From 4f6e9e5c7c52b2daadbedff764419efed5a63254 Mon Sep 17 00:00:00 2001
From: Nazar Kanaev <nkanaev@live.com>
Date: Thu, 20 Aug 2020 00:10:30 +0100
Subject: [PATCH] bundle assets

---
 .gitignore         |  1 +
 bundle.go          | 81 ++++++++++++++++++++++++++++++++++++++++++++++
 server/handlers.go | 53 ++++++++++++++++++++++++++++--
 3 files changed, 132 insertions(+), 3 deletions(-)
 create mode 100644 bundle.go

diff --git a/.gitignore b/.gitignore
index 28a7e2e..200906b 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 yarr
 *.db
+server/assets_bundle.go
diff --git a/bundle.go b/bundle.go
new file mode 100644
index 0000000..f29b828
--- /dev/null
+++ b/bundle.go
@@ -0,0 +1,81 @@
+package main
+
+import (
+	"bytes"
+	"compress/gzip"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"io/ioutil"
+	"path/filepath"
+	"strings"
+	"text/template"
+)
+
+var code_template = `// autogenerated. do not edit!
+
+package server
+
+var assets_bundle = map[string]asset{
+	{{- range .}}
+	"{{.Name}}": {etag: "{{.Etag}}", body: "{{.Body}}"},
+	{{- end }}
+}
+
+func init() {
+	assets = assets_bundle
+}
+`
+
+type asset struct {
+	Name, Etag, Body string
+}
+
+func shasum(b []byte) string {
+	h := sha256.New()
+	h.Write(b)
+	return fmt.Sprintf("%x", h.Sum(nil))[:16]
+}
+
+func encode(b []byte) string {
+	var buf bytes.Buffer
+	zw := gzip.NewWriter(&buf)
+	zw.Write(b)
+	zw.Close()
+	return base64.StdEncoding.EncodeToString(buf.Bytes())
+}
+
+func main() {
+	outfile := "server/assets_bundle.go"
+	assets := make([]asset, 0)
+	filepatterns := []string{
+		"assets/index.html",
+		"assets/graphicarts/*.svg",
+		"assets/graphicarts/*.png",
+		"assets/javascripts/*.js",
+		"assets/stylesheets/*.css",
+		"assets/stylesheets/*.map",
+	}
+	fmt.Printf("%8s %8s %s\n", "original", "encoded", "filename")
+	for _, pattern := range filepatterns {
+		filenames, _ := filepath.Glob(pattern)
+		for _, filename := range filenames {
+			content, _ := ioutil.ReadFile(filename)
+			assets = append(assets, asset{
+				Name: strings.TrimPrefix(filename, "assets/"),
+				Etag: shasum(content),
+				Body: encode(content),
+			})
+			fmt.Printf(
+				"%8d %8d %s\n",
+				len(content),
+				len(assets[len(assets)-1].Body),
+				filename,
+			)
+		}
+	}
+	var buf bytes.Buffer
+	template := template.Must(template.New("code").Parse(code_template))
+	template.Execute(&buf, assets)
+	ioutil.WriteFile(outfile, buf.Bytes(), 0644)
+}
diff --git a/server/handlers.go b/server/handlers.go
index 11ee3be..26dcbf2 100644
--- a/server/handlers.go
+++ b/server/handlers.go
@@ -1,7 +1,10 @@
 package server
 
 import (
+	"bytes"
 	"encoding/json"
+	"encoding/base64"
+	"compress/gzip"
 	"fmt"
 	"github.com/nkanaev/yarr/storage"
 	"html"
@@ -37,6 +40,36 @@ var routes []Route = []Route{
 	p("/page", PageCrawlHandler),
 }
 
+type asset struct {
+	etag    string
+	body    string  // base64(gzip(content))
+	gzipped *[]byte
+	decoded *string
+}
+
+func (a *asset) gzip() *[]byte {
+	if a.gzipped == nil {
+		gzipped, _ := base64.StdEncoding.DecodeString(a.body)
+		a.gzipped = &gzipped
+	}
+	return a.gzipped
+}
+
+func (a *asset) text() *string {
+	if a.decoded == nil {
+		gzipped, _ := base64.StdEncoding.DecodeString(a.body)
+		reader, _ := gzip.NewReader(bytes.NewBuffer(gzipped))
+		decoded, _ := ioutil.ReadAll(reader)
+		reader.Close()
+
+		decoded_string := string(decoded)
+		a.decoded = &decoded_string
+	}
+	return a.decoded
+}
+
+var assets map[string]asset
+
 type FolderCreateForm struct {
 	Title string `json:"title"`
 }
@@ -58,6 +91,9 @@ type ItemUpdateForm struct {
 func IndexHandler(rw http.ResponseWriter, req *http.Request) {
 	t := template.Must(template.New("index.html").Delims("{%", "%}").Funcs(template.FuncMap{
 		"inline": func(svg string) template.HTML {
+			if asset, ok := assets["graphicarts/" + svg]; ok {
+				return template.HTML(*asset.text())
+			}
 			content, _ := ioutil.ReadFile("assets/graphicarts/" + svg)
 			return template.HTML(content)
 		},
@@ -67,14 +103,25 @@ func IndexHandler(rw http.ResponseWriter, req *http.Request) {
 }
 
 func StaticHandler(rw http.ResponseWriter, req *http.Request) {
-	path := "assets/" + Vars(req)["path"]
-	f, err := os.Open(path)
+	path := Vars(req)["path"]
+	ctype := mime.TypeByExtension(filepath.Ext(path))
+
+	if assets != nil {
+		if asset, ok := assets[path]; ok {
+			rw.Header().Set("Content-Type", ctype)
+			rw.Header().Set("Content-Encoding", "gzip")
+			rw.Header().Set("Etag", asset.etag)
+			rw.Write(*asset.gzip())
+		}
+	}
+
+	f, err := os.Open("assets/" + path)
 	if err != nil {
 		rw.WriteHeader(http.StatusNotFound)
 		return
 	}
 	defer f.Close()
-	rw.Header().Set("Content-Type", mime.TypeByExtension(filepath.Ext(path)))
+	rw.Header().Set("Content-Type", ctype)
 	io.Copy(rw, f)
 }