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Hackmamba profile image Demola Malomo
Demola Malomo for Hackmamba

Posted on • Originally published at fullstackwriter.dev

How to build a fullstack application with Go, Templ, and HTMX

#go #fullstack #htmx #xata

Go is a statically typed, compiled high-level programming language for building systems, command-line interfaces (CLI), and more. It is typically designed for use on the backend; however, there are times when you want to use the same language to build a full-stack application with a functional backend and a visual frontend.

In most cases, Go developers opt for frontend frameworks/libraries like React, Vue, Angular, etc., to build the frontend part of the application. This means they must learn JavaScript/TypeScript, framework-specific paradigms, and other frontend-related overheads.

In this guide, you’ll learn how to build a fullstack application with Go using Templ, HTMX, and Xata.

Technology Overview

Templ: is a templating engine that lets you build HTML with Go. It also lets you use Go syntax like if, switch, and for statements to build a robust frontend. You will use Templ to build reusable components and pages for the frontend.

HTMX: is a frontend library that lets you access modern browser features directly using HTML rather than JavaScript. You will use HTMX to process the form submission and perform other dynamic operations.

Xata: is a serverless database with analytics and free-text search support that makes a wide range of applications easy to build.

Prerequisites

To follow along with this tutorial, the following are needed:

Getting started

To get started, you need to install Templ binary. The binary generates Go code from a Templ file.

go install github.com/a-h/templ/cmd/templ@latest
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Create a directory.

mkdir go_fullstack && cd go_fullstack
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Next, initialize a Go module to manage project dependencies.

go mod init go-fullstack
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Finally, we proceed to install the required dependencies with:

go get github.com/gin-gonic/gin github.com/a-h/templ github.com/joho/godotenv
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github.com/gin-gonic/gin is a framework for building web applications.

github.com/a-h/templ is the Templ library used in the project.

github.com/joho/godotenv is a library for loading environment variables.

Structuring the application

To do this, create a cmd, internals, and views folder in our project directory.

cmd is for structuring the application entry point.

internals is for structuring API-related files.

views is for structuring frontend-related files.

Setup the database on Xata

Log into the Xata workspace and create a todo database. Inside the todo database, create a Todo table and add a description column of type String.

create project

Get the Database URL and set up the API Key

To get the database URL, click the Get code snippet button and copy the URL. Then click the API Key link, add a new key, save and copy the API key.


Setup environment variable

Create a .env file in the root directory and add the copied URL and API key.

XATA_DATABASE_URL= <REPLACE WITH THE COPIED DATABASE URL>
XATA_API_KEY=<REPLACE WITH THE COPIED API KEY>
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Build the application Frontend

To build the frontend, you’ll use Templ and HTMX to structure the application and add dynamism to a Todo application.

Create the application components

Inside the views folder, create a components/header.templ file and add the snippet below:

package components

templ Header() {
    <head>
        <script
            src="https://unpkg.com/htmx.org@1.9.10"
            integrity="sha384-D1Kt99CQMDuVetoL1lrYwg5t+9QdHe7NLX/SoJYkXDFfX37iInKRy5xLSi8nO7UC"
            crossorigin="anonymous"
        ></script>
        <script src="https://cdn.tailwindcss.com"></script>
        <meta charset="UTF-8" />
        <meta name="viewport" content="width=device-width, initial-scale=1.0" />
        <title>GO Fullstack</title>
    </head>
}
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The snippet creates a Header component and adds HTMX and TailwindCSS CDNs. TailwindCSS is a low-level framework for styling.

Next, create a components/footer.templ file to create the application footer and style using TailwindCSS classes.

package components

templ Footer() {
    <footer class="fixed p-1 bottom-0 bg-gray-100 w-full border-t">
    <div class="rounded-lg p-4 text-xs italic text-gray-700 text-center">
        &copy; Go Fullstack
    </div>
    </footer>
}
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Finally, create an index.templ file inside the same views folder and add the snippet below:

package views

import (
    "fmt"
    "go_fullstack/views/components"
)

type Todo struct {
    Id          string
    Description string
}

templ Index(todos []*Todo) {
    <!DOCTYPE html>
    <html lang="en">
        @components.Header()
        <body>
            <main class="min-h-screen w-full">
                <nav class="flex w-full border border-b-zinc-200 px-4 py-4">
                    <h3 class="text-base lg:text-lg font-medium text-center">
                        GO Fullstack app
                    </h3>
                </nav>
                <div class="mt-6 w-full flex justify-center items-center flex-col">
                    // FORM PROCESSING
                    <form
                        hx-post="/"
                        hx-trigger="submit"
                        hx-swap="none"
                        onsubmit="reloadPage()"
                        class="w-96"
                    >
                        <textarea
                            name="description"
                            cols="30"
                            rows="2"
                            class="w-full border rounded-lg mb-2 p-4"
                            placeholder="Input todo details"
                            required
                        ></textarea>
                        <button
                            class="py-1 px-4 w-full h-10 rounded-lg text-white bg-zinc-800"
                        >
                            Create
                        </button>
                    </form>
                    <section class="border-t border-t-zinc-200 mt-6 px-2 py-4 w-96">
                        // LOOP THROUGH THE TODOS
                        <ul id="todo-list">
                            for _, todo := range todos {
                                <li class="ml-4 ml-4 border p-2 rounded-lg mb-2" id={ fmt.Sprintf("%s", todo.Id) }>
                                    <p class="font-medium text-sm">Todo item { todo.Id }</p>
                                    <p class="text-sm text-zinc-500 mb-2">
                                        { todo.Description }
                                    </p>
                                    <div class="flex gap-4 items-center mt-2">
                                        <a
                                            href="#"
                                            class="flex items-center border py-1 px-2 rounded-lg"
                                        >
                                            <p class="text-sm">Edit</p>
                                        </a>
                                        <button
                                            hx-delete={ fmt.Sprintf("/%s", todo.Id) }
                                            hx-swap="delete"
                                            hx-target={ fmt.Sprintf("#%s", todo.Id) }
                                            class="flex items-center border py-1 px-2 rounded-lg hover:bg-red-300"
                                        >
                                            <p class="text-sm">Delete</p>
                                        </button>
                                    </div>
                                </li>
                            }
                        </ul>
                    </section>
                </div>
            </main>
        </body>
        @components.Footer()
    </html>
    <script>
        function reloadPage() {
                setTimeout(function() {
            window.location.reload();
        }, 2000);
        }
    </script>
}
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The snippet above does the following:

  • Imports the required dependencies
  • Creates a Todo struct to represent the response data coming from the backend
  • Creates an Index component that uses the Header and Footer components to structure the page. Then, it uses the HTMX attributes to process form submissions and deletion of todos by calling the respective endpoints / and /{todo.Id}

Generating Go files from the Templ files

Next, use the Templ binary you installed earlier to Generate Go codes from the views created above by running the command below in your terminal:

templ generate
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After you run this command, you’ll see new Go files generated for each view. You use generated file to render your frontend in next section.

Generated files

The generated files are not to be edited.

Putting it together and building the backend

With that done, you can use it to build the backend and render the required page.

Create the API models and helper function

To represent the application data, create a model.go file inside the internals folder and add the snippet below:

package internals

type Todo struct {
    Id          string `json:"id,omitempty"`
    Description string `json:"description,omitempty"`
}

type TodoRequest struct {
    Description string `json:"description,omitempty"`
}

type TodoResponse struct {
    Id string `json:"id,omitempty"`
}
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The snippet above creates a Todo, TodoRequest, and TodoResponse struct with the required properties to describe requests and response types.

Finally, create a helpers.go file with a reusable function to load environment variables.

package internals

import (
    "log"
    "os"
    "github.com/joho/godotenv"
)

func GetEnvVariable(key string) string {
    err := godotenv.Load()
    if err != nil {
        log.Fatal("Error loading .env file")
    }
    return os.Getenv(key)
}
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Create the application and API routes

Create a route.go file for configuring the API routes and add the snippet below:

package api

import "github.com/gin-gonic/gin"

type Config struct {
    Router *gin.Engine
}

func (app *Config) Routes() {
    //routes will come here
}
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The snippet above does the following:

  • Imports the required dependency
  • Creates a Config struct with a Router property to configure the application methods
  • Creates a Routes function that takes in the Config struct as a pointer

Create the API services

With that done, create a xata_service.go file for the application and update it by doing the following:

First, import the required dependencies and create a helper function:

package internals

import (
    "bytes"
    "encoding/json"
    "fmt"
    "net/http"
)

var xataAPIKey = GetEnvVariable("XATA_API_KEY")
var baseURL = GetEnvVariable("XATA_DATABASE_URL")

func createRequest(method, url string, bodyData *bytes.Buffer) (*http.Request, error) {
    var req *http.Request
    var err error'

    if method == "GET" || method == "DELETE" || bodyData == nil {
        req, err = http.NewRequest(method, url, nil)
    } else {
        req, err = http.NewRequest(method, url, bodyData)
    }

    if err != nil {
        return nil, err
    }

    req.Header.Add("Content-Type", "application/json")
    req.Header.Add("Authorization", fmt.Sprintf("Bearer %s", xataAPIKey))

    return req, nil
}
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The snippet above does the following:

  • Imports the required dependencies
  • Creates required environment variables
  • Creates a createRequest function that creates HTTP requests with the required headers

Lastly, add a createTodoService, deleteTodoService, and getAllTodosService methods to create, delete, and get the list of todos.

//imports goes here

func createRequest(method, url string, bodyData *bytes.Buffer) (*http.Request, error) {
    //createRequest code goes here
}

func (app *Config) createTodoService(newTodo *TodoRequest) (*TodoResponse, error) {
    createTodo := TodoResponse{}
    jsonData := Todo{
        Description: newTodo.Description,
    }

    bodyData := new(bytes.Buffer)
    json.NewEncoder(bodyData).Encode(jsonData)

    fullURL := fmt.Sprintf("%s:main/tables/Todo/data", baseURL)
    req, err := createRequest("POST", fullURL, bodyData)
    if err != nil {
        return nil, err
    }

    client := &http.Client{}
    resp, err := client.Do(req)
    if err != nil {
        return nil, err
    }

    defer resp.Body.Close()
    if err := json.NewDecoder(resp.Body).Decode(&createTodo); err != nil {
        return nil, err
    }

    return &createTodo, nil
}
func (app *Config) deleteTodoService(id string) (string, error) {
    fullURL := fmt.Sprintf("%s:main/tables/Todo/data/%s", baseURL, id)
    client := &http.Client{}
    req, err := createRequest("DELETE", fullURL, nil)
    if err != nil {
        return "", err
    }

    resp, err := client.Do(req)
    if err != nil {
        return "", err
    }
    defer resp.Body.Close()

    return id, nil
}

func (app *Config) getAllTodosService() ([]*Todo, error) {
    var todos []*Todo

    fullURL := fmt.Sprintf("%s:main/tables/Todo/query", baseURL)
    client := &http.Client{}
    req, err := createRequest("POST", fullURL, nil)
    if err != nil {
        return nil, err
    }

    resp, err := client.Do(req)
    if err != nil {
        return nil, err
    }

    defer resp.Body.Close()
    var response struct {
        Records []*Todo `json:"records"`
    }

    decoder := json.NewDecoder(resp.Body)
    if err := decoder.Decode(&response); err != nil {
        return nil, err
    }

    todos = response.Records
    return todos, nil
}
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Create the API handlers

With that done, you can use the services to create the API handlers. Create a handler.go file inside internals folder and add the snippet below:

package internals

import (
    "context"
    "fmt"
    "go_fullstack/views"
    "net/http"
    "time"
    "github.com/a-h/templ"
    "github.com/gin-gonic/gin"
)

const appTimeout = time.Second * 10

func render(ctx *gin.Context, status int, template templ.Component) error {
    ctx.Status(status)
    return template.Render(ctx.Request.Context(), ctx.Writer)
}

func (app *Config) indexPageHandler() gin.HandlerFunc {
    return func(ctx *gin.Context) {
        _, cancel := context.WithTimeout(context.Background(), appTimeout)
        defer cancel()

        todos, err := app.getAllTodosService()
        if err != nil {
            ctx.JSON(http.StatusBadRequest, err.Error())
            return
        }

        var viewsTodos []*views.Todo
        for _, todo := range todos {
            viewsTodo := &views.Todo{
                Id:          todo.Id,
                Description: todo.Description,
            }
            viewsTodos = append(viewsTodos, viewsTodo)
        }

        render(ctx, http.StatusOK, views.Index(viewsTodos))
    }
}

func (app *Config) createTodoHandler() gin.HandlerFunc {
    return func(ctx *gin.Context) {
        _, cancel := context.WithTimeout(context.Background(), appTimeout)
        description := ctx.PostForm("description")
        defer cancel()

        newTodo := TodoRequest{
            Description: description,
        }

        data, err := app.createTodoService(&newTodo)
        if err != nil {
            ctx.JSON(http.StatusBadRequest, err.Error())
            return
        }

        ctx.JSON(http.StatusCreated, data)
    }
}

func (app *Config) deleteTodoHandler() gin.HandlerFunc {
    return func(ctx *gin.Context) {
        _, cancel := context.WithTimeout(context.Background(), appTimeout)
        id := ctx.Param("id")
        defer cancel()

        data, err := app.deleteTodoService(id)
        if err != nil {
            ctx.JSON(http.StatusBadRequest, err.Error())
            return
        }

        ctx.JSON(http.StatusAccepted, fmt.Sprintf("Todo with ID: %s deleted successfully!!", data))
    }
}
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The snippet above does the following

  • Imports the required dependencies
  • Creates a render function that uses the Templ package to render matching template
  • Creates an indexPageHandler function that returns a Gin-gonic handler and takes in the Config struct as a pointer. Inside the returned handler, use the getAllTodosService service to get the list of todos and then render the appropriate page using the generated code from the views package (frontend)
  • Creates a createdTodoHandler and deleteProjectHandler functions that return a Gin-gonic handler and take in the Config struct as a pointer. Use the service created earlier to perform the corresponding action inside the returned handler

Update the API routes to use handlers

Update the routes.go file with the handlers as shown below:

package internals

import (
    "github.com/gin-gonic/gin"
)

type Config struct {
    Router *gin.Engine
}

func (app *Config) Routes() {
    //views
    app.Router.GET("/", app.indexPageHandler())

    //apis
    app.Router.POST("/", app.createTodoHandler())
    app.Router.DELETE("/:id", app.deleteTodoHandler())
}
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Putting it all together

Create the application entry point to use to serve the routes. To do this, create a main.go file inside the cmd folder and add the snippet below:

package main

import (
    "go_fullstack/internals"
    "github.com/gin-gonic/gin"
)

func main() {
    router := gin.Default()

    //initialize config
    app := internals.Config{Router: router}

    //routes
    app.Routes()

    router.Run(":8080")
}
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The snippet above does the following:

  • Imports the required dependencies
  • Creates a Gin router using the Default configuration
  • Initialize the Config struct by passing in the Router
  • Adds the route and run the application on port :8080

With that done, you can start a development server using the command below:

go run cmd/main.go
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The complete source code can be found on GitHub.

Conclusion

This post discusses how to build a fullstack application with Go, Templ, HTMX, and Xata. You can extend the application further to support viewing and editing todos.

These resources may also be helpful:

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