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[Back to Guides](../README.md)
# How to add pagination links
### JSON API adapter
Pagination links will be included in your response automatically as long as
the resource is paginated and if you are using the ```JsonApi``` adapter.
If you want pagination links in your response, use [Kaminari](https://github.com/amatsuda/kaminari)
or [WillPaginate](https://github.com/mislav/will_paginate).
Although the other adapters do not have this feature, it is possible to
implement pagination links to `JSON` adapter. For more information about it,
please check our docs.
###### Kaminari examples
```ruby
#array
@posts = Kaminari.paginate_array([1, 2, 3]).page(3).per(1)
render json: @posts
#active_record
@posts = Post.page(3).per(1)
render json: @posts
```
###### WillPaginate examples
```ruby
#array
@posts = [1,2,3].paginate(page: 3, per_page: 1)
render json: @posts
#active_record
@posts = Post.page(3).per_page(1)
render json: @posts
```
```ruby
ActiveModelSerializers.config.adapter = :json_api
```
ex:
```json
{
"data": [
{
"type": "articles",
"id": "3",
"attributes": {
"title": "JSON API paints my bikeshed!",
"body": "The shortest article. Ever.",
"created": "2015-05-22T14:56:29.000Z",
"updated": "2015-05-22T14:56:28.000Z"
}
}
],
"links": {
"self": "http://example.com/articles?page[number]=3&page[size]=1",
"first": "http://example.com/articles?page[number]=1&page[size]=1",
"prev": "http://example.com/articles?page[number]=2&page[size]=1",
"next": "http://example.com/articles?page[number]=4&page[size]=1",
"last": "http://example.com/articles?page[number]=13&page[size]=1"
}
}
```
ActiveModelSerializers pagination relies on a paginated collection with the methods `current_page`, `total_pages`, and `size`, such as are supported by both [Kaminari](https://github.com/amatsuda/kaminari) or [WillPaginate](https://github.com/mislav/will_paginate).
### JSON adapter
If you are not using `JSON` adapter, pagination links will not be included automatically, but it is possible to do so using `meta` key.
Add this method to your base API controller.
```ruby
def pagination_dict(collection)
{
current_page: collection.current_page,
next_page: collection.next_page,
prev_page: collection.prev_page, # use collection.previous_page when using will_paginate
total_pages: collection.total_pages,
total_count: collection.total_count
}
end
```
Then, use it on your render method.
```ruby
render json: posts, meta: pagination_dict(posts)
```
ex.
```json
{
"posts": [
{
"id": 2,
"title": "JSON API paints my bikeshed!",
"body": "The shortest article. Ever."
}
],
"meta": {
"current_page": 3,
"next_page": 4,
"prev_page": 2,
"total_pages": 10,
"total_count": 10
}
}
```
You can also achieve the same result if you have a helper method that adds the pagination info in the meta tag. For instance, in your action specify a custom serializer.
```ruby
render json: @posts, each_serializer: PostPreviewSerializer, meta: meta_attributes(@posts)
```
```ruby
#expects pagination!
def meta_attributes(collection, extra_meta = {})
{
current_page: collection.current_page,
next_page: collection.next_page,
prev_page: collection.prev_page, # use collection.previous_page when using will_paginate
total_pages: collection.total_pages,
total_count: collection.total_count
}.merge(extra_meta)
end
```
### Attributes adapter
This adapter does not allow us to use `meta` key, due to that it is not possible to add pagination links.
|
