Go 1.22: A New Era of Routing Simplicity

Introduction

Go 1.22 introduces a game-changing improvement to web routing with a more intuitive and powerful ServeMux syntax. This article explores the new routing capabilities and demonstrates how they simplify web application development.

Old vs New: Routing Syntax Comparison

Traditional Routing (Pre-1.22)

func main() {
    http.HandleFunc("/users", func(w http.ResponseWriter, r *http.Request) {
        // Complex manual parsing of paths and methods
        if r.Method != http.MethodGet {
            http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
            return
        }
    })
}

New Routing in Go 1.22

func main() {
    mux := http.NewServeMux()
    mux.HandleFunc("GET /users/{id}", func(w http.ResponseWriter, r *http.Request) {
        // Automatic method and path parameter handling
        id := r.PathValue("id")
        // Clean, straightforward code
    })
}

Demonstration Project: Note Management API

Let's create a simple note management application that showcases the new routing capabilities.

Project Structure

notes-app/
├── compose.yml
├── Dockerfile
└── main.go

compose.yml:

services:
  app:
    build: .
    ports:
      - "8080:8080"

Dockerfile:

FROM golang:1.22-alpine

WORKDIR /app

COPY go.mod main.go ./
RUN go build -o notes-app

EXPOSE 8080

CMD ["./notes-app"]

main.go:

package main

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

type Note struct {
	ID      string `json:"id"`
	Content string `json:"content"`
}

var notes = map[string]Note{
	"1": {ID: "1", Content: "First note"},
}

func main() {
	mux := http.NewServeMux()

	mux.HandleFunc("GET /notes/{id}", func(w http.ResponseWriter, r *http.Request) {
		id := r.PathValue("id")
		note, ok := notes[id]
		if !ok {
			http.NotFound(w, r)
			return
		}
		json.NewEncoder(w).Encode(note)
	})

	mux.HandleFunc("POST /notes", func(w http.ResponseWriter, r *http.Request) {
		var note Note
		json.NewDecoder(r.Body).Decode(&note)
		note.ID = "2"
		notes[note.ID] = note
		w.WriteHeader(http.StatusCreated)
	})

	http.ListenAndServe(":8080", mux)
}

Running the Project

To run the project:

```
go mod init my.go-routing
docker compose up --build
http://localhost:8080/notes/1
```