add k/v store

store/store.go

@@ -0,0 +1,68 @@
+// Package store implements a synchronous in-memory K/V store
+// fronted by an HTTP server.
+package store
+
+import (
+	"io"
+	"net/http"
+	"sync"
+)
+
+type Map struct {
+	m sync.Map
+}
+
+func New(from map[string]string) *Map {
+	var m Map
+	for k, v := range from {
+		m.Set(k, v)
+	}
+	return &m
+}
+
+func (m *Map) Get(k string) (string, bool) {
+	r, ok := m.m.Load(k)
+	return r.(string), ok
+}
+
+func (m *Map) Set(k, v string) {
+	m.m.Store(k, v)
+}
+
+func (m *Map) Delete(k string) {
+	m.m.Delete(k)
+}
+
+func (m *Map) Router() http.Handler {
+	r := http.NewServeMux()
+	r.HandleFunc("GET /{key}", m.get)
+	r.HandleFunc("PUT /{key}", m.set)
+	r.HandleFunc("POST /{key}", m.set)
+	r.HandleFunc("DELETE /{key}", m.delete)
+	return r
+}
+
+func (m *Map) get(w http.ResponseWriter, r *http.Request) {
+	k := r.PathValue("key")
+	v, ok := m.Get(k)
+	if !ok {
+		http.Error(w, "not found", http.StatusNotFound)
+	}
+	io.WriteString(w, v)
+}
+
+func (m *Map) set(w http.ResponseWriter, r *http.Request) {
+	k := r.PathValue("key")
+	b, err := io.ReadAll(r.Body)
+	if err != nil {
+		http.Error(w, err.Error(), http.StatusBadRequest)
+	}
+	m.Set(k, string(b))
+	w.WriteHeader(http.StatusNoContent)
+}
+
+func (m *Map) delete(w http.ResponseWriter, r *http.Request) {
+	k := r.PathValue("key")
+	m.Delete(k)
+	w.WriteHeader(http.StatusNoContent)
+}