How do I page, a json result? Using scrivener

Phoenix Forum Questions / Help
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1

I am currently wanting to page a json result, starting from a function.

I know scrivener_ecto and scrivener_html.

However I am not able to make this pagination.
Can you help me??

below is my files

Controller

  def index(conn, _params) do
    result_list = listresult()
    render(conn, "index.html", result_list: result_list)
  end

The result of this function
and a json.

[
 %{
    e_tag: "\"5bd0dca2b5ba0510f5e39dc6f156ca97\"",
    key: "tttgz.txt",
    last_modified: "2018-01-03T19:56:56.000Z",
    size: "9049",
    storage_class: "STANDARD"
  },
  %{
    e_tag: "\"491ac9e6534f501728f48a1d400e174b-31\"",
    key: "tttgz2.txt",
    last_modified: "2018-01-03T19:57:08.000Z",
    size: "253552582",
    storage_class: "STANDARD"
  },
  %{
    e_tag: "\"6bc18d8a4f7f56783501ed610dbec22c-91\"",
    key: "tttgz3.txt",
    last_modified: "2018-01-03T20:04:41.000Z",
    size: "756647736",
    ...
  },
  %{
    e_tag: "\"3c32b2bb5f6a9f1c791b4a1a03b036bc-22\"",
    key: "tttgz4.txt",
    last_modified: "2018-01-03T20:25:56.000Z",
    ...
  },
  %{
    e_tag: "\"e560197c5396c82760453258af88756b-451\"",
    key: "tttgz5.txt",
    last_modified: "2018-01-03T20:30:15.000Z",
    ...
  },
  %{
    e_tag: "\"15e99185d86395c3cd2a4e38a9e342f8-27\"",
    key: "tttgz6.txt",
    ...
  },
  %{e_tag: "\"455b1d90c0a1d2c38f842d19f5c77609-36\"", ...},
  %{...}, 
  ...
]

always when I will access the page using the scrivener
he returns this error to me

protocol Scrivener.Paginater not implemented for [%{e_tag: "\"537f647fa84fd18d1e7ec1bb23e2fb40-1\""

So the question is?

How do I page this json result?

2

You can manually build %Scrivener.Page{} structs.

3

would you have an example to show me, how would it look?

4

Something like that:

%Scrivener.Page{
  entries: Enum.take(result, 10),
  page_number: 1,
  page_size: 10,
  total_entries: length(result),
  total_pages: Float.ceil(length(result) / 10)
}
5

Really that way, I was able to add pagination_links, without errors.
However, by clicking on button 2, 3, 4 …
It does not update the values.
Could you tell me what it can be?

def index(conn, _params) do
    result_list = listresult()

    test = %Scrivener.Page{
      entries: Enum.take(result_list, 10),
      page_number: 1,
      page_size: 10,
      total_entries: length(result_list),
      total_pages: Float.ceil(length(result_list) / 10)
    }


    render(conn, "index.html", test: test)
  end
6

You’ll need to make sure to update the Enum.take and page_number depending on which page you want to serve.

7

I believe this is the most difficult thing, right?

Being able to treat these values, because as I am not using Repo.paginate.

8

Not really. The page is in the params your controller action does receive (for page 2, …). Convert it to an integer and you got the page.

9

As you can see,

I put the page number, but how do I update the entries?

Whenever I click on the page numbers, the same values always remain.


 def index(conn, params) do
    result_list = listresult()
    number_page = Map.get(params, "page") |> String.to_integer()

    test = %Scrivener.Page{
      entries: Enum.take(result_list, 10),
      page_number: number_page,
      page_size: 10,
      total_entries: length(result_list),
      total_pages: Float.ceil(length(result_list) / 10)
    }

    IO.inspect(result_list)
    IO.inspect(params)
    render(conn, "index.html", test: test)
  end
10

You changed only one of the things I said need changing. You can’t just always Enum.take the first 10 items. You’ll need to the take the 10 items, which shall be shown for the current page.
result_list |> Enum.drop(number_page - 1 * 10) |> Enum.take(10)

11

So it worked.


  def index(conn, params) do
    result_list = listresult()
    number_page = Map.get(params, "page") |> String.to_integer()

    test = %Scrivener.Page{
      entries: result |> Enum.drop(number_page - 1 * 1) |> Enum.take(10),
      page_number: number_page,
      page_size: 10,
      total_entries: length(result_list),
      total_pages: Float.ceil(length(result_list) / 10)
    }

    IO.inspect(result_list)
    IO.inspect(params)
    render(conn, "index.html", test: test)
  end

When accessing from page 1 to 14 it works perfectly.
But when I access the page 15

http://localhost:4000/backups?page=15
Retorna este erro.

Request: GET /backups?page=15
** (exit) an exception was raised:
** (ArgumentError) ranges (first…last) expect both sides to be integers, got: 11…20.0
(elixir 1.10.4) lib/range.ex:63: Range.new/2
(scrivener_html 1.8.1) lib/scrivener/html.ex:511: Scrivener.HTML.page_number_list/4
(scrivener_html 1.8.1) lib/scrivener/html.ex:473: Scrivener.HTML.raw_pagination_links/2
(scrivener_html 1.8.1) lib/scrivener/html.ex:214: Scrivener.HTML._pagination_links/2

12

I managed to make it work, with your help
In this way

  def index(conn, params) do
    result_list = listresult()
    number_page = Map.get(params, "page") |> String.to_integer()

    IO.inspect(number_page)

    test = %Scrivener.Page{
      entries: result |> Enum.drop(number_page - 1 * 1) |> Enum.take(10),
      page_number: number_page,
      page_size: 10,
      total_entries: length(result_list),
      total_pages: Kernel.trunc(Float.ceil(length(result_list) / 10))
    }

    render(conn, "index.html", test: test)
  end

But I have a problem, every page that I go through.
I see that some files are repeated.
What do you think it can be?

13

Did you manage to make it work eventually?