📖 Go Fiber by Examples: Working with middlewares and boilerplates

Introduction

Hey, DEV friends! 👋

So, we've already got a good understanding of the key features and the inner workings of the Fiber web framework. Now, it's the turn of additional tools and packages that can greatly improve our productivity as Go programmers.

Plan for the Chapter 4

In this fourth article (or chapter), we will review the topics of the Fiber security & logging middlewares and useful boilerplates.

Yes, these are the main topics 👇

📝 Table of contents

• Working with Security middlewares
  • Helmet middleware
  • CSRF middleware
  • Limiter middleware
• Explore Logging middleware
• Useful Fiber Boilerplates
• Summary

Working with Security middlewares

Security middlewares in the Fiber web framework perform the task of protecting your application from various types of hacker attacks. This is critical for projects that work in production with real users.

☝️ Note: However, even if you don't plan to put your project into production now, knowing about such middleware is still a useful skill.

↑ Table of contents

Helmet middleware

Helmet middleware helps to secure our Fiber application by setting various HTTP headers:

• XSS Protection
• Content-Type No Sniff
• X-Frame Options
• HSTS Max Age
• CSP Report Only
• Exclude Subdomains & Preload Enabled
• Content Security & Referrer Policies

// ./go/security_middlewares.go

import "github.com/gofiber/helmet/v2"

// ...

// Use middlewares for each route
app.Use(
  helmet.New(), // add Helmet middleware
)

↑ Table of contents

CSRF middleware

CSRF middleware for Fiber that provides Cross-Site request forgery protection by passing a CSRF token via cookies.

This cookie value will be used to compare against the client CSRF token in the POST requests. When the CSRF token is invalid, this middleware will delete the csrf_ cookie and return the fiber.ErrForbidden error.

// ./go/security_middlewares.go

import "github.com/gofiber/fiber/v2/middleware/crsf"

// ...

// Use middlewares for each route
app.Use(
  csrf.New(), // add CSRF middleware
)

We can retrieve the CSRF token with c.Locals(key), where key is the option name in the custom middleware configuration.

The CSRF middleware custom config may look like this:

// Set config for CSRF middleware
csrfConfig := csrf.Config{
  KeyLookup:      "header:X-Csrf-Token", // string in the form of '<source>:<key>' that is used to extract token from the request
  CookieName:     "my_csrf_",            // name of the session cookie
  CookieSameSite: "Strict",              // indicates if CSRF cookie is requested by SameSite
  Expiration:     3 * time.Hour,         // expiration is the duration before CSRF token will expire
  KeyGenerator:   utils.UUID,            // creates a new CSRF token
}

// Use middlewares for each route
app.Use(
  csrf.New(csrfConfig), // add CSRF middleware with config
)

↑ Table of contents

Limiter middleware

Limiter middleware for Fiber used to limit repeated requests to public APIs or endpoints such as password reset etc. Moreover, useful for API clients, web crawling, or other tasks that need to be throttled.

// ./go/security_middlewares.go

import "github.com/gofiber/fiber/v2/middleware/limiter"

// ...

// Use middlewares for each route
app.Use(
  limiter.New(), // add Limiter middleware
)

Most of the time, you will probably be using this middleware along with your configuration. It's easy to add a config like this:

// Set config for Limiter middleware
limiterConfig := limiter.Config{
  Next: func(c *fiber.Ctx) bool {
    return c.IP() == "127.0.0.1" // limit will apply to this IP
  },
  Max:        20,                // max count of connections
  Expiration: 30 * time.Second,  // expiration time of the limit
  Storage:    myCustomStorage{}, // used to store the state of the middleware
  KeyGenerator: func(c *fiber.Ctx) string {
    return c.Get("x-forwarded-for") // allows you to generate custom keys
  },
  LimitReached: func(c *fiber.Ctx) error {
    return c.SendFile("./too-fast-page.html") // called when a request hits the limit
  },
}

// Use middlewares for each route
app.Use(
  limiter.New(limiterConfig), // add Limiter middleware with config
)

↑ Table of contents

Explore Logging middleware

Like any other framework, Fiber also has its built-in middleware for logging HTTP request/response details and displaying results in the console.

Let's look at an example of what this might look like:

// ./go/logger_middlewares.go

import "github.com/gofiber/fiber/v2/middleware/logger"

// ...

// Use middlewares for each route
app.Use(
  logger.New(), // add Logger middleware
)

And the console output looks like this:

08:17:42 | 404 |   85ms |  127.0.0.1 | GET   | /v1/user/123 
08:18:07 | 204 |  145ms |  127.0.0.1 | POST  | /v1/webhook/postmark 
08:19:53 | 201 |  138ms |  127.0.0.1 | PUT   | /v1/article/create 

Yes, Logger middleware connects in the same way as the middleware reviewed earlier. Furthermore, we can save all logs to a file, not console output, like this:

// Define file to logs
file, err := os.OpenFile("./my_logs.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
if err != nil {
  log.Fatalf("error opening file: %v", err)
}
defer file.Close()

// Set config for logger
loggerConfig := logger.Config{
  Output: file, // add file to save output
}

// Use middlewares for each route
app.Use(
  logger.New(loggerConfig), // add Logger middleware with config
)

↑ Table of contents

Useful Fiber Boilerplates

Fiber has already gathered a friendly community of programmers from all over the world. Every day, they share new and interesting packages and templates, which make starting a new project easier for us.

Boilerplate projects not only allow you to create a complete application structure with all the settings, but also a better understanding of the principle of code organization in the ecosystem of the web framework on a real example.

Here we will only look at two of the most popular examples from the large number of such projects used by Fiber community and authors. But we can always find and use others, or even create our own and offer them to the community!

↑ Table of contents

The official boilerplate application template

This template was specially created by the authors of Fiber for a quick enter to the framework, without additional third-party packages. The application is specially designed to run in the Docker container.

↑ Table of contents

The Gowebly project

A next-generation CLI tool that makes it easy to create amazing web applications with Go on the backend (included Fiber), using htmx, hyperscript or Alpine.js, and the most popular CSS frameworks on the frontend.

Main features:

• 100% free and open source under the Apache 2.0 license.
• For any developer's level of knowledge and technical expertise, as the intelligent CLI does most of the routine project setup for you, creates an understandable structure, and prepares code for use and deployment in production.
• Cross-platform and multi-architecture allows successful running on any GNU/Linux distros, Microsoft Windows (including WSL) and Apple macOS.
• Well-documented, includes translations in many other languages (Русский, 简体中文, Español).
• Enables you to start a new project faster with Go, htmx, hyperscript or Alpine.js libraries.
• Supports the built-in net/http package and the most popular Go web frameworks and routers out of the box, such as Fiber, Gin, Echo, Chi, HttpRouter, Gorilla/Mux and PocketBase.
• Supports the most popular CSS frameworks out of the box, such as Tailwind CSS, daisyUI, Flowbite, Preline UI, UnoCSS, Bootstrap and Bulma.
• Supports a new JavaScript runtime environment called Bun for the frontend.
• Supports a way to build HTML with Go using the Templ package.
• Supports a live-reload mode for your Go code and frontend files using Air tool.
• Includes a basic config for golangci-lint for quick setup.
• Ready-to-use Dockerfile and Docker Compose files to deploy your application in any environment.
• Ready-to-install as PWA (Progressive Web App) in your browser or mobile device.
• Has a library of user-friendly helpers for your Go code.

↑ Table of contents

The Create Go App project

When talking about boilerplate packages, I can't help but mention a project that has already helped many developers (myself included) to create new Go projects in a matter of minutes.

The project is a handy interactive CLI with which you can easily create a full-fledged web application in just a couple of clicks:

• Out of the box, the project has its own fully configured Fiber REST API application template with automatic Swagger documentation and authorization of requests via JWT token.
• The background part will be generated with Vite.js, and you are free to choose absolutely any startup template for React, Preact, Vue, Svelte, web components, vanilla JavaScript or TypeScript and so on.
• Specifically configured roles and playbooks for the Ansible to deploy the application in isolated Docker containers on a remote server.

↑ Table of contents

Summary

Wow, here's a summary of the chapter you passed! We learned how easy it is to make our Fiber application secure by adding some built-in middlewares.

Then there was a detailed breakdown of how the logging system works, which will help us more than once in future articles in this series.

Next time, we'll learn even more about utility middlewares, external Fiber middlewares and the third-party packages for this wonderful web framework.

Stay tuned, don't switch! 😉

↑ Table of contents

Photos and videos by

• Kolya Korzh https://unsplash.com/photos/UOq-FqdlTpw

P.S.

If you want more articles (like this) on this blog, then post a comment below and subscribe to me. Thanks! 😻

❗️ You can support me on Boosty, both on a permanent and on a one-time basis. All proceeds from this way will go to support my OSS projects and will energize me to create new products and articles for the community.

And of course, you can help me make developers' lives even better! Just connect to one of my projects as a contributor. It's easy!

My main projects that need your help (and stars) 👇

• 🔥 gowebly: A next-generation CLI tool that makes it easy to create amazing web applications with Go on the backend, using htmx, hyperscript or Alpine.js and the most popular CSS frameworks on the frontend.
• ✨ create-go-app: Create a new production-ready project with Go backend, frontend and deploy automation by running one CLI command.

Other my small projects: yatr, gosl, json2csv, csv2api.