private static NavigationCursor GetForwardCursor(IList <Story> stories, int pageSize)
{
if (0 == stories.Count)
{
return(null);
}
if (pageSize > stories.Count)
{
return(null);
}
var id = stories[stories.Count - 1].Id;
return(NavigationCursor.Forward(id, pageSize));
}
public async Task <IActionResult> Get(string page, [FromCommaSeparatedQuery(Name = "include")] IEnumerable <string> includes)
{
var flags = EnumFlags.Parse <StoryIncludes>(includes);
var query = new GetStoriesListQuery(User)
{
IncludeAuthors = StoryIncludes.Authors == (flags & StoryIncludes.Authors),
IncludeComments = StoryIncludes.Comments == (flags & StoryIncludes.Comments),
Cursor = (null != page && NavigationCursorEncoder.TryParse(page, out var cursor))
? cursor
: NavigationCursor.Forward(0, blogSettings.PageSize)
};
var result = await mediator.Send(query, HttpContext.RequestAborted);
if (false == result.IsSuccess())
{
foreach (var exception in result.Exceptions)
{
logger.LogError(exception, "[StoriesController.Get]");
}
return(BadRequest(result.Exceptions));
}
var include = EnumFlags.ToQueryString(flags);
string backward = null;
string forward = null;
if (null != result.Backward)
{
backward = Url.Action("Get", "Stories", new
{
page = NavigationCursorEncoder.ToEncodedString(result.Backward),
include = include.ToString()
});
}
if (null != result.Forward)
{
forward = Url.Action("Get", "Stories", new
{
page = NavigationCursorEncoder.ToEncodedString(result.Forward),
include = include.ToString()
});
}
return(Ok(new ListResult <StoryModel, ResourcesMetaInfo>
{
Data = result.Select(story =>
{
var model = mapper.Map <StoryModel>(story);
model.Author = result.Authors.FindIndex(story.Author);
return model;
}),
Meta = new ResourcesMetaInfo
{
Resources = new AuthorsResource
{
Authors = result.Authors.Select(author => mapper.Map <AuthorModel>(author))
},
Navigation = new Navigation
{
Previous = backward,
Next = forward
}
}
}));
}
}