Module: ApiCursorPagination::Concern

Extended by:
ActiveSupport::Concern
Defined in:
lib/api_cursor_pagination/concern.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#next_page_cursor_id ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def next_page_cursor_id
  @next_page_cursor_id
end

#page_after ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def page_after
  @page_after
end

#page_before ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def page_before
  @page_before
end

#page_size ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def page_size
  @page_size
end

#prev_page_cursor_id ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def prev_page_cursor_id
  @prev_page_cursor_id
end

#total_pages ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def total_pages
  @total_pages
end

#total_size ⇒ Object

Based on jsonapi.org/profiles/ethanresnick/cursor-pagination/



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# File 'lib/api_cursor_pagination/concern.rb', line 43

def total_size
  @total_size
end

Instance Method Details

#page_links_and_meta_data(base_url, query_params) ⇒ Object 



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# File 'lib/api_cursor_pagination/concern.rb', line 118

def page_links_and_meta_data(base_url, query_params)
  if page_size > 0
    cursor = {}
    cursor[:before] = prev_page_cursor_id if prev_page_cursor_id.present?
    cursor[:after] = next_page_cursor_id if next_page_cursor_id.present?
    meta_hash = {
      meta: {
        page: { cursor: cursor, total: total_size, pages: total_pages }
      }
    }
    meta_hash[:links] = {}
    if prev_page_cursor_id.present?
      query_string = query_params.merge(page: { before: prev_page_cursor_id, size: page_size }).to_query
      meta_hash[:links].merge!(prev: "#{base_url}?#{query_string}")
    end
    if next_page_cursor_id.present?
      query_string = query_params.merge(page: { after: next_page_cursor_id, size: page_size }).to_query
      meta_hash[:links].merge!(next: "#{base_url}?#{query_string}")
    end
    meta_hash
  else
    {}
  end
end

#paginate(scope, scope_id_str, row_id_str = scope_id_str) ⇒ Object 



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# File 'lib/api_cursor_pagination/concern.rb', line 94

def paginate(scope, scope_id_str, row_id_str = scope_id_str)
  if page_size > 0
    self.total_size = scope.size
    self.total_pages = total_size / page_size
    self.total_pages += 1 if total_size % page_size > 0

    scope = scope.having("#{scope_id_str} > ?", page_after) if page_after.present?
    scope = scope.having("#{scope_id_str} < ?", page_before) if page_before.present?
    scope = scope.limit(page_size)
    if page_before.present? && page_after.blank?
      scope = scope.order("#{scope_id_str} desc")
      rows = scope.to_a.sort_by{|r| r.send(row_id_str)}
    else
      rows = scope.order(scope_id_str).to_a
    end

    self.next_page_cursor_id = rows.last&.send(row_id_str)
    self.prev_page_cursor_id = rows.first&.send(row_id_str)
    rows
  else
    scope.to_a
  end
end

#validate_and_setup_page_params(page_params) ⇒ Object 



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# File 'lib/api_cursor_pagination/concern.rb', line 47

def validate_and_setup_page_params(page_params)
  @errors ||= []
  self.page_size = 0
  return if page_params.blank?
  
  self.page_size = page_params[:size].to_i
  if page_size < 1
    @errors << {
      title: 'Invalid Parameter.',
      detail: "page[size] is required and must be a positive integer; got #{page_params[:size]}",
      source: { parameter: "page[size]" }
    }
  elsif page_params.has_key?(:sort)
    @errors << {
      title: 'Unsupported Sort.',
      detail: "page[sort] is not supported; got page[sort]=#{page_params[:sort]}",
      source: { parameter: "page[sort]" },
      links: { type: ["https://jsonapi.org/profiles/ethanresnick/cursor-pagination/unsupported-sort"] }
    }
  elsif page_params.has_key?(:before) && page_params.has_key?(:after)
    @errors << {
      title: "Range Pagination Not Supported.",
      detail: "Range pagination not supported; got page[before]=#{page_params[:before]} and page[after]=#{page_params[:after]}",
      links: { type: ["https://jsonapi.org/profiles/ethanresnick/cursor-pagination/range-pagination-not-supported"] }
    }
  elsif page_params.has_key?(:before)
    self.page_before = page_params[:before]
    if self.page_before.blank?
      @errors << {
        title: 'Invalid Parameter.',
        detail: 'page[before] is invalid',
        source: { parameter: 'page[before]' }
      }
    end
  elsif page_params.has_key?(:after)
    self.page_after = page_params[:after]
    if self.page_after.blank?
      @errors << {
        title: 'Invalid Parameter.',
        detail: 'page[after] is invalid',
        source: { parameter: 'page[after]' }
      }
    end
  end

end