When we conduct moderated research, like user interviews or usability tests, for our clients, we encourage them to observe as many sessions as possible. We find when clients see us interview their users, and get real-time responses, they’re able to learn about the needs of their users in real-time and be more active participants in the process. One way we help clients feel engaged with the process during remote sessions is to establish a real-time communication backchannel that empowers clients to flag responses they’d like to dig into further and to share their ideas for follow-up questions.

There are several benefits to establishing a communication backchannel for moderated sessions:

• Everyone on the team, including both internal and client team members, can be actively involved throughout the data collection process rather than waiting to passively consume findings.
• Team members can identify follow-up questions in real-time which allows the moderator to incorporate those questions during the current session, rather than just considering them for future sessions.
• Subject matter experts can identify more detailed and specific follow-up questions that the moderator may not think to ask.
• Even though the whole team is engaged, a single moderator still maintains control over the conversation which creates a consistent experience for the participant.

If you’re interested in creating your own backchannel, here are some tips to make the process work smoothly:

• Use the chat tool that is already being used on the project. In most cases, we use a joint Slack workspace for the session backchannel but we’ve also used Microsoft Teams.
• Create a dedicated channel like #moderated-sessions. Conversation in this channel should be limited to backchannel discussions during sessions. This keeps the communication consolidated and makes it easier for the moderator to stay focused during the session.
• Keep communication limited. Channel participants should ask basic questions that are easy to consume quickly. Supplemental commentary and analysis should not take place in the dedicated channel.
• Use emoji responses. The moderator can add a quick thumbs up to indicate that they’ve seen a question.

Introducing backchannels for communication during remote moderated sessions has been a beneficial change to our research process. It not only provides an easy way for clients to stay engaged during the data collection process but also increases the moderator’s ability to focus on the most important topics and to ask the most useful follow-up questions.

In my last post, I covered what LiveView is at a high level. In this series, we’re going to dive deeper and implement a LiveView powered Markdown editor called Frampton. This series assumes you have some familiarity with Phoenix and Elixir, including having them set up locally. Check out Elizabeth’s three-part series on getting started with Phoenix for a refresher.

This series has a companion repository published on GitHub. Get started by cloning it down and switching to the starter branch. You can see the completed application on master. Our goal today is to make a Markdown editor, which allows a user to enter Markdown text on a page and see it rendered as HTML next to it in real-time. We’ll make use of LiveView for the interaction and the Earmark package for rendering Markdown. The starter branch provides some styles and installs LiveView.

Rendering Markdown

Let’s set aside the LiveView portion and start with our data structures and the functions that operate on them. To begin, a Post will have a body, which holds the rendered HTML string, and title. A string of markdown can be turned into HTML by calling Post.render(post, markdown). I think that just about covers it!

First, let’s define our struct in lib/frampton/post.ex:

Now the failing test (in test/frampton/post_test.exs):

Our render method will just be a wrapper around Earmark.as_html!/2 that puts the result into the body of the post. Add {:earmark, "~> 1.4.3"} to your deps in mix.exs, run mix deps.get and fill out render function:

Our test should now pass, and we can render posts! [Note: we’re using the as_html! method, which prints error messages instead of passing them back to the user. A smarter version of this would handle any errors and show them to the user. I leave that as an exercise for the reader…] Time to play around with this in an IEx prompt (run iex -S mix in your terminal):

Great! That’s exactly what we’d expect. You can find the final code for this in the render_post branch.

LiveView Editor

Now for the fun part: Editing this live!

First, we’ll need a route for the editor to live at: /editor sounds good to me. LiveViews can be rendered from a controller, or directly in the router. We don’t have any initial state, so let's go straight from a router.

First, let's put up a minimal test. In test/frampton_web/live/editor_live_test.exs:

This test doesn’t do much yet, but notice that it isn’t live view specific. Our first render is just the same as any other controller test we’d write. The page’s content is there right from the beginning, without the need to parse JavaScript or make API calls back to the server. Nice.

To make that test pass, add a route to lib/frampton_web/router.ex. First, we import the LiveView code, then we render our Editor:

Now place a minimal EditorLive module, in lib/frampton_web/live/editor_live.ex:

And we have a passing test suite! The ~L sigil designates that LiveView should track changes to the content inside. We could keep all of our markup in this render/1 method, but let’s break it out into its own template for demonstration purposes.

Move the contents of render into lib/frampton_web/templates/editor/show.html.leex, and replace EditorLive.render/1 with this one liner: def render(assigns), do: FramptonWeb.EditorView.render("show.html", assigns). And finally, make an EditorView module in lib/frampton_web/views/editor_view.ex:

Our test should now be passing, and we’ve got a nicely separated out template, view and “live” server. We can keep markup in the template, helper functions in the view, and reactive code on the server. Now let’s move forward to actually render some posts!

Handling User Input

We’ve got four tasks to accomplish before we are done:

1. Take markdown input from the textarea
2. Send that input to the LiveServer
3. Turn that raw markdown into HTML
4. Return the rendered HTML to the page.

Event binding

To start with, we need to annotate our textarea with an event binding. This tells the liveview.js framework to forward DOM events to the server, using our liveview channel. Open up lib/frampton_web/templates/editor/show.html.leex and annotate our textarea:

<textarea phx-keyup="render_post"></textarea>

This names the event (render_post) and sends it on each keyup. Let’s crack open our web inspector and look at the web socket traffic. Using Chrome, open the developer tools, navigate to the network tab and click WS. In development you’ll see two socket connections: one is Phoenix LiveReload, which polls your filesystem and reloads pages appropriately. The second one is our LiveView connection. If you let it sit for a while, you’ll see that it's emitting a “heartbeat” call. If your server is running, you’ll see that it responds with an “ok” message. This lets LiveView clients know when they've lost connection to the server and respond appropriately.

Now, type some text and watch as it sends down each keystroke. However, you’ll also notice that the server responds with a “phx_error” message and wipes out our entered text. That's because our server doesn’t know how to handle the event yet and is throwing an error. Let's fix that next.

Event handling

We’ll catch the event in our EditorLive module. The LiveView behavior defines a handle_event/3 callback that we need to implement. Open up lib/frampton_web/live/editor_live.ex and key in a basic implementation that lets us catch events:

The first argument is the name we gave to our event in the template, the second is the data from that event, and finally the socket we’re currently talking through. Give it a try, typing in a few characters. Look at your running server and you should see a stream of events that look something like this:

There’s our keystrokes! Next, let’s pull out that value and use it to render HTML.

Rendering Markdown

Lets adjust our handle_event to pattern match out the value of the textarea:

def handle_event("render_post", %{"value" => raw}, socket) do

Now that we’ve got the raw markdown string, turning it into HTML is easy thanks to the work we did earlier in our Post module. Fill out the body of the function like this:

If you type into the textarea you should see output that looks something like this:

Perfect! Lastly, it’s time to send that rendered html back to the page.

Returning HTML to the page

In a LiveView template, we can identify bits of dynamic data that will change over time. When they change, LiveView will compare what has changed and send over a diff. In our case, the dynamic content is the post body.

Open up show.html.leex again and modify it like so:

Refresh the page and see:

Whoops!

The @post variable will only be available after we put it into the socket’s assigns. Let’s initialize it with a blank post. Open editor_live.ex and modify our mount/3 function:

In the future, we could retrieve this from some kind of storage, but for now, let's just create a new one each time the page refreshes. Finally, we need to update the Post struct with user input. Update our event handler like this:

Let's load up http://localhost:4000/editor and see it in action.

Nope, that's not quite right! Phoenix won’t render this as HTML because it’s unsafe user input. We can get around this (very good and useful) security feature by wrapping our content in a raw/1 call. We don’t have a database and user processes are isolated from each other by Elixir. The worst thing a malicious user could do would be crash their own session, which doesn’t bother me one bit.

Check the edit_posts branch for the final version.

Conclusion

That’s a good place to stop for today. We’ve accomplished a lot! We’ve got a dynamically rendering editor that takes user input, processes it and updates the page. And we haven’t written any JavaScript, which means we don’t have to maintain or update any JavaScript. Our server code is built on the rock-solid foundation of the BEAM virtual machine, giving us a great deal of confidence in its reliability and resilience.

In the next post, we’ll tackle making a shared editor, allowing multiple users to edit the same post. This project will highlight Elixir’s concurrency capabilities and demonstrate how LiveView builds on them to enable some incredible user experiences.

Viget Explorations have always been the result of our shared curiosities. They’re usually a spontaneous outcome of team downtime and a shared problem we’ve experienced. We use our Explorations to pursue our diverse interests and contribute to the conversations about building a better digital world.

As the COVID-19 crisis emerged, we were certainly experiencing a shared problem. As a way to keep busy and manage our anxieties, a small team came together to dive into how technology has helped, and, unfortunately, hindered the community response to the current pandemic.

We started by researching the challenges we saw: information overload, a lack of clarity, individual responsibility, and change. Then we brainstormed possible technical solutions that could further improve how communities respond to a pandemic. Click here to see our Exploration on some possible ways to take the panic out of pandemics.

While we aren’t currently pursuing the solutions outlined in the Exploration, we’d love to hear what you think about these approaches, as well as any ideas you have for how technology can help address the outlined challenges.

Please note, this Exploration doesn’t provide medical information. Visit the Center for Disease Control’s website for current information and COVID-19, its symptoms, and treatments.

At Viget, we’re adjusting to this crisis for the safety of our clients, our staff, and our communities. If you’d like to hear from Viget's co-founder, Brian Williams, you can read his article on our response to the situation.

When we conduct moderated research, like user interviews or usability tests, for our clients, we encourage them to observe as many sessions as possible. We find when clients see us interview their users, and get real-time responses, they’re able to learn about the needs of their users in real-time and be more active participants in the process. One way we help clients feel engaged with the process during remote sessions is to establish a real-time communication backchannel that empowers clients to flag responses they’d like to dig into further and to share their ideas for follow-up questions.

There are several benefits to establishing a communication backchannel for moderated sessions:

• Everyone on the team, including both internal and client team members, can be actively involved throughout the data collection process rather than waiting to passively consume findings.
• Team members can identify follow-up questions in real-time which allows the moderator to incorporate those questions during the current session, rather than just considering them for future sessions.
• Subject matter experts can identify more detailed and specific follow-up questions that the moderator may not think to ask.
• Even though the whole team is engaged, a single moderator still maintains control over the conversation which creates a consistent experience for the participant.

If you’re interested in creating your own backchannel, here are some tips to make the process work smoothly:

• Use the chat tool that is already being used on the project. In most cases, we use a joint Slack workspace for the session backchannel but we’ve also used Microsoft Teams.
• Create a dedicated channel like #moderated-sessions. Conversation in this channel should be limited to backchannel discussions during sessions. This keeps the communication consolidated and makes it easier for the moderator to stay focused during the session.
• Keep communication limited. Channel participants should ask basic questions that are easy to consume quickly. Supplemental commentary and analysis should not take place in the dedicated channel.
• Use emoji responses. The moderator can add a quick thumbs up to indicate that they’ve seen a question.

Introducing backchannels for communication during remote moderated sessions has been a beneficial change to our research process. It not only provides an easy way for clients to stay engaged during the data collection process but also increases the moderator’s ability to focus on the most important topics and to ask the most useful follow-up questions.

In my last post, I covered what LiveView is at a high level. In this series, we’re going to dive deeper and implement a LiveView powered Markdown editor called Frampton. This series assumes you have some familiarity with Phoenix and Elixir, including having them set up locally. Check out Elizabeth’s three-part series on getting started with Phoenix for a refresher.

This series has a companion repository published on GitHub. Get started by cloning it down and switching to the starter branch. You can see the completed application on master. Our goal today is to make a Markdown editor, which allows a user to enter Markdown text on a page and see it rendered as HTML next to it in real-time. We’ll make use of LiveView for the interaction and the Earmark package for rendering Markdown. The starter branch provides some styles and installs LiveView.

Rendering Markdown

Let’s set aside the LiveView portion and start with our data structures and the functions that operate on them. To begin, a Post will have a body, which holds the rendered HTML string, and title. A string of markdown can be turned into HTML by calling Post.render(post, markdown). I think that just about covers it!

First, let’s define our struct in lib/frampton/post.ex:

Now the failing test (in test/frampton/post_test.exs):

Our render method will just be a wrapper around Earmark.as_html!/2 that puts the result into the body of the post. Add {:earmark, "~> 1.4.3"} to your deps in mix.exs, run mix deps.get and fill out render function:

Our test should now pass, and we can render posts! [Note: we’re using the as_html! method, which prints error messages instead of passing them back to the user. A smarter version of this would handle any errors and show them to the user. I leave that as an exercise for the reader…] Time to play around with this in an IEx prompt (run iex -S mix in your terminal):

Great! That’s exactly what we’d expect. You can find the final code for this in the render_post branch.

LiveView Editor

Now for the fun part: Editing this live!

First, we’ll need a route for the editor to live at: /editor sounds good to me. LiveViews can be rendered from a controller, or directly in the router. We don’t have any initial state, so let's go straight from a router.

First, let's put up a minimal test. In test/frampton_web/live/editor_live_test.exs:

This test doesn’t do much yet, but notice that it isn’t live view specific. Our first render is just the same as any other controller test we’d write. The page’s content is there right from the beginning, without the need to parse JavaScript or make API calls back to the server. Nice.

To make that test pass, add a route to lib/frampton_web/router.ex. First, we import the LiveView code, then we render our Editor:

Now place a minimal EditorLive module, in lib/frampton_web/live/editor_live.ex:

And we have a passing test suite! The ~L sigil designates that LiveView should track changes to the content inside. We could keep all of our markup in this render/1 method, but let’s break it out into its own template for demonstration purposes.

Move the contents of render into lib/frampton_web/templates/editor/show.html.leex, and replace EditorLive.render/1 with this one liner: def render(assigns), do: FramptonWeb.EditorView.render("show.html", assigns). And finally, make an EditorView module in lib/frampton_web/views/editor_view.ex:

Our test should now be passing, and we’ve got a nicely separated out template, view and “live” server. We can keep markup in the template, helper functions in the view, and reactive code on the server. Now let’s move forward to actually render some posts!

Handling User Input

We’ve got four tasks to accomplish before we are done:

1. Take markdown input from the textarea
2. Send that input to the LiveServer
3. Turn that raw markdown into HTML
4. Return the rendered HTML to the page.

Event binding

To start with, we need to annotate our textarea with an event binding. This tells the liveview.js framework to forward DOM events to the server, using our liveview channel. Open up lib/frampton_web/templates/editor/show.html.leex and annotate our textarea:

<textarea phx-keyup="render_post"></textarea>

This names the event (render_post) and sends it on each keyup. Let’s crack open our web inspector and look at the web socket traffic. Using Chrome, open the developer tools, navigate to the network tab and click WS. In development you’ll see two socket connections: one is Phoenix LiveReload, which polls your filesystem and reloads pages appropriately. The second one is our LiveView connection. If you let it sit for a while, you’ll see that it's emitting a “heartbeat” call. If your server is running, you’ll see that it responds with an “ok” message. This lets LiveView clients know when they've lost connection to the server and respond appropriately.

Now, type some text and watch as it sends down each keystroke. However, you’ll also notice that the server responds with a “phx_error” message and wipes out our entered text. That's because our server doesn’t know how to handle the event yet and is throwing an error. Let's fix that next.

Event handling

We’ll catch the event in our EditorLive module. The LiveView behavior defines a handle_event/3 callback that we need to implement. Open up lib/frampton_web/live/editor_live.ex and key in a basic implementation that lets us catch events:

The first argument is the name we gave to our event in the template, the second is the data from that event, and finally the socket we’re currently talking through. Give it a try, typing in a few characters. Look at your running server and you should see a stream of events that look something like this:

There’s our keystrokes! Next, let’s pull out that value and use it to render HTML.

Rendering Markdown

Lets adjust our handle_event to pattern match out the value of the textarea:

def handle_event("render_post", %{"value" => raw}, socket) do

Now that we’ve got the raw markdown string, turning it into HTML is easy thanks to the work we did earlier in our Post module. Fill out the body of the function like this:

If you type into the textarea you should see output that looks something like this:

Perfect! Lastly, it’s time to send that rendered html back to the page.

Returning HTML to the page

In a LiveView template, we can identify bits of dynamic data that will change over time. When they change, LiveView will compare what has changed and send over a diff. In our case, the dynamic content is the post body.

Open up show.html.leex again and modify it like so:

Refresh the page and see:

Whoops!

The @post variable will only be available after we put it into the socket’s assigns. Let’s initialize it with a blank post. Open editor_live.ex and modify our mount/3 function:

In the future, we could retrieve this from some kind of storage, but for now, let's just create a new one each time the page refreshes. Finally, we need to update the Post struct with user input. Update our event handler like this:

Let's load up http://localhost:4000/editor and see it in action.

Nope, that's not quite right! Phoenix won’t render this as HTML because it’s unsafe user input. We can get around this (very good and useful) security feature by wrapping our content in a raw/1 call. We don’t have a database and user processes are isolated from each other by Elixir. The worst thing a malicious user could do would be crash their own session, which doesn’t bother me one bit.

Check the edit_posts branch for the final version.

Conclusion

That’s a good place to stop for today. We’ve accomplished a lot! We’ve got a dynamically rendering editor that takes user input, processes it and updates the page. And we haven’t written any JavaScript, which means we don’t have to maintain or update any JavaScript. Our server code is built on the rock-solid foundation of the BEAM virtual machine, giving us a great deal of confidence in its reliability and resilience.

In the next post, we’ll tackle making a shared editor, allowing multiple users to edit the same post. This project will highlight Elixir’s concurrency capabilities and demonstrate how LiveView builds on them to enable some incredible user experiences.

Viget Explorations have always been the result of our shared curiosities. They’re usually a spontaneous outcome of team downtime and a shared problem we’ve experienced. We use our Explorations to pursue our diverse interests and contribute to the conversations about building a better digital world.

As the COVID-19 crisis emerged, we were certainly experiencing a shared problem. As a way to keep busy and manage our anxieties, a small team came together to dive into how technology has helped, and, unfortunately, hindered the community response to the current pandemic.

We started by researching the challenges we saw: information overload, a lack of clarity, individual responsibility, and change. Then we brainstormed possible technical solutions that could further improve how communities respond to a pandemic. Click here to see our Exploration on some possible ways to take the panic out of pandemics.

While we aren’t currently pursuing the solutions outlined in the Exploration, we’d love to hear what you think about these approaches, as well as any ideas you have for how technology can help address the outlined challenges.

Please note, this Exploration doesn’t provide medical information. Visit the Center for Disease Control’s website for current information and COVID-19, its symptoms, and treatments.

At Viget, we’re adjusting to this crisis for the safety of our clients, our staff, and our communities. If you’d like to hear from Viget's co-founder, Brian Williams, you can read his article on our response to the situation.