---
title: Realtime partial page updates with Turbo Streams
slug: realtime-partial-page-updates-with-turbo-streams
published_at: 2021-09-08 13:00:27 +0000
updated_at: 2026-03-04 20:13:56 +0000
summary: 
description: In this episode, you'll see how to setup and install turbo-rails to create partial page updates with Turbo streams in your Ruby on Rails applications. We'll broadcast updates to blog posts, and broadcast appends to our list of comments. #rails #rubyonrails
tags: [cjav_dev, web development tutorials, web development for beginners, vim, ruby, rails, javascript, turbo, turbo-rails, turbo streams, ruby on rails tutorial, ruby on rails]
views: 9404
author: CJ Avilla
url: https://www.cjav.dev/videos/realtime-partial-page-updates-with-turbo-streams
youtube_url: https://www.youtube.com/watch?v=ZB4YnzxMxkE
youtube_id: ZB4YnzxMxkE
embed_url: https://www.youtube.com/embed/ZB4YnzxMxkE
thumbnail_url: https://i.ytimg.com/vi/ZB4YnzxMxkE/hqdefault.jpg
type: video
---

# Realtime partial page updates with Turbo Streams

*Published: September 08, 2021*
*Views: 9404*

## Watch

[Watch on YouTube](https://www.youtube.com/watch?v=ZB4YnzxMxkE)

[![Realtime partial page updates with Turbo Streams](https://i.ytimg.com/vi/ZB4YnzxMxkE/hqdefault.jpg)](https://www.youtube.com/watch?v=ZB4YnzxMxkE)

## Description

In this episode, you'll see how to setup and install turbo-rails to create partial page updates with Turbo streams in your Ruby on Rails applications. We'll broadcast updates to blog posts, and broadcast appends to our list of comments.
#rails #rubyonrails

## Transcript

hey what's up welcome back in this episode you'll learn all about turbo streams so this is uh turbo it is a tool that was built by uh the rails team for using hay and this is sort of an extension of turbo links which was like this older technology which would sort of render things and swap out parts of the dom instead of rendering the entire dom and so turbo turbo links is basically like now going to be all inside of turbo rails and so turbo rails exposes a couple different things so you've got turbo drive turbo frames and turbos streams and these are all sort of separate and so what i wanted to do today was improve our blog application and use turbo streams to partially update parts of the page uh over a websocket connection and this is super cool very fun stuff um and so there's a bit of installation here that we'll need to to do uh it does use npm so there's like a javascript component of this so we will need to actually like import some stuff to get this working uh on the front end and also on the server um so at a high level we're going to try to do is make it so that when we update one of our blog posts it will automatically update uh in the browser so let's go over to our rails application so we've got this blog here that we've been working on um if you haven't heard if you haven't been following along there is uh there are several episodes on this channel where we go from zero to one basically with all of this blog stuff and so the first thing we need to do according to the instructions here is add the turbo rails gen so we'll say bundle add and then we'll say turbo rails that'll install the turbo rails gem and then we want to say rails turbo colon install and we'll see what this does this gives us a couple different files here so we're going to say rails turbo install so we're going to run this now because i didn't think this was actually modifying anything i think just the the turbo install is also doing the redis bit so right here we're all we are going to use redis server as our backing uh store um okay so it did actually modify uh it modified our gem file so that's cool um all right the next step is we actually want to go to application.js and uh import this turbo rails thing so go to application application js and then i don't know somewhere here i'll just import from at hotwired slash turbo dash rails and then we now that we've got all that stuff installed we can run our bin webpack dev server so that's going to compile all of our front-end stuff and get our front-end web packing all right then let's split this vertically and we'll also run rails s from this same tab here real server so we've got our webpack stuff happening we've got our rail server up and running and now we we can go talk about the actual implementation here so there's actually a bunch of different tools there's a frames helper a stream helper and a tag builder and this broadcastable concern so when i was first checking out turbo i i thought incorrectly i thought that you needed turbo frames to work with turbo streams turns out that's not the case at all you can use these turbo streams independent of turbo frames and by defining a stream you're sort of just going to listen for changes on the front end or you kind of like hook up a stream where the front end can receive web socket notifications and then those websocket notifications will target specific dom elements by id so you don't actually need frames you don't need anything else you just need to have like the stream set up so we'll take a look at that so if we go into like our um our post show so we have this show page where we're going to show like the title and description in fact if we pull this up and go to like posts slash 11 here so at the very top here we have the title of the post and the description the actual content of the post right and right now that's that's what that's what lives here in this part of the show view now one thing that i have seen is really common is breaking out all of the um breaking out sort of the the view pieces the template pieces that are specific to instance of of objects into partials so we've already got a couple different partials here we've got our likes button partial the comments form we've got a comment partial but we don't have a post partial yet so let's create a brand new partial here called underscore post.html.erb and this postpartial will just be this html here that shows the title and description okay and then we're going to come back over here we're going to say render at post and that should render the post partial so if we refresh our page nothing should have changed and that's correct so this this is like part one is sort of getting um getting each of your pieces into partials this is i think this is just a best practice too you don't necessarily need to do this the next thing i'm going to do is add a div with the id equal to the dom id of at post so what is this actually doing so we're wrapping up our post partial so this bit here we're going to wrap that in a new div so if we refresh the page here okay so now the the content for our post partial is wrapped in a div and you'll see this post underscore 11 that is the string value that was returned from dom i underscore id for app post so this dom id is going to give us a target an id that we can target on the front end so that we can do things to this dom id with turbo streams okay so all that we've done so far is just modify and set up our html so that it has this dom id wrapping up the partial from here the next thing we want to do is say turbo stream from at post and this means like we want to like listen for any updates that are happening to app post as like a turbo stream right here so if i refresh the page you'll see this like turbo cable stream source and then it has a channel and it has like a bunch of stuff here so this tag this turbo cable stream source tag is going to use a little bit of javascript on the front end and is going to listen for things that are being published over the websocket so um if we look back at this turbo rails gem we see this streams helper and inside of the streams helper this is a this is like where we have um our turbostream tags so turbo stream from this is where this method comes in and then we can pass in a bunch of streamables i actually don't know what constitutes a streamable but i in my experience this is just a bunch of like active record instances activerecord objects and then the attributes here allows you to specify like sub parts of those those models so in our case our streamable is just app post so we've got turbo stream from app post now what we're going to do is in the rails console so if we go into log here rails console is from the rails console we're going to modify the post we're going to modify the post and then we're going to broadcast and update and so broadcast is a tool is another part of turbo so that is inside of this turbo broadcastable so the broadcastable module is already mixed into active record active record models so we don't actually need to like do anything fancy to add this into our model but the turbo this broadcastable concern gives us a bunch of methods that we can call on the activerecord model and that will just publish updates over that websocket so let's take a look at what that looks like so we've got our blog post here testing with some comments so we're going to say p is post dot find 11 and so this is the the post that we're looking at in the browser i'm actually going to make this so on the right hand side we see the browser on the left hand side we see rails console and so we're going to say p dot title is equal to like modified in rails console okay so we are updating the post here directly so i've updated the title in memory and i'm going to say p dot save bang that's going to save it in the database now if i was to refresh this page i would see that the title has changed to modified in rails console but what i want to do instead is i want to say p dot broadcast update and i believe this should update the ui over here so if we hit enter it did not okay oh undefined method title for nil class ah okay okay so this is interesting this is interesting so when we say broadcast update it's trying to render that post html erb template that we created earlier and now it's saying undefined method title for nil class so let's go take a look at that partial and in this partial you'll notice that we're still using the at post instance variable instead of using the instance variable we want to we want to use the local variable and assume that we're being passed in that local variable so let's reload and try this again p equals post find 11 p dot broadcast update okay boom did you see it update over here we didn't actually refresh the browser but it's updating in real time so on the left we've got rendered posts post html and then we see this broadcasting to blah blah blah this giant html block so this turbo stream this turbostream tag here this is where the magic is actually happening so this is being sent over the websocket to our client and our client is receiving this websocket notification and it's deserializing this and it's seeing like okay the action that we want to do is update there's a few different actions you can do like update replace append pre-pen so you can there's a few different things you can do in this case we wanted to do is update so that we're modifying we're just like updating this partial this sort of partial part of the page and you can see here the target is post underscore 11. so it knew that the id of the dom element in the browser that we wanted to target was this uh was this dom element all right next inside of the html we see a template tag template tag that is like a really common feature when you're working with like swapping out client-side code and instead inside of the template tag is where we actually have the content of that post partial so when we rendered this post partial given p this is the content that came out so you can see the top the title says modified in rails console so if again we were to say like peta title is equal to testing again p dot safe bang p dot broadcast update now right when i hit enter we're looking right here we want to see this modified in rails console change so i'm going to hit enter boom testing again you can see that updated over here without having to refresh now where this becomes really interesting is when we have a bunch of different browser tabs open potentially right so we've got let's say we've got two here now now we're going to say p dot title is another update to both browsers p dot save bang p dot broadcast update boom now they both updated so you're able to sort of like push out updates across all the different browsers that are listening for streams um or for these turbo streams to come in so that's really a really cool way to automatically sort of push updates to the browser so this is this is an example of the update turbo stream um and in practice here what we might do is actually go into the post model and say like um we can we can set up a hook that says after we save this post let's broadcast an update so that this always happens so there's a bunch of uh active record hooks that we can use so we can say after update commit you want to broadcast update now what this should do is make it so that when we reload the browser and just save the object so now if we say like p is post.find 11 p dot title is test123 p dot save bang now when we save it that should cause an update to fire and that will update the browser so now we are updating we're using those active record callbacks to automatically update the browser so you could say like when we first create a post or update a post or whatever we want it to automatically broadcast certain updates so this is the basics of turbo streams the next step though that you might be wondering is like what happens if you are adding to a list so in the comments example right like as we add comments we want those to probably show up automatically so let's take a look at that now so the next version here that we want to play around with is is comments so if we jump out of this and we want to take a look at the com or let's see the post show again okay now inside of the comments um the comments section where we're rendering out the comments inside of the post show under here the first thing we need again is some element that we can target with our stream update similar to how we inserted the dom id here we want to have some sort of dom id that we can target here so i'm just going to make another div and in this case i'm just going to call or set the id of the div to comments and then i'm going to wrap all of the comments that are being rendered out by the comments partial inside of this div with id comments the next thing we want to do is add another turbo stream from so turbo stream from this time we're going to say at post because we do want to listen to updates for the post but in this case we want to target specifically the comments so if there is an update to a specific comment we want to um yeah be able to pipe that in here so what we can do now is go into the rails console again so we'll refresh this page and what we want to do is be able to create a new comment and have that appear in our list of comments so let's see what this looks like so if i say c equals comment dot create or post id 11 and user id 9 and content is testing from console okay so that gave us a new comment so we have c and we can say c dot broadcast and again there's going to be let's actually jump into c so we're going to cd into c i'm using um pry rails the pry rails gem here so i can just like change directory into a specific object now i can do ls and that shows me all of the methods on here and so one thing that i'm looking for is broadcast here's all the broadcastable methods so we've got broadcast in action append append later before et cetera et cetera et cetera so what we i think we want to do is we want to prepend to we want to broadcast a prepend to and then we're going to specify that we want to prepend it to the posts comments so here we're going to say we're going to say c dot broadcast prepend 2 and then we have to pass in the post object because recall that like in as part of our turbo stream from we're listening on the post for updates about comments so here we're going to say c.post that'll give us the instance of the post and then we can say comments here and i believe this should update or prepend to our comments so let's hit enter ah we've got an undefined method likes for nil class ah this is perfect okay so if we go into the comments or the comment partial here so we have a comments underscore comment.html.erb inside of this partial we are rendering a like button and that like button so likes button partial the likes button partial is accessing current user so right now when we are pushing turbo stream updates over websockets to all browsers it's possible that each browser window that's opening that's listening for updates has a different current user and so when we are trying to decide whether or not a current user has liked a specific post like in order to render this like button that is a um a user specific or user aware sort of feature and so because we are accessing current user here it doesn't know how to look up the current user because when we're pushing from the server there isn't really the context of a session we don't have a logged in user and so one way that you can get around this is by just making sure that there is a current user um and then otherwise just setting like to nil so we could say like uh the like is equal to blah blah blah if current user or if like current user is not nil and what this will do is we'll just assume that we're only going to use this partial when we have a brand new comment and so it won't matter whether or not the the customer has actually liked it or the user has liked it so let's try this again so we'll say reload and then c is comment dot last c dot broadcast prepend to see that post okay testing from console right there boom so we added a new comment so let's let's add another comment here c equals comment dot create testing from console again okay c dot uh broadcast prepend two so in this case we're not updating the comment right we're pre-pending to a list of comments so uh we're we're saying prepend to c dot post comments and so again this is going to show up here right in at the top of our comments so we hit enter now we have another another update here right if we wanted to show up at the very bottom we could say append 2 instead of prepend append to now it's showing up at the bottom the other thing that's weird is like you could keep broadcasting and even though these are not different comments they're the same comment we just keep broadcasting updates and so that's changing our our ui but it is not actually changing the database so if we were to refresh this page right we've got this testing from console again four times right now and if we refresh the page we will only see it at the top because this is only like this is the most recent comment so what we can do now is similar to adding that hook to post dot rb right remember we did this after update commit hook we can go to the comment and do an after create commit we can say broadcast prepend to post comments and we can save that and now when we reload this if we create a new comment it should automatically broadcast okay so let's say this comment is added from the terminal boom this comment is added from the terminal it's showing up here on the on the left that's super fancy and fun but watch this right so in the last episode recall that we set up our rails conductor or we set up inbound emails so that we could automatically add replies to comments so if we see like what is like this comment is comment 48 um so we can go into our to send a new inbound email from a user to comment 48 this is super cool because uh this comment is sent via email and so suppose you have again multiple browsers open or multiple different users are watching this page right and we have this comment is being sent via email and now we can say deliver inbound email and the you can see the comment is being sent via email is being appended here now this is actually not where it should be right like this should be appended as um as a reply so if we were to refresh this page it should show up as a reply down here so we have not actually like set it up so that you can that you can automatically render a reply i'll leave that as an exercise for you to go figure out and yeah so this is this is a super fun super fun little tool this is using turbo streams again and we are using some of the broadcast methods that are built into active record there's only a handful so you could really kind of go through and experiment with which ones you think make most sense it kind of reminds me a little bit of jquery too where you could find an element and then say pre-pen to append to or update or even replace so i did run into a little bug with replace it was actually replacing the entire dom node including the the div that had the target id so if you tried to update it a second time it wouldn't work because that was no longer in the dom so yeah hopefully this is useful and interesting i'm gonna actually uh implement tic-tac-toe in the next episode with streams again so that should be pretty fun thanks so much for watching and we'll see in the next one cheers [Music]

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