public IResult <Pagination <TSource> > Paginate
(
IEnumerable <TSource> items,
IPaginationInstruction paginationInstruction
)
{
var limit = paginationInstruction.Limit;
var maxLimit = paginationInstruction.MaxLimit;
var offset = paginationInstruction.Offset;
var sort = paginationInstruction.Sort;
if (limit < 1)
{
return(ResultFactory
.Failure($"The limit parameter is expected to be a positive number (max: {maxLimit})."));
}
if (limit > maxLimit)
{
return(ResultFactory
.Failure($"The limit parameter must not exceed what is max allowed (max: {maxLimit})."));
}
if (offset < 0)
{
return(ResultFactory
.Failure("The offset parameter is expected to be a non-negative number."));
}
var sortDirectives = SortDirective
.GetSortDirectivesFrom(sort);
if (sortDirectives == null)
{
return(ResultFactory
.Failure("The sort parameter contains invalid directives (expected format: 'property[:asc|desc][,property..]', e.g. 'property1,property2:desc')."));
}
var invalidSortFields = sortDirectives
.Where(x => !_sorters.ContainsKey(x.Property))
.Select(x => x.Property)
.ToList();
if (invalidSortFields.Any())
{
return(ResultFactory
.Failure($"The sort parameter contains directives for nonexistent fields ('${string.Join("', '", invalidSortFields)}')."));
}
var paginated = Sort(items, sortDirectives)
.Skip(offset)
.Take(limit)
.ToList();
var pagination = new Pagination <TSource>(paginated, limit, offset, sort, items.Count());
return(ResultFactory
.Success(pagination));
}
public string BuildListMessagesLinkFor
(
IPaginationInstruction paginationInstruction
)
=> BuildLinkFor(new
{
limit = paginationInstruction.Limit,
offset = paginationInstruction.Offset,
sort = paginationInstruction.Sort
});