go1.22 net/http package new feature support path params pattern

todos.go

package main

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

type TODO struct {
	UUID        string `json:"id"`
	Title       string `json:"title"`
	Description string `json:"description"`
	Completed   bool   `json:"completed"`
}

type TODOList struct {
	TODOs []*TODO
	mu    sync.Mutex
}

func (t *TODOList) Add(todo *TODO) {
	t.mu.Lock()
	defer t.mu.Unlock()
	t.TODOs = append(t.TODOs, todo)
}

func (t *TODOList) Remove(uuid string) {
	t.mu.Lock()
	defer t.mu.Unlock()
	t.TODOs = slices.DeleteFunc(t.TODOs, func(todo *TODO) bool {
		return todo.UUID == uuid
	})
}

func (t *TODOList) Get(uuid string) *TODO {
	t.mu.Lock()
	defer t.mu.Unlock()
	i := slices.IndexFunc(t.TODOs, func(todo *TODO) bool {
		return todo.UUID == uuid
	})
	if i == -1 {
		return nil
	}
	return t.TODOs[i]
}

func (t *TODOList) Update(todo *TODO) {
	t.mu.Lock()
	defer t.mu.Unlock()
	i := slices.IndexFunc(t.TODOs, func(t *TODO) bool {
		return t.UUID == todo.UUID
	})
	if i == -1 {
		return
	}
	t.TODOs[i] = todo
}

func (t *TODOList) All() []*TODO {
	t.mu.Lock()
	defer t.mu.Unlock()
	return t.TODOs
}

func (t *TODOList) Completed() []*TODO {
	t.mu.Lock()
	defer t.mu.Unlock()
	var completed []*TODO
	for _, todo := range t.TODOs {
		if todo.Completed {
			completed = append(completed, todo)
		}
	}
	return completed
}

func (t *TODOList) Pending() []*TODO {
	t.mu.Lock()
	defer t.mu.Unlock()
	var pending []*TODO
	for _, todo := range t.TODOs {
		if !todo.Completed {
			pending = append(pending, todo)
		}
	}
	return pending
}

func (t *TODOList) Clear() {
	t.mu.Lock()
	defer t.mu.Unlock()
	t.TODOs = nil
}

func (t *TODOList) Toggle(uuid string) {
	t.mu.Lock()
	defer t.mu.Unlock()
	i := slices.IndexFunc(t.TODOs, func(todo *TODO) bool {
		return todo.UUID == uuid
	})
	if i == -1 {
		return
	}
	t.TODOs[i].Completed = !t.TODOs[i].Completed
}

func (t *TODOList) ToggleAll() {
	t.mu.Lock()
	defer t.mu.Unlock()
	for _, todo := range t.TODOs {
		todo.Completed = !todo.Completed
	}
}

func (t *TODOList) MarkComplete(uuid string) {
	t.mu.Lock()
	defer t.mu.Unlock()
	i := slices.IndexFunc(t.TODOs, func(todo *TODO) bool {
		return todo.UUID == uuid
	})
	if i == -1 {
		return
	}
	t.TODOs[i].Completed = true
}

func (t *TODOList) CompleteAll() {
	t.mu.Lock()
	defer t.mu.Unlock()
	for _, todo := range t.TODOs {
		todo.Completed = true
	}
}

func (t *TODOList) MarkPending(uuid string) {
	t.mu.Lock()
	defer t.mu.Unlock()
	i := slices.IndexFunc(t.TODOs, func(todo *TODO) bool {
		return todo.UUID == uuid
	})
	if i == -1 {
		return
	}
	t.TODOs[i].Completed = false
}

func (t *TODOList) PendingAll() {
	t.mu.Lock()
	defer t.mu.Unlock()
	for _, todo := range t.TODOs {
		todo.Completed = false
	}
}

func main() {
	items := &TODOList{TODOs: []*TODO{}}

	http.HandleFunc("/todos", func(w http.ResponseWriter, r *http.Request) {
		switch r.Method {
		case "GET":
			err := json.NewEncoder(w).Encode(items.All())
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
		case "POST":
			var todo TODO
			err := json.NewDecoder(r.Body).Decode(&todo)
			if err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			items.Add(&todo)
		}
	})

	http.HandleFunc("/todos/{uuid}", func(w http.ResponseWriter, r *http.Request) {
		uuid := r.PathValue("uuid")

		switch r.Method {
		case "GET":
			todo := items.Get(uuid)
			if todo == nil {
				http.Error(w, "Not Found", http.StatusNotFound)
				return
			}
			err := json.NewEncoder(w).Encode(todo)
			if err != nil {
				http.Error(w, err.Error(), http.StatusInternalServerError)
				return
			}
		case "PUT":
			var todo TODO
			err := json.NewDecoder(r.Body).Decode(&todo)
			if err != nil {
				http.Error(w, err.Error(), http.StatusBadRequest)
				return
			}
			todo.UUID = uuid
			items.Update(&todo)
		case "DELETE":
			items.Remove(uuid)
		}
	})

	http.HandleFunc("/todos/{uuid}/toggle", func(w http.ResponseWriter, r *http.Request) {
		if r.Method != "POST" {
			http.Error(w, "Method Not Allowed", http.StatusMethodNotAllowed)
			return
		}
		uuid := r.PathValue("uuid")
		items.Toggle(uuid)
	})

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