Class: Promoted::Ruby::Client::Pager

Inherits:
Object
  • Object
show all
Defined in:
lib/promoted/ruby/client/pager.rb

Instance Method Summary collapse

Instance Method Details

#_sanitize_offsets(retrieval_insertion_offset, paging) ⇒ Object 



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# File 'lib/promoted/ruby/client/pager.rb', line 21

def _sanitize_offsets(retrieval_insertion_offset, paging)
  offset = [0, paging[:offset]].max
  retrieval_insertion_offset = [0, retrieval_insertion_offset].max
  index = [0, offset - retrieval_insertion_offset].max
  return [offset, retrieval_insertion_offset, index]
end

#_validate_paging(insertions, retrieval_insertion_offset, offset, index) ⇒ Object 



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# File 'lib/promoted/ruby/client/pager.rb', line 28

def _validate_paging(insertions, retrieval_insertion_offset, offset, index)
  if offset < retrieval_insertion_offset
    raise InvalidPagingError.new("Invalid page offset (retrieval_insertion_offset #{retrieval_insertion_offset}, offset #{offset})", [])
  end
  if index >= insertions.length
    raise InvalidPagingError.new("Invalid page offset (insertion size #{insertions.length}, index #{index})", [])
  end
end

#apply_paging(insertions, retrieval_insertion_offset, paging = nil) ⇒ Object 



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# File 'lib/promoted/ruby/client/pager.rb', line 37

def apply_paging(insertions, retrieval_insertion_offset, paging = nil)
  if !paging
    paging = {
      :offset => 0,
      :size => insertions.length
    }
  end

  offset, retrieval_insertion_offset, index = _sanitize_offsets(retrieval_insertion_offset, paging)

  begin
    _validate_paging(insertions, retrieval_insertion_offset, offset, index)
  rescue InvalidPagingError => err
    # This is invalid input, stop it before it goes to the server.
    return err.default_insertions_page
  end

  size = paging[:size]
  if size <= 0
    size = insertions.length
  end

  final_insertion_size = [size, insertions.length - index].min
  insertion_page = Array.new(final_insertion_size)
  0.upto(final_insertion_size - 1) {|i|
    request_insertion = insertions[index]
    # Pager returns response insertions.  Create a copy and fill in some of the fields.
    response_insertion = Hash[]
    response_insertion[:content_id] = request_insertion[:content_id]
    response_insertion[:insertion_id] = request_insertion[:insertion_id]
    # TODO - implement retrieval_start.
    response_insertion[:position] = offset
    insertion_page[i] = response_insertion
    index = index + 1
    offset = offset + 1
  }

  return insertion_page
end

#validate_paging(insertions, retrieval_insertion_offset, paging) ⇒ Object 



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# File 'lib/promoted/ruby/client/pager.rb', line 14

def validate_paging(insertions, retrieval_insertion_offset, paging)
  if paging && paging[:offset]
    offset, retrieval_insertion_offset, index = _sanitize_offsets(retrieval_insertion_offset, paging)
    _validate_paging(insertions, retrieval_insertion_offset, offset, index)
  end
end