Free Rails 7 #113 Kredis Live counter, HTTP vs Websocket Turbo Broadcasts

22/02/2023 (over 1 year ago)
kredis hotwire turbo actioncable live update redis live counter websockets

In the two previous episodes we use Kredis to store website visitors and users online. Let's dive deeper into what Kredis is and other ways we can use it!

Redis is now baked into Rails by default.
Kredis let's you easily save and retrieve data from Redis.
Killer feature of Kredis - reference ActiveRecord objects with Redis attributes.
For example - sstore User preferences in Redis, not Postgresql.
There are a lot of usecases for Kredis, and in this video I explore just a few.

In THIS episode we will build a counter with a PLUS and MINUS button.
When clicked, the two buttons will be able to increase or decrease the counter respectively.
We will also use Turbo Streams to update the counter without having to refresh the page.
We will compare HTTP turbo streams that send updates only in the window where the action happened, with turbo stream broadcasts, that send updates to ALL the clients that have a page open.

Episode source code: https://github.com/corsego/113-kredis-counter/commit/7819719780b7bd46770b8d1cafc156674fa85df2
Blogpost - kredis overview: https://blog.corsego.com/gem-kredis-intro

0:00 Redis in Rails 7
1:09 install Kredis
1:39 use Kredis from Rails console, Kredis list (array)
2:30 Kredis unique list (array)
3:26 Kredis counter (integer)
3:54 display Kredis counter in Rails view
5:58 button to increment counter
7:16 button to decrement counter
8:05 refresh counter with HTTP Turbo Streams
11:20 push live counter updates with Turbo Stream Broadcasts that use ActionCable and Websockets
13:30 Works! Counter gets updated in all browser windows!


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