Fiber is an Express inspired web framework build on top of Fasthttp, the fastest HTTP engine for Go. Designed to ease things up for fast development with zero memory allocation and performance in mind.

First of all, download and install Go. 1.11 or higher is required.

Installation is done using the go get command:

go get -u github.com/gofiber/fiber

Embedded below is essentially simplest Fiber app, which you can create.

package main

import "github.com/gofiber/fiber"

func main() {
  app := fiber.New()

  app.Get("/", func(c *fiber.Ctx) {
    c.Send("Hello, World!")
  })

  app.Listen(3000)
}

go run server.go

Browse to http://localhost:3000 and you should see Hello, World! on the page.

Routing refers to determining how an application responds to a client request to a particular endpoint, which is a URI (or path) and a specific HTTP request method (GET, PUT, POST and so on).

{% hint style="info" %} Each route can have multiple handler functions, that are executed when the route is matched. {% endhint %}

Route definition takes the following structures:

// Function signature
app.Method(path string, ...func(*fiber.Ctx))

• app is an instance of Fiber.
• Method is an HTTP request method, in capitalization: Get, Put, Post, etc.
• path is a virtual path on the server.
• func(*fiber.Ctx) is a callback function containing the Context executed when the route is matched.

Simple route

// Respond with "Hello, World!" on root path, "/"
app.Get("/", func(c *fiber.Ctx) {
  c.Send("Hello, World!")
})

Parameters

// GET http://localhost:8080/hello%20world

app.Get("/:value", func(c *fiber.Ctx) {
  c.Send("Get request with value: " + c.Params("value"))
  // => Get request with value: hello world
})

Optional parameter

// GET http://localhost:3000/john

app.Get("/:name?", func(c *fiber.Ctx) {
  if c.Params("name") != "" {
    c.Send("Hello " + c.Params("name"))
    // => Hello john
  } else {
    c.Send("Where is john?")
  }
})

Wildcards

// GET http://localhost:3000/api/user/john

app.Get("/api/*", func(c *fiber.Ctx) {
  c.Send("API path: " + c.Params("*"))
  // => API path: user/john
})

To serve static files such as images, CSS and JavaScript files, replace your function handler with a file or directory string.

Function signature:

app.Static(prefix, root string)

Use the following code to serve files in a directory named ./public:

app := fiber.New()

app.Static("/", "./public") 

app.Listen(8080)

Now, you can load the files that are in the ./public directory:

http://localhost:8080/hello.html
http://localhost:8080/js/jquery.js
http://localhost:8080/css/style.css