feat: add response cache to all requests

anilist.go

@@ -106,6 +106,7 @@ func handleAniListAnimeSearch(idMap *ConcurrentMap, permaSkipIds []string) http.
 				log.Printf("Error writing error response: %v", writeErr)
 			}
 		} else {
+			w.WriteHeader(http.StatusOK)
 			if _, writeErr := w.Write(search); writeErr != nil {
 				log.Printf("Error writing response: %v", writeErr)
 			}

go.mod

@@ -3,3 +3,5 @@ module github.com/gabehf/sonarr-anime-importer
 go 1.23.0
 
 require github.com/darenliang/jikan-go v1.2.3
+
+require github.com/patrickmn/go-cache v2.1.0+incompatible

go.sum

@@ -1,2 +1,4 @@
 github.com/darenliang/jikan-go v1.2.3 h1:Nw6ykJU47QW3rwiIBWHyy1cBNM1Cxsz0AVCdqIN278A=
 github.com/darenliang/jikan-go v1.2.3/go.mod h1:rv7ksvNqc1b0UK7mf1Uc3swPToJXd9EZQLz5C38jk9Q=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=

helpers.go

@@ -1,6 +1,8 @@
 package main
 
 import (
+	"fmt"
+	"net/http"
 	"net/url"
 	"strconv"
 )
@@ -28,3 +30,7 @@ func FullAnimeTitle(title, engtitle string) string {
 		return title
 	}
 }
+
+func RequestString(r *http.Request) string {
+	return fmt.Sprintf("%s %s?%s", r.Method, r.URL.Path, r.URL.RawQuery)
+}

main.go

@@ -11,6 +11,8 @@ import (
 	"strings"
 	"sync"
 	"time"
+
+	"github.com/patrickmn/go-cache"
 )
 
 type ResponseItem struct {
@@ -57,9 +59,15 @@ func main() {
 	if permaSkipAniListStr != "" {
 		log.Printf("Always skipping AniList IDs: %v\n", permaSkipAniListIds)
 	}
-	buildIdMapMiddleware := newRebuildStaleIdMapMiddleware(idMap)
-	http.HandleFunc("/v1/mal/anime", loggerMiddleware(buildIdMapMiddleware(handleMalAnimeSearch(idMap, permaSkipMalIds))))
-	http.HandleFunc("/v1/anilist/anime", loggerMiddleware(buildIdMapMiddleware(handleAniListAnimeSearch(idMap, permaSkipAniListIds))))
+	log.Printf("Preparing cache...")
+	c := cache.New(10*time.Minute, 15*time.Minute)
+	middleware := []Middleware{
+		loggerMiddleware,
+		newCacheMiddleware(c),
+		newRebuildStaleIdMapMiddleware(idMap),
+	}
+	http.HandleFunc("/v1/mal/anime", ChainMiddleware(handleMalAnimeSearch(idMap, permaSkipMalIds), middleware...))
+	http.HandleFunc("/v1/anilist/anime", ChainMiddleware(handleAniListAnimeSearch(idMap, permaSkipAniListIds), middleware...))
 	log.Println("Listening on :3333")
 
 	srv := &http.Server{

mal.go

@@ -21,6 +21,7 @@ func handleMalAnimeSearch(idMap *ConcurrentMap, permaSkipMalIds []string) http.H
 				log.Printf("Error writing error response: %v", writeErr)
 			}
 		} else {
+			w.WriteHeader(http.StatusOK)
 			if _, writeErr := w.Write([]byte(search)); writeErr != nil {
 				log.Printf("Error writing response: %v", writeErr)
 			}

middleware.go

@@ -1,13 +1,31 @@
 package main
 
 import (
+	"bytes"
 	"log"
 	"net/http"
 	"time"
+
+	"github.com/patrickmn/go-cache"
 )
 
-func newRebuildStaleIdMapMiddleware(idMap *ConcurrentMap) func(http.Handler) http.Handler {
-	return func(next http.Handler) http.Handler {
+// from https://medium.com/@chrisgregory_83433/chaining-middleware-in-go-918cfbc5644d
+type Middleware func(http.HandlerFunc) http.HandlerFunc
+
+func ChainMiddleware(h http.HandlerFunc, m ...Middleware) http.HandlerFunc {
+	if len(m) < 1 {
+		return h
+	}
+	wrapped := h
+	// loop in reverse to preserve middleware order
+	for i := len(m) - 1; i >= 0; i-- {
+		wrapped = m[i](wrapped)
+	}
+	return wrapped
+}
+
+func newRebuildStaleIdMapMiddleware(idMap *ConcurrentMap) func(http.HandlerFunc) http.HandlerFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
 		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 			if time.Since(lastBuiltAnimeIdList) > 24*time.Hour {
 				log.Println("Anime ID association table expired, building new table...")
@@ -18,9 +36,47 @@ func newRebuildStaleIdMapMiddleware(idMap *ConcurrentMap) func(http.Handler) htt
 	}
 }
 
-func loggerMiddleware(next http.Handler) http.HandlerFunc {
+func loggerMiddleware(next http.HandlerFunc) http.HandlerFunc {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		log.Printf("%s %s?%s", r.Method, r.URL.Path, r.URL.RawQuery)
+		log.Print(RequestString(r))
 		next.ServeHTTP(w, r)
 	})
 }
+
+type cacheResponseWriter struct {
+	http.ResponseWriter
+	status int
+	body   *bytes.Buffer
+}
+
+func (w *cacheResponseWriter) WriteHeader(statusCode int) {
+	w.status = statusCode
+	w.ResponseWriter.WriteHeader(statusCode)
+}
+
+func (w *cacheResponseWriter) Write(b []byte) (int, error) {
+	w.body.Write(b) // Capture body
+	return w.ResponseWriter.Write(b)
+}
+
+func newCacheMiddleware(c *cache.Cache) func(http.HandlerFunc) http.HandlerFunc {
+	return func(next http.HandlerFunc) http.HandlerFunc {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			key := RequestString(r)
+			if cachedResp, found := c.Get(key); found {
+				log.Println("Responding with cached response")
+				w.WriteHeader(http.StatusOK)
+				w.Write(cachedResp.([]byte))
+				return
+			}
+			crw := &cacheResponseWriter{
+				ResponseWriter: w,
+				body:           &bytes.Buffer{},
+			}
+			next.ServeHTTP(crw, r)
+			if crw.status == http.StatusOK {
+				c.Set(key, crw.body.Bytes(), cache.DefaultExpiration)
+			}
+		})
+	}
+}