File Uploads with HTMX and Golang

Ofcourse you have already heard about the awesomeness of HTMX (you haven’t? well, good thing you’re here ?)

Today, we will be combining the simplicity of HTMX with the power of Golang to upload files to our server. Yeah, we are going to be building another exciting web feature with HTMX and Go.

By the way, if you really want a practical project-based guide on building fullstack apps with HTMX, check out my HTMX + Go: Build Fullstack Applications with Golang and HTMX course [Discount Included].

So, let’s begin.

Setting Up the Go Project

The first step is to setup a simple Go project. We can do that by creating a folder, going into it and initialising it as a Go project using the commands below:

mkdir go-htmx-file-uploads cd go-htmx-file-uploads go mod init go-htmx-file-uploads

Once we have the project initialized, let’s now install some dependencies we will be requiring within our project.

This will be a simple server that will contain a single page with our upload form and also an endpoint that will be used to upload the file.

For routing, we will be using the Gorilla Mux routing library, but feel free to use any routing solution of your choice. We will also be using Google’s UUID library for Go to generate random names for our files when we upload them. This is a personal preference as you can generate file names in different ways.

Install these two with the commands below:

Gorillla Mux

go get -u github.com/gorilla/mux

Google UUID

go get github.com/google/uuid

With these two installed, our project is fully set up, and we can move to the next step.

Creating our Templates

We will be creating two HTML templates for this little project.

The first template will be an HTML fragment that simply takes a slice of string messages that we can send from the server to the client.

This fragment will take this slice of messages and loop through it to create an HTML list to be returned to the client (remember how HTMX works with Hypermedia APIs, pretty cool huh ?).

So, let’s create that first.

At the root of the Go project, first create a templates folder inside which we will be storing all our templates.

Next, create a file messages.html inside the templates folder and add the following code to it:

{{define "messages"}} 
 {{range .}} 
{{ . }}
 {{end}} 
 {{end}}

This defines a messages template and loops through the incoming slice of string messages to form an HTML list.

For our next template, we will be creating the file upload page itself.

Inside the templates folder, create a new file upload.html and paste in the code below:

{{define "upload"}}         
  
 
 
Upload File
 
 
 
 Select Image  
 Upload 
 
 
   {{end}}

Perfect!

Now let’s go through the code in this file.

First, we have defined the template with the name upload, this is the name we will use to reference it later in our route handlers.

We then have some boilerplate HTML code in the head section, but I have included two important libraries here (well, just one is really important, the other is just for CSS vibes).

The HTMX library has been included with the