protected Task <Option <Article, Error> > GetArticleBySlug(string slug) =>
slug.SomeWhen <string, Error>(s => !string.IsNullOrEmpty(s), "The slug must not be empty.")
.Map(s => s.ToLower())
.FlatMapAsync(async s =>
await AllArticlesQueryable
.OrderByDescending(a => a.CreatedAt)
.FirstOrDefaultAsync(a => a.Slug.ToLower() == slug.ToLower())
.SomeNotNull <Article, Error>($"No article with slug '{slug}' was found."));
public Task <Option <ArticleModel[], Error> > GetFeed(string viewingUserId, int limit = 20, int offset = 0) =>
GetUserByIdOrError(viewingUserId)
.MapAsync(async viewingUser =>
{
var followedUserIds = viewingUser
.Following
.Select(f => f.FollowingId)
.ToArray();
var articles = await AllArticlesQueryable
.Where(a => followedUserIds.Contains(a.Author.Id))
.Skip(offset)
.Take(limit)
.ToArrayAsync();
return(await ToArticleModelsAsync(viewingUserId.Some(), articles));
});
