#will_paginate

[aboutlinux]

Como paginar en Rails 5

Como paginar en Rails 5

El presente artículo se basa en el articulo de Bala Paranj, mejor dicho es una traducción del mismo.

Me pareció muy intersante y de gran utilidad.

Pasos

Usted puede bajar el código fuente desde Paginación en Rails, que está traducido, o desde el repositorio original wpag.

Paso 1

Añada la gema al archivo Gemfile.

gem 'will_paginate'

Luego ejecute

bundle

Paso 2

Modifique el controlador de Tareas

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[proggr-blog]

Rails 4: Paginating an Array from Subset of Active Record Results With will_paginate

I’m working on a rollout for a new CMS and bumped into this issue last minute that took a bit longer to track down an answer for than I thought it would so I’m adding it here in the hopes someone else stumbles into an answer quicker than I did. 

The Scenario You’ve loaded your result set and potentially cached it with Redis or some other key value store so you have access to it as an array rather than an ActiveRecord collection. You have the number of total entires, but can’t successfully paginate the array results because will_paginate seems to require you have the complete result set handy rather than a subset of it so it either doesn’t render your list items or if you leave off the current page number it renders but always assumes its page 1. Its assumed you’ve already figured out that you’ll need to add the following either in your controller or an initializer to make will_paginate work with array collections. 

require 'will_paginate/array'

Scenario Breakdown

will_paginate expects the collection being paginated to contain the complete result set, and will populate the list of page numbers based on a combination of the current_page, per_page, and total_entries values. The issue with this is that if your array only contains the subset you want to display, it would represent the first X (X = # per_page) records in the array, and for all pages other than page 1 it would try to look into the chunk of the array corresponding to that page and find nothing (since you only have the subset you want to display) and your list would render as if it were an empty set. 

If you leave out the current page in this situation, it defaults to 1 which means it will work since its looking for the first X records which would be the results you want to display, but in this context the viewhelper doesn’t know you’re not really on page 1 and will make every page render with page 1 as the current focus which makes the ‘Next’ and ‘Previous’ links essentially useless. 

The Fix

At first the only solution I could think of was to populate an array with enough elements to fool it into thinking the complete result set was present and then slicing the results into the right spot but with 100k articles potentially making up the results that’s a horrible solution. 

After enough searching the real fix in the end is actually pretty simple and just required a paginate function to be added to my articles_controller. 

    def paginate(articles,page,limit,total_entries)            @articles = WillPaginate::Collection.create(page, limit, total_entries) do |pager|               pager.replace(articles)            end        end      

This function accepts the subset of articles you want to display as an array, the current page number, the limit, and the total number of entries. Then rather than relying on the default constructor, it passes in the page, limit, and total_entries to give the viewhelper what it needs to work and then replaces the values of the current page with the array of articles you pass it, skipping the need for it to chunk through a massive array for the 20 or so articles you actually wanted. 

Hope this helps someone :). And with that, back to the deployment.  

[sugi1119]

will_paginate for Array

When I applied pagination with will_paginate, so many errors were occurred.  will_paginate complain about:  No method (paginate) for 1) NIL class 2) Array  3) forgot to pass the object  so on, so on...  I installed the latest version of will_paginate(gem 'will_paginate', '~> 3.0.5').  So, paginate for array class is covered in will_paginate according to the documentation: https://github.com/mislav/will_paginate/wiki/Troubleshooting

But still, the issues kept occurred. So, I had tried:  1) In config/ initializers/will_paginate_array.rb  I thought will_paginate did not read the size of array, So.. change the size as below: 

Array.class_eval do  def paginate(page = 1, per_page = 20)    page = 1 if page.blank?      WillPaginate::Collection.create(page, per_page, @flickr_images.length) do |pager| pager.replace @flickr_images.length    end  end end

No joy.  2) Add require 'will_paginate/array' in will_paginate_array.rb (in the documentation, it does not need to add since already function is there...)  No joy again. 

3) Tried to add @photos in the paginate method.  photos = flickr.photos.search(text: text, sort: "relevance", per_page: 500) @photos = flickr.paginate(page: params[:page], per_page: 50) No joy -- no paginate method for this  4) put @photos = flickr.paginate(page: params[:page], per_page: 50) in index in controller - no joy. And change this to my search method in controller. no joy. no joy, no joy with infinity loop.  5) Finally, my mentor told me that I should not double mentioned will_paginate for this pagination to array. In 1) and 2), I left there both. It made some conflicts.  Took off the array function part and leave only require 'will_paginate/array' with require 'will_paginate/collection'.  Also, @images = flickr.paginate(page: params[:page], per_page: 50) in search method in controller.  Then, happy paginate now!  It took more than 3days to find out.  My mentor said “Don’t get how to, Do understand WHY”. 

[joffee-blog-blog]

Simple angular pagination using will_paginate

Over the past month I have been working on re-writing the search for http://www.tunefruit.com using angularjs.  One of the bigger issues I ran up against was paginating the results returned from the server.  

There are a few gems and modules that I could have used to tie in the pagination however all of them seem to be overkill for what I need.  I simply need to build pagination on each request based off the current page we are on and the total pages from our search.

In rails I built a simple endpoint that returns the json array of the paginated results, the current page, and the total pages from our search. Now every time we query the endpoint we will rebuild the pagination. 

And here is the angular pagination. 

https://gist.github.com/joshualcoffee/9655849

Please feel free to leave comments if you see any improvements.

[k1ife-blog-blog]

will paginate

require 'will_paginate/view_helpers/action_view' module WillPaginate module ActionView def will_paginate(collection = nil, options = {}) options, collection = collection, nil if collection.is_a? Hash # Taken from original will_paginate code to handle if the helper is not passed a collection object. collection ||= infer_collection_from_controller options[:renderer] ||= BootstrapLinkRenderer super.try :html_safe end class BootstrapLinkRenderer < LinkRenderer protected def html_container(html) tag :div, tag(:ul, html), container_attributes end def page_number(page) tag :li, link(page, page, :rel => rel_value(page)), :class => ('active' if page == current_page) end def gap tag :li, link('…'.html_safe, '#'), :class => 'disabled' end def previous_or_next_page(page, text, classname) tag :li, link(text, page || '#'), :class => [(classname[0..3] if @options[:page_links]), (classname if @options[:page_links]), ('disabled' unless page)].join(' ') end end end end https://github.com/yrgoldteeth/bootstrap-will_paginate/blob/master/config/initializers/will_paginate.rb

[lucasallanamorim]

Paginação no Rails usando o will_paginate

Uma maneira fácil de se trabalhar com paginação no Ruby on Rails é utilizar o plugin will_paginate. Nesse breve artigo irei demonstrar como instalar e utilizar em sua aplicação. Primeiro instalaremos o plugin: gem install will_paginate Com o plugin instalado, podemos começar a configura-lo na aplicação. Para isso abra o arquivo environment.rb dentro do diretório config e adicione no final do arquivo a seguinte linha:

require "will_paginate"

Com isso, sua aplicação só irá subir se o plugin will_paginate estiver presente. Já no controlador devo usar o método paginate para efetuar a busca pelos registros no banco. No meu caso, tenho uma entidade chamada 'noticia' e no método 'index' do seu controlador, pelo padrão o rails faz uma busca por todos os registros no banco.

def index @noticias = Noticia.all respond_to do |format| format.html # index.html.erb format.xml { render : xml => @noticias } end

E no caso eu irei deixa-lo assim:

def index @noticias = Noticia.paginate :page => params[:page], : order => 'created_at DESC', :per_page => 10 respond_to do |format| format.html # index.html.erb format.xml { render : xml => @noticias } end end

Onde o ":order =>" irá definir a ordem de exibição dos registros. E o ":per_page =>" a quantidade de registros por página. E pra terminar, abra a view e adicione logo abaixo do término da tabela:

<%= will_paginate @noticias %>

[aboutrails-blog]

RailsCasts #51 will_paginate (revised)

The will_paginate episode has been revised: http://rh.gd/oBwjLg

[peterko-blog]

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