initial commit of api

cmd/api/http/handlers.go

@@ -0,0 +1,69 @@
+package http
+
+import (
+	"encoding/json"
+	"fmt"
+	"io/ioutil"
+	"math/rand"
+	"net/http"
+	"time"
+)
+
+func (s *Server) setLimit(w http.ResponseWriter, r *http.Request) {
+	var input struct {
+		Limit int `json:"limit"`
+	}
+
+	bodyBytes, err := ioutil.ReadAll(r.Body)
+	if err != nil {
+		s.respondError(w, http.StatusBadRequest, err)
+		return
+	}
+
+	err = json.Unmarshal(bodyBytes, &input)
+	if err != nil {
+		s.respondError(w, http.StatusBadRequest, err)
+	}
+
+	var rl RateLimiter
+	rl, err = NewMaxConcurrencyRateLimiter(input.Limit)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("setting new rate limiter: %+v\n", rl)
+	s.RateLimiter = rl
+}
+
+func (s *Server) getData(w http.ResponseWriter, r *http.Request) {
+	data := []struct {
+		Item1 string
+		Item2 string
+		Item3 string
+	}{
+		{
+			Item1: "books",
+			Item2: "hotdogs",
+			Item3: "trinkets",
+		},
+	}
+
+	bytes, err := json.Marshal(data)
+	if err != nil {
+		s.respondError(w, http.StatusInternalServerError, err)
+		return
+	}
+
+	// Sleep for a random amount of time up to 5 seconds.
+	time.Sleep(time.Duration(rand.Intn(500)) * time.Millisecond)
+
+	w.Write(bytes)
+
+	t := r.Context().Value("rate-limit-token").(*Token)
+	s.RateLimiter.Release(t)
+	return
+}
+
+func (s *Server) respondError(w http.ResponseWriter, statusCode int, err error) {
+	http.Error(w, err.Error(), statusCode)
+	return
+}