feat(api): add in-memory cache for index endpoint

go.mod

@@ -15,6 +15,7 @@ require (
 	github.com/markbates/pkger v0.17.1
 	github.com/microcosm-cc/bluemonday v1.0.15
 	github.com/ohler55/ojg v1.10.0
+	github.com/patrickmn/go-cache v2.1.0+incompatible
 	github.com/russross/blackfriday/v2 v2.0.1
 	github.com/userstyles-world/go-chart/v2 v2.4.1
 	github.com/vednoc/go-usercss-parser v0.9.2

go.sum

@@ -317,6 +317,8 @@ github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1Cpa
 github.com/onsi/gomega v1.7.1/go.mod h1:XdKZgCCFLUoM/7CFJVPcG8C1xQ1AJ0vpAezJrB7JYyY=
 github.com/onsi/gomega v1.9.0/go.mod h1:Ho0h+IUsWyvy1OpqCwxlQ/21gkhVunqlU8fDGcoTdcA=
 github.com/pascaldekloe/goe v0.0.0-20180627143212-57f6aae5913c/go.mod h1:lzWF7FIEvWOWxwDKqyGYQf6ZUaNfKdP144TG7ZOy1lc=
+github.com/patrickmn/go-cache v2.1.0+incompatible h1:HRMgzkcYKYpi3C8ajMPV8OFXaaRUnok+kx1WdO15EQc=
+github.com/patrickmn/go-cache v2.1.0+incompatible/go.mod h1:3Qf8kWWT7OJRJbdiICTKqZju1ZixQ/KpMGzzAfe6+WQ=
 github.com/pborman/uuid v1.2.0/go.mod h1:X/NO0urCmaxf9VXbdlT7C2Yzkj2IKimNn4k+gtPdI/k=
 github.com/pelletier/go-toml v1.2.0/go.mod h1:5z9KED0ma1S8pY6P1sdut58dfprrGBbd/94hg7ilaic=
 github.com/phayes/checkstyle v0.0.0-20170904204023-bfd46e6a821d/go.mod h1:3OzsM7FXDQlpCiw2j81fOmAwQLnZnLGXVKUzeKQXIAw=

handlers/api/index.go

@@ -3,8 +3,10 @@ package api
 import (
 	"fmt"
 	"strings"
+	"time"
 
 	"github.com/gofiber/fiber/v2"
+	"github.com/patrickmn/go-cache"
 
 	"userstyles.world/models"
 )
@@ -20,6 +22,8 @@ type USoFormat struct {
 	ID             uint   `json:"i"`
 }
 
+var mem = cache.New(5*time.Minute, 10*time.Minute)
+
 func convertToUSoFormat(s models.APIStyle) USoFormat {
 	id := fmt.Sprintf("%d", s.ID) // Convert uint to string.
 
@@ -71,13 +75,25 @@ func GetStyleIndex(c *fiber.Ctx) error {
 
 	// Used by Stylus integration.
 	if c.Params("format") == "uso-format" {
-		formattedStyles := make([]USoFormat, len(*styles))
-		for i, style := range *styles {
-			formattedStyles[i] = convertToUSoFormat(style)
+	Convert:
+		cached, found := mem.Get("index")
+		if !found {
+			formatted := make([]USoFormat, len(*styles))
+			for i, style := range *styles {
+				formatted[i] = convertToUSoFormat(style)
+			}
+
+			mem.Set("index", formatted, 10*time.Minute)
+			goto Convert
+		}
+
+		index, ok := cached.([]USoFormat)
+		if !ok {
+			goto Convert
 		}
 
 		return c.JSON(fiber.Map{
-			"data": formattedStyles,
+			"data": index,
 		})
 	}