Class: RESTFramework::Paginators::PageNumberPaginator

Inherits:
BasePaginator
  • Object
show all
Defined in:
lib/rest_framework/paginators/page_number_paginator.rb

Overview

A simple paginator based on page numbers.

Example: example.com/api/users/?page=3&page_size=50

Instance Method Summary collapse

Constructor Details

#initialize(**kwargs) ⇒ PageNumberPaginator

Returns a new instance of PageNumberPaginator.



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# File 'lib/rest_framework/paginators/page_number_paginator.rb', line 5

def initialize(**kwargs)
  super
  # Exclude any `select` clauses since that would cause `count` to fail with a SQL `SyntaxError`.
  @count = @data.except(:select).count
  @page_size = self._page_size

  @total_pages = @count / @page_size
  @total_pages += 1 if @count % @page_size != 0
end

Instance Method Details

#_page_size ⇒ Object 



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# File 'lib/rest_framework/paginators/page_number_paginator.rb', line 15

def _page_size
  page_size = nil

  # Get from context, if allowed.
  if @controller.page_size_query_param
    if page_size = @controller.params[@controller.page_size_query_param].presence
      page_size = page_size.to_i
    end
  end

  # Otherwise, get from config.
  if !page_size && @controller.page_size
    page_size = @controller.page_size
  end

  # Ensure we don't exceed the max page size.
  if @controller.max_page_size && page_size > @controller.max_page_size
    page_size = @controller.max_page_size
  end

  # Ensure we return at least 1.
  return page_size.zero? ? 1 : page_size
end

#get_page(page_number = nil) ⇒ Object

Get the page and return it so the caller can serialize it.



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# File 'lib/rest_framework/paginators/page_number_paginator.rb', line 40

def get_page(page_number=nil)
  # If page number isn't provided, infer from the params or use 1 as a fallback value.
  unless page_number
    page_number = @controller&.params&.[](@controller.page_query_param&.to_sym)
    if page_number.blank?
      page_number = 1
    else
      page_number = page_number.to_i
      if page_number.zero?
        page_number = 1
      end
    end
  end
  @page_number = page_number

  # Get the data page and return it so the caller can serialize the data in the proper format.
  page_index = @page_number - 1
  return @data.limit(@page_size).offset(page_index * @page_size)
end

#get_paginated_response(serialized_page) ⇒ Object

Wrap the serialized page with appropriate metadata. TODO: include links.



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# File 'lib/rest_framework/paginators/page_number_paginator.rb', line 61

def get_paginated_response(serialized_page)
  page_query_param = @controller.page_query_param
  base_params = @controller.params.to_unsafe_h
  next_url = if @page_number < @total_pages
    @controller.url_for({**base_params, page_query_param => @page_number + 1})
  end
  previous_url = if @page_number > 1
    @controller.url_for({**base_params, page_query_param => @page_number - 1})
  end

  return {
    count: @count,
    page: @page_number,
    page_size: @page_size,
    total_pages: @total_pages,
    next: next_url,
    previous: previous_url,
    results: serialized_page,
  }.compact
end