---
title: "Recent search history with Kredis"
author: "Yaroslav Shmarov"
date: "2023-02-19"
canonical_url: "https://blog.superails.com/kredis-resent-searches"
markdown_url: "https://blog.superails.com/kredis-resent-searches.md"
description: "Why use Redis? Hitting kredis is much cheaper than hitting a relational database. By storing high-frequency data on Redis we save resources. Wtf Kredis?"
tags: ["ruby-on-rails","redis","kredis"]
license: "GNU AGPL v3. Credit Yaroslav Shmarov and link the canonical URL."
---

# Recent search history with Kredis

**Why use Redis?** Hitting kredis is much cheaper than hitting a relational database. By storing high-frequency data on Redis we save resources.

**Wtf Kredis?** Kredis makes using Redis easier in Rails, and most importantly helps to associate Redis object with Rails Models.

Previously I wrote about ["Recently visited pages with Kredis"](https://blog.superails.com/kredis-recently-visited-pages){:target="blank"}

"**Recent search history**" is a very similar feature in terms of implementation.

Feature description:
- whenever a user submits a search form, the search query is saved in redis
- display the users last 5 search queries

**Prerequisites**:
- scaffold `Posts title:string`
- Authentication, `current_user`

**Implementation**:

First, associate a Redis entity of `kredis_unique_list` with the `user.rb` model:

```ruby
# app/models/user.rb
class User < ApplicationRecord
  kredis_unique_list :recent_searches, limit: 5
end
```

Add a search form:

```ruby
# app/views/posts/index.html.erb
<%= form_with url: posts_path do |form| %>
  <%= form.text_field :query %>
  <%= form.submit %>
<% end %>
```

When there search form is submitted, save the search params to `current_user.recent_searches`. `prepend` will add it at the top of the list:

```ruby
# app/controllers/posts_controller.rb
def index
  @posts = if params[:query].present?
            Post.where(name: params[:query])
            current_user.recent_searches.prepend(params[:query]) if params[:query].present?
           else
             Post.all
           end
end
```

Display a list of clickable recent searches:

```ruby
# app/views/users/_recently_searches.html.erb
<% current_user.recent_searches.elements.each do |query| %>
  <%= link_to query, posts_path(query:) %>
<% end %>
```

That's it!