学习笔记4: HATEOAS

动态类型实现HATEOAS ,提供出超链接等属性,Controller修改一些方法

1.对于单个资源可以用ExpandoObject

2.对于集合资源使用匿名类.

实现:

1.新建一个类:LinkResource.cs,实现3个属性

    public class LinkResource
    {
        public LinkResource(string href, string rel, string method)
        {
            Href = href;
            Rel = rel;
            Method = method;
        }

        public string Href { get; set; }
        public string Rel { get; set; }
        public string Method { get; set; }
    }

2.在PostController.cs添加方法

private IEnumerable<LinkResource> CreateLinksForPost(int id, string fields = null)
        {
            var links = new List<LinkResource>();

            if (string.IsNullOrWhiteSpace(fields))
            {
                links.Add(
                    new LinkResource(
                        _urlHelper.Link("GetPost", new { id }), "self", "GET"));
            }
            else
            {
                links.Add(
                    new LinkResource(
                        _urlHelper.Link("GetPost", new { id, fields }), "self", "GET"));
            }

            links.Add(
                new LinkResource(
                    _urlHelper.Link("DeletePost", new { id }), "delete_post", "DELETE"));

            return links;
        }

        private IEnumerable<LinkResource> CreateLinksForPosts(PostParameters postResourceParameters,
            bool hasPrevious, bool hasNext)
        {
            var links = new List<LinkResource>
            {
                new LinkResource(
                    CreatePostUri(postResourceParameters, PaginationResourceUriType.CurrentPage),
                    "self", "GET")
            };

            if (hasPrevious)
            {
                links.Add(
                    new LinkResource(
                        CreatePostUri(postResourceParameters, PaginationResourceUriType.PreviousPage),
                        "previous_page", "GET"));
            }

            if (hasNext)
            {
                links.Add(
                    new LinkResource(
                        CreatePostUri(postResourceParameters, PaginationResourceUriType.NextPage),
                        "next_page", "GET"));
            }

            return links;
        }

其他: [HttpGet("{id}")]  修改为  [HttpGet("{id}",Name="GetPost")

 Controller修改  单笔返回数据

原代码为:

            var postResource = _mapper.Map<Post, PostResource>(post);

            var shapedPostResource = postResource.ToDynamic(fields);

            return Ok(shapedPostResource);

修改完成后的代码为:
            var postResource = _mapper.Map<Post, PostResource>(post);

            var shapedPostResource = postResource.ToDynamic(fields);

            var links = CreateLinksForPost(id, fields);

            var result = shapedPostResource as IDictionary<string, object>;

            result.Add("links", links);

            return Ok(result);

列表返回数据修改增加连接等参数

原来是
           var shapedPostResource = postResources.ToDynamicIEnumerable(postParameters.Fields);
返回 shapedPostResource 

增加:
  var shapedWithLins = shapedPostResource.Select(x =>
            {
                var dict = x as IDictionary<string, object >;
                var links = CreateLinksForPost((int)dict["Id"], postParameters.Fields);
                dict.Add("links", links);
                return dict;
            });

返回改为 shapedWithLins