Duffel.Page (Duffel v0.1.0)

Copy Markdown View Source

One page of results from a Duffel list endpoint.

The Duffel API uses cursor pagination: pass :after_cursor as the after parameter to fetch the next page. after_cursor is nil on the final page.

To iterate over all pages lazily, use the stream/2 function on the resource module instead, e.g. Duffel.OfferRequests.stream/2. To walk the pages yourself — to checkpoint between them, say — has_more?/1 and next_params/2 do the cursor bookkeeping:

def each_page(client, params) do
  {:ok, page} = Duffel.Orders.list(client, params)
  handle(page.data)

  case Duffel.Page.next_params(page, params) do
    nil -> :done
    next -> each_page(client, next)
  end
end

Summary

Types

t()

Functions

has_more?(page)

Says whether another page follows this one.

next_params(page, params \\ [])

Builds the parameters that fetch the page after this one.

Types

t()

@type t() :: %Duffel.Page{
  after_cursor: String.t() | nil,
  before_cursor: String.t() | nil,
  data: [map()],
  limit: pos_integer() | nil
}

Functions

has_more?(page)

@spec has_more?(t()) :: boolean()

Says whether another page follows this one.

Examples

iex> Duffel.Page.has_more?(%Duffel.Page{after_cursor: "cur_2"})
true

iex> Duffel.Page.has_more?(%Duffel.Page{after_cursor: nil})
false

next_params(page, params \\ [])

@spec next_params(t(), keyword() | map()) :: map() | nil

Builds the parameters that fetch the page after this one.

Pass the parameters you used for this page and the after cursor is merged in, keeping your filters. Returns nil on the last page, so a case can drive the loop:

case Duffel.Page.next_params(page, sort: "total_amount") do
  nil -> :done
  params -> Duffel.Offers.list(client, params)
end

Examples

iex> Duffel.Page.next_params(%Duffel.Page{after_cursor: "cur_2"}, limit: 50)
%{"limit" => 50, "after" => "cur_2"}

iex> Duffel.Page.next_params(%Duffel.Page{after_cursor: nil}, limit: 50)
nil