server side favicon retrieving and caching

internal/homepage/homepage.go

@@ -1,5 +1,7 @@
 package homepage
 
+import "strings"
+
 type (
 	//nolint:recvcheck
 	Config   map[string]Category
@@ -8,7 +10,7 @@ type (
 	Item struct {
 		Show         bool           `json:"show"`
 		Name         string         `json:"name"` // display name
-		Icon         string         `json:"icon"`
+		Icon         *IconURL       `json:"icon"`
 		URL          string         `json:"url"` // alias + domain
 		Category     string         `json:"category"`
 		Description  string         `json:"description" aliases:"desc"`
@@ -22,7 +24,7 @@ type (
 
 func (item *Item) IsEmpty() bool {
 	return item == nil || (item.Name == "" &&
-		item.Icon == "" &&
+		item.Icon == nil &&
 		item.URL == "" &&
 		item.Category == "" &&
 		item.Description == "" &&
@@ -37,6 +39,13 @@ func (c *Config) Clear() {
 	*c = make(Config)
 }
 
+var cleanName = strings.NewReplacer(
+	" ", "-",
+	"_", "-",
+	"(", "",
+	")", "",
+)
+
 func (c Config) Add(item *Item) {
 	if c[item.Category] == nil {
 		c[item.Category] = make(Category, 0)

internal/homepage/icon_url.go

@@ -0,0 +1,46 @@
+package homepage
+
+import (
+	"strings"
+
+	E "github.com/yusing/go-proxy/internal/error"
+)
+
+type IconURL struct {
+	Value      string `json:"value"`
+	IsRelative bool   `json:"is_relative"`
+}
+
+const DashboardIconBaseURL = "https://cdn.jsdelivr.net/gh/walkxcode/dashboard-icons/"
+
+var ErrInvalidIconURL = E.New("invalid icon url")
+
+// Parse implements strutils.Parser.
+func (u *IconURL) Parse(v string) error {
+	if v == "" {
+		return ErrInvalidIconURL
+	}
+	slashIndex := strings.Index(v, "/")
+	if slashIndex == -1 {
+		return ErrInvalidIconURL
+	}
+	beforeSlash := v[:slashIndex]
+	switch beforeSlash {
+	case "http:", "https:":
+		u.Value = v
+		return nil
+	case "@target":
+		u.Value = v[slashIndex:]
+		u.IsRelative = true
+		return nil
+	case "png", "svg": // walkXCode Icons
+		u.Value = DashboardIconBaseURL + v
+		return nil
+	default:
+		return ErrInvalidIconURL
+	}
+}
+
+func (u *IconURL) String() string {
+	return u.Value
+}