feat(api): add server-side caching for requests that could benefit (#3463)

* feat(api): add server-side caching for requests that could benefit for them

* fix(tests): do not cache responses while in tests

* fix: remove commented out leftover code

* chore(deps): update dependency html-webpack-plugin to v5.5.4

* Bundle embedded web app

* fix: remove caching for web app assets under test

* chore(tests): re-enable temporarily disabled test

* chore(deps): update dependency typescript to v5.3.3

* Bundle embedded web app

* chore(deps): update dependency npm to v10.2.5

* Bundle embedded web app

---------

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: Owncast <owncast@owncast.online>

controllers/hls.go

@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"time"
 
 	"github.com/owncast/owncast/config"
 	"github.com/owncast/owncast/core"
@@ -13,8 +14,19 @@ import (
 	"github.com/owncast/owncast/models"
 	"github.com/owncast/owncast/router/middleware"
 	"github.com/owncast/owncast/utils"
+	log "github.com/sirupsen/logrus"
+	cache "github.com/victorspringer/http-cache"
+	"github.com/victorspringer/http-cache/adapter/memory"
 )
 
+type FileServerHandler struct {
+	HLSPath string
+}
+
+func (fsh *FileServerHandler) ServeHTTP(rw http.ResponseWriter, r *http.Request) {
+	http.ServeFile(rw, r, fsh.HLSPath)
+}
+
 // HandleHLSRequest will manage all requests to HLS content.
 func HandleHLSRequest(w http.ResponseWriter, r *http.Request) {
 	// Sanity check to limit requests to HLS file types.
@@ -23,6 +35,26 @@ func HandleHLSRequest(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	responseCache, err := memory.NewAdapter(
+		memory.AdapterWithAlgorithm(memory.LRU),
+		memory.AdapterWithCapacity(20),
+		memory.AdapterWithStorageCapacity(209_715_200),
+	)
+	if err != nil {
+		log.Warn("unable to create web cache", err)
+	}
+
+	// Since HLS segments cannot be changed once they're rendered, we can cache
+	// individual segments for a long time.
+	longTermHLSSegmentCache, err := cache.NewClient(
+		cache.ClientWithAdapter(responseCache),
+		cache.ClientWithTTL(30*time.Second),
+		cache.ClientWithExpiresHeader(),
+	)
+	if err != nil {
+		log.Warn("unable to create web cache client", err)
+	}
+
 	requestedPath := r.URL.Path
 	relativePath := strings.Replace(requestedPath, "/hls/", "", 1)
 	fullPath := filepath.Join(config.HLSStoragePath, relativePath)
@@ -48,6 +80,10 @@ func HandleHLSRequest(w http.ResponseWriter, r *http.Request) {
 	} else {
 		cacheTime := utils.GetCacheDurationSecondsForPath(relativePath)
 		w.Header().Set("Cache-Control", "public, max-age="+strconv.Itoa(cacheTime))
+
+		fileServer := &FileServerHandler{HLSPath: fullPath}
+		longTermHLSSegmentCache.Middleware(fileServer).ServeHTTP(w, r)
+		return
 	}
 
 	middleware.EnableCors(w)