param name="actionName">需要调用的ActionName</param>
/// <returns></returns>
private string CreatePostUri(PostQueryParameters parameters, PaginationResourceUriType uriType, string actionName)
{
switch (uriType)
{
case PaginationResourceUriType.PreviousPage:
var previousParameters = new
{
pageIndex = parameters.PageIndex - 1,
pageSize = parameters.PageSize,
orderBy = parameters.OrderBy,
fields = parameters.Fields
};
return(urlHelper.Link(actionName, previousParameters));
case PaginationResourceUriType.NextPage:
var nextParameters = new
{
pageIndex = parameters.PageIndex + 1,
pageSize = parameters.PageSize,
orderBy = parameters.OrderBy,
fields = parameters.Fields
};
return(urlHelper.Link(actionName, nextParameters));
default:
var currentParameters = new
{
pageIndex = parameters.PageIndex,
pageSize = parameters.PageSize,
orderBy = parameters.OrderBy,
fields = parameters.Fields
};
return(urlHelper.Link(actionName, currentParameters));
}
}
public async Task <IActionResult> Get(PostQueryParameters postQueryParameters)
{
#region 参数合法性判断
//排序字段合法性判断
if (!string.IsNullOrWhiteSpace(postQueryParameters.OrderBy) &&
!propertyMappingContainer.ValidateMappingExistsFor <PostResource, Post>(postQueryParameters.OrderBy))
{
return(BadRequest("排序属性映射关系不存在，或不可通过该排序属性排序"));
}
//塑形字段合法性判断
if (!string.IsNullOrWhiteSpace(postQueryParameters.Fields) &&
!typeHelperService.TypeHasProperties <PostResource>(postQueryParameters.Fields))
{
return(BadRequest("传入的塑形属性不合法"));
}
#endregion
//返回带有元数据的PaginatedList数据
var postsWithMateData = await postRepository.GetAllPostsAsync(postQueryParameters);
//将posts集合映射为PostResource集合，取出其中的post数据集合
var postResources = mapper.Map <IEnumerable <Post>, IEnumerable <PostResource> >(postsWithMateData);
//针对ResourceModel进行属性塑形
var shapedPostResources = postResources.ToDynamicIEnumerable(postQueryParameters.Fields);
var previousPageLink = postsWithMateData.HasPrevious ? CreatePostUri(postQueryParameters, PaginationResourceUriType.PreviousPage, "GetPosts") : null;
var nextPageLink = postsWithMateData.HasNext ? CreatePostUri(postQueryParameters, PaginationResourceUriType.NextPage, "GetPosts") : null;
#region 提取元数据，并将该数据添加到响应Response自定义X-Pagination的Header中
//提取元数据
var mate = new
{
postsWithMateData.PageSize,
postsWithMateData.PageIndex,
postsWithMateData.TotalItemsCount,
postsWithMateData.PageCount,
previousPageLink,
nextPageLink
};
//将翻页元数据添加到响应Header的X-Pagination中
Response.Headers.Add("X-Pagination", JsonConvert.SerializeObject(mate, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver() //将所有mate元数据属性首字母小写返回
}));
#endregion
//logger.LogError("测试的错误日志记录");
//throw new Exception("发生了错误");
return(Ok(shapedPostResources));
}
public async Task <PaginatedList <Post> > GetAllPostsAsync(PostQueryParameters postQueryParameters)
{
var query = myContext.Posts.AsQueryable();
#region 根据需求 过滤相关字段
if (!string.IsNullOrEmpty(postQueryParameters.Title))
{
var title = postQueryParameters.Title.Trim().ToLowerInvariant();
//直接检索
//query = query.Where(x => x.Title.ToLowerInvariant() == title);
//模糊查询
query = query.Where(x => x.Title.ToLowerInvariant().Contains(title));
//将pageindex设置为第一页起始，防止出现检索的数据不显示的问题
//需要考虑一下怎么解决
//postQueryParameters.PageIndex = 0;
}
#endregion
//query = query.OrderBy(x => x.id);
//传入参数，实现属性排序，传入需要排序ResourceModel的属性
query = query.ApplySort(postQueryParameters.OrderBy, propertyMappingContainer.Resolve <PostResource, Post>());
var count = await query.CountAsync();
var data = await query
.Skip(postQueryParameters.PageIndex *postQueryParameters.PageSize)
.Take(postQueryParameters.PageSize)
.ToListAsync();
var paginatedList = new PaginatedList <Post>(postQueryParameters.PageIndex, postQueryParameters.PageSize, count, data);
return(paginatedList);
//return await myContext.Posts.ToListAsync();
}
public async Task <IActionResult> GetPostsHateoas(PostQueryParameters postQueryParameters)
{
#region 参数合法性判断
//排序字段合法性判断
if (!string.IsNullOrWhiteSpace(postQueryParameters.OrderBy) &&
!propertyMappingContainer.ValidateMappingExistsFor <PostResource, Post>(postQueryParameters.OrderBy))
{
return(BadRequest("排序属性映射关系不存在，或不可通过该排序属性排序"));
}
//塑形字段合法性判断
if (!string.IsNullOrWhiteSpace(postQueryParameters.Fields) &&
!typeHelperService.TypeHasProperties <PostResource>(postQueryParameters.Fields))
{
return(BadRequest("传入的塑形属性不合法"));
}
#endregion
//返回带有元数据的PaginatedList数据
var postsWithMateData = await postRepository.GetAllPostsAsync(postQueryParameters);
//将posts集合映射为PostResource集合，取出其中的post数据集合
var postResources = mapper.Map <IEnumerable <Post>, IEnumerable <PostResource> >(postsWithMateData);
//针对ResourceModel进行属性塑形
var shapedPostResources = postResources.ToDynamicIEnumerable(postQueryParameters.Fields);
#region 针对每个postResource添加HATEOAS的LINKS属性
var shapedWithLinks = shapedPostResources.Select(x =>
{
var dict = x as IDictionary <string, object>;
var postLinks = CreateLinksForPost((int)dict["id"], postQueryParameters.Fields);
dict.Add("links", postLinks);
return(dict);
});
#endregion
#region 针对整个postsResource添加HATEOAS的Links属性
var links = CreateLinksForPosts(postQueryParameters, postsWithMateData.HasPrevious, postsWithMateData.HasNext);
var result = new
{
values = shapedWithLinks,
links
};
#endregion
#region 提取元数据，并将该数据添加到响应Response自定义X-Pagination的Header中
//提取元数据
var mate = new
{
postsWithMateData.PageSize,
postsWithMateData.PageIndex,
postsWithMateData.TotalItemsCount,
postsWithMateData.PageCount
};
//将翻页元数据添加到响应Header的X-Pagination中
Response.Headers.Add("X-Pagination", JsonConvert.SerializeObject(mate, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver() //将所有mate元数据属性首字母小写返回
}));
#endregion
//logger.LogError("测试的错误日志记录");
//throw new Exception("发生了错误");
return(Ok(result));
}
