private IEnumerable <LinkResource> CreateLinks(ArticleParameters request,
bool hasPrevious, bool hasNext)
{
var links = new List <LinkResource>
{
new LinkResource(
CreateUri(request, PaginationUriType.CurrentPage),
"self", "GET")
};
if (hasPrevious)
{
links.Add(
new LinkResource(
CreateUri(request, PaginationUriType.PreviousPage),
"previous_page", "GET"));
}
if (hasNext)
{
links.Add(
new LinkResource(
CreateUri(request, PaginationUriType.NextPage),
"next_page", "GET"));
}
return(links);
}
private string CreateUri(ArticleParameters parameters, PaginationUriType uriType)
{
switch (uriType)
{
case PaginationUriType.PreviousPage:
var previours = new
{
PageIndex = parameters.PageIndex - 1,
PageSize = parameters.PageSize,
OrderBy = parameters.OrderBy,
//fields=parameters
};
return(_urlHelper.Link("GetArticles", previours));
case PaginationUriType.NextPage:
var next = new
{
PageIndex = parameters.PageIndex + 1,
PageSize = parameters.PageSize,
OrderBy = parameters.OrderBy,
//fields=parameters
};
return(_urlHelper.Link("GetArticles", next));
default:
var current = new
{
PageIndex = parameters.PageIndex,
PageSize = parameters.PageSize,
OrderBy = parameters.OrderBy,
//fields=parameters
};
return(_urlHelper.Link("GetArticles", current));
}
}
/// <summary>
/// 文章过滤及搜索
/// </summary>
/// <param name="parameters"></param>
/// <returns></returns>
public async Task <PageList <ArticleListViewModel> > GetArticles(ArticleParameters parameters)
{
if (parameters == null)
{
throw new ArgumentNullException(nameof(parameters));
}
var resultList = _articleRepository.GetAll();
var dateTime = DateTime.Now;
//过滤条件，判断枚举是否引用
if (Enum.IsDefined(typeof(DistanceTime), parameters.DistanceTime))
{
switch (parameters.DistanceTime)
{
case DistanceTime.Week:
dateTime = dateTime.AddDays(-7);
break;
case DistanceTime.Month:
dateTime = dateTime.AddMonths(-1);
break;
case DistanceTime.Year:
dateTime = dateTime.AddYears(-1);
break;
}
resultList = resultList.Where(m => m.CreateTime > dateTime);
}
//搜索条件，暂时添加标题和内容
if (!string.IsNullOrWhiteSpace(parameters.SearchStr))
{
parameters.SearchStr = parameters.SearchStr.Trim();
resultList = resultList.Where(m =>
m.Title.Contains(parameters.SearchStr) || m.Content.Contains(parameters.SearchStr));
}
//转换为viewModel
var list = resultList.Select(m => new ArticleListViewModel
{
ArticleId = m.Id,
Title = m.Title,
Content = m.Content,
CreateTime = m.CreateTime,
Account = m.User.Account,
ProfilePhoto = m.User.ProfilePhoto
});
//排序
var mappingDictionary = _propertyMappingService.GetPropertyMapping <ArticleListViewModel, Article>();
list = list.ApplySort(parameters.Orderby, mappingDictionary);
return(await PageList <ArticleListViewModel> .CreatePageMsgAsync(list, parameters.PageNumber, parameters.PageSize));
}
public async Task <PaginatedList <Article> > GetAllArticlesAsync(ArticleParameters request)
{
var query = _context.Articles.AsQueryable();
if (!string.IsNullOrEmpty(request.Title))
{
query = query.Where(r => r.Title.ToLowerInvariant().Contains(request.Title.ToLowerInvariant()));
}
query = query.ApplySort(request.OrderBy, _propertyMappingContainer.Resolve <ArticleViewModel, Article>());
var count = await query.CountAsync();
var data = await query.Skip(request.PageIndex *request.PageSize).Take(request.PageSize).ToListAsync();
return(new PaginatedList <Article>(request.PageIndex, request.PageSize, count, data));
}
//实现HATEOAS集合资源的简单方法，将自身的前一页信息和后一页信息也放到headoas中
private IEnumerable <LinkDto> CreateLinksForArticles(ArticleParameters parameters, bool hasPrevious, bool hasNext)
{
var links = new List <LinkDto>
{
new LinkDto(CreateArticleUrl(parameters, UrlType.CurrentPage), "self", "GET")
};
if (hasPrevious)
{
links.Add(new LinkDto(CreateArticleUrl(parameters, UrlType.PreviousPage), "Previous", "GET"));
}
if (hasNext)
{
links.Add(new LinkDto(CreateArticleUrl(parameters, UrlType.NextPage), "Next", "GET"));
}
return(links);
}
public async Task <IActionResult> Get([FromQuery] ArticleParameters request, [FromHeader(Name = "Accept")] string mediaType)
{
var list = await _articleRepository.GetAllArticlesAsync(request);
var previoustlink = list.GetHasPrevious ? CreateUri(request, PaginationUriType.PreviousPage) : null;
var nextlink = list.GetHasNext ? CreateUri(request, PaginationUriType.NextPage) : null;
var metadata = new
{
PageSize = list.PageSize,
PageIndex = list.PageIndex,
TotalCount = list.TotalCount,
PageCount = list.PageCount,
Previoustlink = previoustlink,
Nextlink = nextlink,
//list.GetHasPrevious
};
//_logger.LogInformation("test");
//throw new Exception("fsf");
Response.Headers.Add("X-Pagination", JsonConvert.SerializeObject(metadata, new JsonSerializerSettings
{
ContractResolver = new CamelCasePropertyNamesContractResolver()
}));//序列化时候变成驼峰规范
var viewList = _mapper.Map <IEnumerable <Article>, IEnumerable <ArticleViewModel> >(list);
var shaped = viewList.ToDynamicIEnumerable(request.Fields);
var shapedLinks = shaped.Select(r =>
{
var dic = r as IDictionary <string, object>;
var articlelinks = CreateLinks((int)dic["Id"], request.Fields);
dic.Add("links", articlelinks);
return(dic);
});
var links = CreateLinks(request, list.GetHasPrevious, list.GetHasNext);
return(Ok(new
{
value = shapedLinks,
links
}));
}
//返回前一页面，后一页，以及当前页的url信息
private string CreateArticleUrl(ArticleParameters parameters, UrlType type)
{
var isDefined = Enum.IsDefined(typeof(DistanceTime), parameters.DistanceTime);
switch (type)
{
case UrlType.PreviousPage:
return(Url.Link(nameof(GetArticles), new
{
fields = parameters.Fields,
orderBy = parameters.Orderby,
pageNumber = parameters.PageNumber - 1,
pageSize = parameters.PageSize,
distanceTime = isDefined ? parameters.DistanceTime.ToString() : null,
searchStr = parameters.SearchStr
}));
case UrlType.NextPage:
return(Url.Link(nameof(GetArticles), new
{
fields = parameters.Fields,
orderBy = parameters.Orderby,
pageNumber = parameters.PageNumber + 1,
pageSize = parameters.PageSize,
distanceTime = isDefined ? parameters.DistanceTime.ToString() : null,
searchStr = parameters.SearchStr
}));
default:
return(Url.Link(nameof(GetArticles), new
{
fields = parameters.Fields,
orderBy = parameters.Orderby,
pageNumber = parameters.PageNumber,
pageSize = parameters.PageSize,
distanceTime = isDefined ? parameters.DistanceTime.ToString() : null,
searchStr = parameters.SearchStr
}));
}
}
public async Task <IActionResult> GetArticles([FromQuery] ArticleParameters parameters)
{
//不存在排序字段则返回400错误
if (!_propertyMappingService.PropertyMappingExist <ArticleListViewModel, Article>(parameters.Orderby))
{
return(BadRequest());
}
//确认是否存在该字段
if (!_propertyCheckService.TypeHasProperties <ArticleListViewModel>(parameters.Fields))
{
return(BadRequest());
}
var list = await _articleService.GetArticles(parameters);
//前后页信息
//var previousPageLink = list.HasPrevious ? CreateArticleUrl(parameters, UrlType.PreviousPage) : null;
//var nextPageLink = list.HasNext ? CreateArticleUrl(parameters, UrlType.NextPage) : null;
var paginationX = new
{
totalCount = list.TotalCount,
pageSize = list.PageSize,
currentPage = list.CurrentPage,
totalPages = list.TotalPages,
//previousPageLink,
//nextPageLink
};
//添加前后页面信息
Response.Headers.Add("Pagination-X", JsonSerializer.Serialize(paginationX, new JsonSerializerOptions
{
Encoder = JavaScriptEncoder.UnsafeRelaxedJsonEscaping
}));
//防止添加hateoas异常
if (!string.IsNullOrWhiteSpace(parameters.Fields))
{
if (!parameters.Fields.ToLowerInvariant().Contains("articleid"))
{
parameters.Fields += ",articleid";
}
}
//结果集数据塑形
var shapedList = list.ShapeDataList(parameters.Fields);
//集合内部元素依次添加links信息
var resultList = shapedList.Select(x =>
{
var articleDict = x as IDictionary <string, object>;
var articleLinks = CreateLinksForArticle((Guid)articleDict["ArticleId"], null);
articleDict.Add("links", articleLinks);
return(articleDict);
});
//为集合资源获取HEATOAS的Links信息
var links = CreateLinksForArticles(parameters, list.HasPrevious, list.HasNext);
//组合信息并返回
var resultListWithLinks = new
{
value = resultList,
links
};
return(Ok(resultListWithLinks));
}
