[GEM] Add the pagy_get_count method to the backend

docs/api/backend.md

@@ -72,14 +72,22 @@ self contained custom `pagy` method. (see [Writing your own Pagy methods](#writi
 Sub-method called only by the `pagy` method, it returns the hash of variables used to initialize the Pagy object.
 
 Override it if you need to add or change some variable. For example you may want to add the `:item_name` in order to customize
-the output _(see [How to customize the item name](/docs/how-to.md#customize-the-item-name))_, or even cache the `count`.
+the output _(see [How to customize the item name](/docs/how-to.md#customize-the-item-name))_.
 
 !!!warning Don't remove `:count` and `:page`
-`:count` and `:page` are the only 2 required Pagy core variables, so be careful not to remove them from the returned hash.
+If you override it, remember that `:count` and `:page` are the only 2 required Pagy core variables, so be careful not to remove them from the returned hash.
 !!!
 
 See also the [How To](/docs/how-to.md) page for some usage examples.
 
+==- `pagy_get_count(collection, vars)`
+
+Get the count from the collection, considering also the `:count_args` variable. Override it if you need to calculate the count in some specil way, or cache it.
+
+==- `pagy_get_page(vars)`
+
+Get the `page` from the param ,looking at the `:page_param` variable. See also [Customize the page_param](/docs/how-to.md#customize-the-page-param).
+
 ==- `pagy_get_items(collection, pagy)`
 
 Sub-method called only by the `pagy` method, it returns the page items (i.e. the records belonging to the current page).

docs/how-to.md

@@ -178,7 +178,7 @@ collections in the same action. Depending on the scope of the customization, you
 2. `pagy(scope, page_param: :custom_param)` or `Pagy.new(count:100, page_param: :custom_param)` will be used for a single
    instance (overriding the global default)
 
-You can also override the `pagy_get_vars` if you need some special way to get the page number.
+You can also override the [pagy_get_page](/docs/api/backend.md#pagy-get-page-vars) if you need some special way to get the page number.
 
 ## Customize the link attributes
 
@@ -731,19 +731,13 @@ You have 2 possible solutions in order to improve the performance.
 Depending on the nature of the app, a possible cheap solution would be caching the count of the collection, and Pagy makes that
 really simple.
 
-Pagy gets the collection count through its `pagy_get_vars` method, so you can override it in your controller. Here is an example
+Pagy gets the collection count through its `pagy_get_count` method, so you can override it in your controller. Here is an example
 using the rails cache:
 
 ```ruby controller
-# override the pagy_get_vars method so it will call your cache_count method
-def pagy_get_vars(collection, vars)
-  vars[:count] ||= cache_count(collection)
-  vars[:page]  ||= params[vars[:page_param] || Pagy::DEFAULT[:page_param]]
-  vars
-end
-
-# add Rails.cache wrapper around the count call
-def cache_count(collection)
+# override the pagy_get_count method adding
+# the Rails.cache wrapper around the count call
+def pagy_get_count(collection, _vars)
   cache_key = "pagy-#{collection.model.name}:#{collection.to_sql}"
   Rails.cache.fetch(cache_key, expires_in: 20 * 60) do
     collection.count(:all)

gem/lib/pagy/backend.rb

@@ -18,12 +18,17 @@ def pagy(collection, vars = {})
     # You may need to override the count call for non AR collections
     def pagy_get_vars(collection, vars)
       pagy_set_items_from_params(vars) if defined?(ItemsExtra)
-      count_args = vars[:count_args] || DEFAULT[:count_args]
-      vars[:count] ||= (count = collection.count(*count_args)).is_a?(Hash) ? count.size : count
+      vars[:count] ||= pagy_get_count(collection, vars)
       vars[:page]  ||= pagy_get_page(vars)
       vars
     end
 
+    # Get the count from the collection
+    def pagy_get_count(collection, vars)
+      count_args = vars[:count_args] || DEFAULT[:count_args]
+      (count     = collection.count(*count_args)).is_a?(Hash) ? count.size : count
+    end
+
     # Get the page integer from the params
     # Overridable by the jsonapi extra
     def pagy_get_page(vars)