Add compression middleware

.gitignore

@@ -6,8 +6,7 @@
 *.test
 *.out
 go.work
-
 *.local
 .env
 dist/
-/book
+/book

go.mod

@@ -50,6 +50,7 @@ require (
 	github.com/Azure/go-autorest v14.2.0+incompatible // indirect
 	github.com/Azure/go-autorest/autorest/to v0.4.0 // indirect
 	github.com/AzureAD/microsoft-authentication-library-for-go v1.0.0 // indirect
+	github.com/andybalholm/brotli v1.1.0 // indirect
 	github.com/aws/aws-sdk-go v1.44.314 // indirect
 	github.com/aws/aws-sdk-go-v2 v1.20.0 // indirect
 	github.com/aws/aws-sdk-go-v2/aws/protocol/eventstream v1.4.11 // indirect

go.sum

@@ -147,6 +147,8 @@ github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRF
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
 github.com/alexflint/go-filemutex v0.0.0-20171022225611-72bdc8eae2ae/go.mod h1:CgnQgUtFrFz9mxFNtED3jI5tLDjKlOM+oUF/sTk6ps0=
 github.com/alexflint/go-filemutex v1.1.0/go.mod h1:7P4iRhttt/nUvUOrYIhcpMzv2G6CY9UnI16Z+UJqRyk=
+github.com/andybalholm/brotli v1.1.0 h1:eLKJA0d02Lf0mVpIDgYnqXcUn0GqVmEFny3VuID1U3M=
+github.com/andybalholm/brotli v1.1.0/go.mod h1:sms7XGricyQI9K10gOSf56VKKWS4oLer58Q+mhRPtnY=
 github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kdvxnR2qWY=
 github.com/apache/arrow/go/arrow v0.0.0-20210818145353-234c94e4ce64/go.mod h1:2qMFB56yOP3KzkB3PbYZ4AlUFg3a88F67TIx5lB/WwY=
 github.com/apache/arrow/go/arrow v0.0.0-20211013220434-5962184e7a30/go.mod h1:Q7yQnSMnLvcXlZ8RV+jwz/6y1rQTqbX6C82SndT52Zs=

internal/handler/site/middleware/compression.go

@@ -0,0 +1,28 @@
+package middleware
+
+import (
+	"net/http"
+	"io"
+
+	"github.com/andybalholm/brotli"
+	"github.com/oursky/pageship/internal/site"
+)
+
+type CompressedResponseWriter struct {
+	http.ResponseWriter
+	compressor io.WriteCloser
+}
+
+func (crw CompressedResponseWriter) Write(b []byte) (int, error) {
+	defer crw.compressor.Close()
+	return crw.compressor.Write(b)
+}
+
+func Compression(site *site.Descriptor, next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		crw := CompressedResponseWriter{w, brotli.HTTPCompressor(w, r)} //chooses compression method based on Accept-Encoding header and
+	                                                                    //also sets the Content-Encoding header
+		next.ServeHTTP(crw, r)
+	})
+}
+

internal/handler/site/site_handler.go

@@ -73,6 +73,7 @@ func (h *SiteHandler) serveFile(w http.ResponseWriter, r *http.Request) {
 	}
 	if info.Hash != "" {
 		w.Header().Set("ETag", fmt.Sprintf(`"%s"`, info.Hash))
+		w.Header().Set("Cache-Control", "public, max-age=31536000, no-cache")
 	}
 
 	reader := &lazyReader{