Improve caching, HTTP headers and URL handling (#3594)

* Fix relative URLs
* Improve login base URL and redirects
* Prevent duplicate customlocales requests
* Improve UI base URL handling
* Improve UI embedding
* Improve CSP header
* Add Cache-Control headers to all responses
* Improve CORS responses
* Improve authentication handler
* Add back media timestamp suffixes
* Fix default image handling
* Add default param to other image URLs

ui/ui.go

@@ -1,9 +1,46 @@
 package ui
 
-import "embed"
+import (
+	"embed"
+	"io/fs"
+	"runtime"
+)
 
 //go:embed v2.5/build
-var UIBox embed.FS
+var uiBox embed.FS
+var UIBox fs.FS
 
 //go:embed login
-var LoginUIBox embed.FS
+var loginUIBox embed.FS
+var LoginUIBox fs.FS
+
+func init() {
+	var err error
+	UIBox, err = fs.Sub(uiBox, "v2.5/build")
+	if err != nil {
+		panic(err)
+	}
+
+	LoginUIBox, err = fs.Sub(loginUIBox, "login")
+	if err != nil {
+		panic(err)
+	}
+}
+
+type faviconProvider struct{}
+
+var FaviconProvider = faviconProvider{}
+
+func (p *faviconProvider) GetFavicon() []byte {
+	if runtime.GOOS == "windows" {
+		ret, _ := fs.ReadFile(UIBox, "favicon.ico")
+		return ret
+	}
+
+	return p.GetFaviconPng()
+}
+
+func (p *faviconProvider) GetFaviconPng() []byte {
+	ret, _ := fs.ReadFile(UIBox, "favicon.png")
+	return ret
+}