Add rate limiter to register endpoint

go.mod

@@ -23,6 +23,7 @@ require (
 	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
 	golang.org/x/net v0.0.0-20201029221708-28c70e62bb1d // indirect
 	golang.org/x/sys v0.0.0-20201029080932-201ba4db2418 // indirect
+	golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba // indirect
 	google.golang.org/genproto v0.0.0-20201030142918-24207fddd1c3 // indirect
 	google.golang.org/grpc v1.33.1 // indirect
 	google.golang.org/protobuf v1.25.0 // indirect

go.sum

@@ -97,6 +97,8 @@ golang.org/x/sys v0.0.0-20201029080932-201ba4db2418 h1:HlFl4V6pEMziuLXyRkm5BIYq1
 golang.org/x/sys v0.0.0-20201029080932-201ba4db2418/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba h1:O8mE0/t419eoIwhTFpKVkHiTs/Igowgfkj25AcZrtiE=
+golang.org/x/time v0.0.0-20210220033141-f8bda1e9f3ba/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20181030221726-6c7e314b6563/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
 golang.org/x/tools v0.0.0-20190114222345-bf090417da8b/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

internal/goscrobble/ratelimiter.go

@@ -0,0 +1,56 @@
+package goscrobble
+
+import (
+	"sync"
+
+	"golang.org/x/time/rate"
+)
+
+// IPRateLimiter
+type IPRateLimiter struct {
+	ips map[string]*rate.Limiter
+	mu  *sync.RWMutex
+	r   rate.Limit
+	b   int
+}
+
+// NewIPRateLimiter
+func NewIPRateLimiter(r rate.Limit, b int) *IPRateLimiter {
+	i := &IPRateLimiter{
+		ips: make(map[string]*rate.Limiter),
+		mu:  &sync.RWMutex{},
+		r:   r,
+		b:   b,
+	}
+
+	return i
+}
+
+// AddIP creates a new rate limiter and adds it to the ips map,
+// using the IP address as the key
+func (i *IPRateLimiter) AddIP(ip string) *rate.Limiter {
+	i.mu.Lock()
+	defer i.mu.Unlock()
+
+	limiter := rate.NewLimiter(i.r, i.b)
+
+	i.ips[ip] = limiter
+
+	return limiter
+}
+
+// GetLimiter returns the rate limiter for the provided IP address if it exists.
+// Otherwise calls AddIP to add IP address to the map
+func (i *IPRateLimiter) GetLimiter(ip string) *rate.Limiter {
+	i.mu.Lock()
+	limiter, exists := i.ips[ip]
+
+	if !exists {
+		i.mu.Unlock()
+		return i.AddIP(ip)
+	}
+
+	i.mu.Unlock()
+
+	return limiter
+}

internal/goscrobble/server.go

@@ -19,9 +19,13 @@ type spaHandler struct {
 }
 
 type jsonResponse struct {
-	Err string `json:"error"`
+	Err string `json:"error,omitempty"`
+	Msg string `json:"message,omitempty"`
 }
 
+// Limits to 1 req / 10 sec
+var limiter = NewIPRateLimiter(0.1, 1)
+
 // HandleRequests - Boot HTTP!
 func HandleRequests() {
 	// Create a new router
@@ -36,7 +40,7 @@ func HandleRequests() {
 	v1.HandleFunc("/profile/{id}", jwtMiddleware(serveEndpoint))
 
 	// No Auth
-	v1.HandleFunc("/register", handleRegister).Methods("POST")
+	v1.HandleFunc("/register", limitMiddleware(handleRegister)).Methods("POST")
 	v1.HandleFunc("/login", serveEndpoint).Methods("POST")
 	v1.HandleFunc("/logout", serveEndpoint).Methods("POST")
 
@@ -62,7 +66,7 @@ func throwUnauthorized(w http.ResponseWriter, m string) {
 	http.Error(w, err.Error(), http.StatusUnauthorized)
 }
 
-// throwUnauthorized - Throws a 403 :
+// throwUnauthorized - Throws a 403
 func throwBadReq(w http.ResponseWriter, m string) {
 	jr := jsonResponse{
 		Err: m,
@@ -72,6 +76,15 @@ func throwBadReq(w http.ResponseWriter, m string) {
 	http.Error(w, err.Error(), http.StatusBadRequest)
 }
 
+// generateJsonMessage - Generates a message:str response
+func generateJsonMessage(m string) []byte {
+	jr := jsonResponse{
+		Msg: m,
+	}
+	js, _ := json.Marshal(&jr)
+	return js
+}
+
 // tokenMiddleware - Validates token to a user
 func tokenMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
@@ -90,6 +103,19 @@ func jwtMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	}
 }
 
+// limitMiddleware - Rate limits important stuff
+func limitMiddleware(next http.HandlerFunc) http.HandlerFunc {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		limiter := limiter.GetLimiter(r.RemoteAddr)
+		if !limiter.Allow() {
+			http.Error(w, http.StatusText(http.StatusTooManyRequests), http.StatusTooManyRequests)
+			return
+		}
+
+		next(w, r)
+	})
+}
+
 // API ENDPOINT HANDLING
 
 // handleRegister - Does as it says!
@@ -108,8 +134,9 @@ func handleRegister(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	// Lets trick 'em for now ;) ;)
-	fmt.Fprintf(w, "{}")
+	msg := generateJsonMessage("User created succesfully")
+	w.WriteHeader(http.StatusCreated)
+	w.Write(msg)
 }
 
 // serveEndpoint - API stuffs