New DirOptions.Cache field for in-memory caching and pre-compression for the fastest possible static file server

Read HISTORY.md it contains a breaking change, second parameter of HandleDir should be iris.Dir(...) instead of just a string

relative to: https://github.com/kataras/iris/issues/1556#issuecomment-661057446


Former-commit-id: 14b48a06fb3b99287dff543932be2937a64233b9

_examples/file-server/embedding-gzipped-files-into-app/assets/js/jquery-2.1.1.js

@@ -1 +0,0 @@
-console.log("example");

_examples/file-server/embedding-gzipped-files-into-app/main.go

@@ -4,31 +4,39 @@ import (
 	"github.com/kataras/iris/v12"
 )
 
-// NOTE: need different tool than the "embedding-files-into-app" example.
+// How to run:
 //
-// Follow these steps first:
-// $ go get -u github.com/kataras/bindata/cmd/bindata
-// $ bindata ./assets/...
+// $ go get -u github.com/go-bindata/go-bindata/v3/go-bindata
+// $ go-bindata -prefix "../embedding-files-into-app/assets/" -fs ../embedding-files-into-app/assets/...
 // $ go run .
-// $ ./embedding-gzipped-files-into-app
-// "physical" files are not used, you can delete the "assets" folder and run the example.
+// Time to complete the compression and caching of [2/3] files: 31.9998ms
+// Total size reduced from 156.6 kB to:
+// br      (22.9 kB) [85.37%]
+// snappy  (41.7 kB) [73.37%]
+// gzip    (27.9 kB) [82.16%]
+// deflate (27.9 kB) [82.19%]
+
+var dirOptions = iris.DirOptions{
+	IndexName: "index.html",
+	// The `Compress` field is ignored
+	// when the file is cached (when Cache.Enable is true),
+	// because the cache file has a map of pre-compressed contents for each encoding
+	// that is served based on client's accept-encoding.
+	Compress: true, // true or false does not matter here.
+	Cache: iris.DirCacheOptions{
+		Enable:         true,
+		CompressIgnore: iris.MatchImagesAssets,
+		// Here, define the encodings that the cached files should be pre-compressed
+		// and served based on client's needs.
+		Encodings:       []string{"gzip", "deflate", "br", "snappy"},
+		CompressMinSize: 50, // files smaller than this size will NOT be compressed.
+		Verbose:         1,
+	},
+}
 
 func newApp() *iris.Application {
 	app := iris.New()
-
-	// Note the `GzipAsset` and `GzipAssetNames` are different from go-bindata's `Asset`,
-	// do not set the `Compress` option to true, instead
-	// use the `AssetValidator` option to manually set the content-encoding to "gzip".
-	app.HandleDir("/static", "./assets", iris.DirOptions{
-		Asset:      GzipAsset,
-		AssetInfo:  GzipAssetInfo,
-		AssetNames: GzipAssetNames,
-		AssetValidator: func(ctx iris.Context, name string) bool {
-			// ctx.Header("Vary", "Accept-Encoding")
-			ctx.Header("Content-Encoding", "gzip")
-			return true
-		},
-	})
+	app.HandleDir("/static", AssetFile(), dirOptions)
 	return app
 }
 

_examples/file-server/embedding-gzipped-files-into-app/main_test.go

@@ -70,7 +70,9 @@ var urls = []resource{
 // and secondly if the HandleDir had successfully registered
 // the routes and gave the correct response.
 func TestEmbeddingGzipFilesIntoApp(t *testing.T) {
+	dirOptions.Cache.Verbose = 0
 	app := newApp()
+
 	e := httptest.New(t, app)
 
 	if runtime.GOOS != "windows" {
@@ -81,17 +83,25 @@ func TestEmbeddingGzipFilesIntoApp(t *testing.T) {
 
 	for i, u := range urls {
 		url := u.String()
-		rawContents := u.loadFromBase("./assets")
+		rawContents := u.loadFromBase("../embedding-files-into-app/assets")
+		shouldBeCompressed := int64(len(rawContents)) >= dirOptions.Cache.CompressMinSize
 
-		response := e.GET(url).Expect()
+		request := e.GET(url)
+		if shouldBeCompressed {
+			request.WithHeader("Accept-Encoding", "gzip")
+		}
+		response := request.Expect()
 		response.ContentType(u.contentType(), app.ConfigurationReadOnly().GetCharset())
-		response.ContentEncoding("gzip")
+		if shouldBeCompressed {
+			response.ContentEncoding("gzip")
+		}
+
 		if expected, got := response.Raw().StatusCode, httptest.StatusOK; expected != got {
 			t.Fatalf("[%d] of '%s': expected %d status code but got %d", i, url, expected, got)
 		}
 		rawBody := response.Body().Raw()
 
-		func() {
+		if shouldBeCompressed {
 			reader, err := gzip.NewReader(strings.NewReader(rawBody))
 			defer reader.Close()
 			if err != nil {
@@ -105,6 +115,11 @@ func TestEmbeddingGzipFilesIntoApp(t *testing.T) {
 				// they are big files, no need to check for length here.
 				t.Fatalf("[%d] %s, expected body to look like: '%s...%s' but got '%s...%s'", i, url, expected[:40], expected[len(rawContents)-40:], got[:40], got[len(got)-40:])
 			}
-		}()
+		} else {
+			if expected, got := rawContents, rawBody; expected != got {
+				t.Fatalf("[%d] %s, expected body to look like: '%s...%s' but got '%s...%s'", i, url, expected[:40], expected[len(rawContents)-40:], got[:40], got[len(got)-40:])
+			}
+		}
+
 	}
 }