feat(api): create api proxy/ratelimiting/metrics

services/web-proxy/rate_limit.go

@@ -0,0 +1,43 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"web-proxy/redis_rate"
+)
+
+func is_api_ratelimited(rw http.ResponseWriter, r *http.Request) bool {
+	var limit int
+	var key string
+
+	if r.Header.Get("X-PluralKit-App") == token2 {
+		limit = 20
+		key = "token2"
+	} else {
+		limit = 2
+		key = r.Header.Get("Fly-Client-IP")
+	}
+
+	res, err := limiter.Allow(r.Context(), "ratelimit:"+key, redis_rate.Limit{
+		Period: time.Second,
+		Rate:   limit,
+		Burst:  5,
+	})
+	if err != nil {
+		panic(err)
+	}
+
+	rw.Header().Set("X-RateLimit-Limit", fmt.Sprint(limit))
+	rw.Header().Set("X-RateLimit-Remaining", fmt.Sprint(res.Remaining))
+	rw.Header().Set("X-RateLimit-Reset", fmt.Sprint(time.Now().Add(res.ResetAfter).UnixNano()/1_000_000))
+
+	if res.Allowed < 1 {
+		rw.WriteHeader(429)
+		rw.Write([]byte(`{"message":"429: too many requests","retry_after":` + fmt.Sprint(res.RetryAfter.Milliseconds()) + `,"code":0}`))
+		return true
+	}
+
+	return false
+}