add caching and change the layout a bit

go.mod

@@ -8,6 +8,7 @@ require (
 )
 
 require (
+	github.com/allegro/bigcache/v3 v3.0.2 // indirect
 	github.com/andybalholm/cascadia v1.3.1 // indirect
 	golang.org/x/net v0.0.0-20210916014120-12bc252f5db8 // indirect
 )

go.sum

@@ -1,5 +1,7 @@
 github.com/PuerkitoBio/goquery v1.8.0 h1:PJTF7AmFCFKk1N6V6jmKfrNH9tV5pNE6lZMkG0gta/U=
 github.com/PuerkitoBio/goquery v1.8.0/go.mod h1:ypIiRMtY7COPGk+I/YbZLbxsxn9g5ejnI2HSMtkjZvI=
+github.com/allegro/bigcache/v3 v3.0.2 h1:AKZCw+5eAaVyNTBmI2fgyPVJhHkdWder3O9IrprcQfI=
+github.com/allegro/bigcache/v3 v3.0.2/go.mod h1:aPyh7jEvrog9zAwx5N7+JUQX5dZTSGpxF1LAR4dr35I=
 github.com/andybalholm/cascadia v1.3.1 h1:nhxRkql1kdYCc8Snf7D5/D3spOX+dBgjA6u8x004T2c=
 github.com/andybalholm/cascadia v1.3.1/go.mod h1:R4bJ1UQfqADjvDa4P6HZHLh/3OxWWEqc0Sk8XGwHqvA=
 github.com/gorilla/mux v1.8.0 h1:i40aqfkR1h2SlN9hojwV5ZA91wcXFOvkdNIeFDP5koI=

lyrics.go

@@ -49,6 +49,11 @@ func (s *song) parse(doc *goquery.Document) {
 func lyricsHandler(w http.ResponseWriter, r *http.Request) {
 	id := mux.Vars(r)["id"]
 
+	if data, err := getCache(id); err == nil {
+		render(w, data)
+		return
+	}
+
 	url := fmt.Sprintf("https://genius.com/%s-lyrics", id)
 	resp, err := http.Get(url)
 	if err != nil {
@@ -78,4 +83,5 @@ func lyricsHandler(w http.ResponseWriter, r *http.Request) {
 	}
 
 	t.Execute(w, s)
+	setCache(id, s)
 }

main.go

@@ -2,32 +2,27 @@ package main
 
 import (
 	"fmt"
-	"log"
 	"net"
 	"net/http"
 	"os"
 	"strconv"
 	"time"
 
+	"github.com/allegro/bigcache/v3"
 	"github.com/gorilla/mux"
 )
 
-func fatal(err any) {
-	log.Fatalf("[ERR] %s\n", err)
-}
-
-func info(s string) {
-	log.Printf("[INFO] %s\n", s)
-}
-
-func write(w http.ResponseWriter, status int, data []byte) {
-	w.WriteHeader(status)
-	w.Write(data)
-}
-
 func main() {
+	c, err := bigcache.NewBigCache(bigcache.DefaultConfig(time.Hour * 2))
+	if err != nil {
+		fatal("can't initialize caching")
+	}
+	cache = c
+
 	r := mux.NewRouter()
 
+	r.Use(securityHeaders)
+
 	r.HandleFunc("/{id}-lyrics", lyricsHandler)
 	r.PathPrefix("/static/").Handler(http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
 

static/script.js

@@ -1,4 +1,4 @@
-document.querySelectorAll("#lyrics > a").forEach(item => {
+document.querySelectorAll("#lyrics a").forEach(item => {
 	item.addEventListener("click", getAnnotation)
 })
 

static/style.css

@@ -45,10 +45,6 @@ body {
 }
 
 #lyrics {
-	position: absolute;
-	left: 50%;
-	transform: translateX(-50%);
-	padding: 1rem 0;
 	color: #171717;
 	line-height: 2.5rem;
 }
@@ -58,6 +54,10 @@ body {
 	color: inherit;
 }
 
+#lyrics a:hover {
+	background-color: #ccc;
+}
+
 #nav {
 	font-size: 2.5rem;
 	text-align: center;
@@ -76,24 +76,30 @@ a {
 #metadata {
 	display: flex;
 	flex-direction: column;
-	align-items: center;
 	gap: 0.5rem;
-	padding: 1rem;
+	text-align: center;
 }
 
 #metadata h1 {
-	font-size: 2.2rem;
+	font-size: 2rem;
 	color: #171717;
 }
 
 #metadata h2 {
-	font-size: 1.5rem;
+	font-size: 1.4rem;
 	color: #1E1E1E;
-	text-transform: uppercase;
 	font-weight: 500;
 }
 
 #metadata > img {
 	width: 20rem;
 	border-radius: 3px;
+	box-shadow: 0 1px 1px #ddd;
+}
+
+#container {
+	display: flex;
+	padding: 2rem;
+	gap: 5rem;
+	justify-content: center;
 }

utils.go

@@ -0,0 +1,73 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+	"path"
+	"text/template"
+
+	"github.com/allegro/bigcache/v3"
+)
+
+var cache *bigcache.BigCache
+
+func setCache(key string, entry any) error {
+	data, err := json.Marshal(&entry)
+	if err != nil {
+		return err
+	}
+
+	return cache.Set(key, data)
+}
+
+func getCache(key string) (any, error) {
+	data, err := cache.Get(key)
+	if err != nil {
+		return nil, err
+	}
+
+	var decoded any
+
+	if err = json.Unmarshal(data, &decoded); err != nil {
+		return nil, err
+	}
+
+	return decoded, nil
+}
+
+func fatal(err any) {
+	log.Fatalf("[ERR] %s\n", err)
+}
+
+func info(s string) {
+	log.Printf("[INFO] %s\n", s)
+}
+
+func write(w http.ResponseWriter, status int, data []byte) {
+	w.WriteHeader(status)
+	w.Write(data)
+}
+
+func securityHeaders(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		csp := "default-src 'self'; script-src 'self'; style-src 'self'; img-src 'self' images.genius.com; object-src 'none'"
+		w.Header().Add("content-security-policy", csp)
+		w.Header().Add("referrer-policy", "no-referrer")
+		w.Header().Add("x-content-type-options", "nosniff")
+		next.ServeHTTP(w, r)
+	})
+}
+
+func render(w http.ResponseWriter, data any) {
+	t, err := template.ParseFiles(path.Join("views/lyrics.tmpl"))
+	if err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+
+	if err = t.Execute(w, data); err != nil {
+		w.WriteHeader(http.StatusInternalServerError)
+		return
+	}
+}

views/lyrics.tmpl

@@ -8,11 +8,13 @@
 	</head>
 	<body>
 		<h1 id="nav">DUMB</h1>
+		<div id="container">
 			<div id="metadata">
 				<img src="{{.Image}}"/>
 				<h2>{{.Artist}}</h2>
 				<h1>{{.Title}}</h1>
 			</div>
 			<div id="lyrics">{{.Lyrics}}</div>
+		</div>
 	</body>
 </html>