feat(backend): serve static frontend files

backend/api/static.go

@@ -0,0 +1,26 @@
+package api
+
+import (
+	"embed"
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+func SPAMiddleware(fs embed.FS, prefix string, notFoundPath string) gin.HandlerFunc {
+	fileServer := http.FileServerFS(fs)
+
+	return func(c *gin.Context) {
+		if strings.HasPrefix(c.Request.URL.Path, "/api/") {
+			c.Next()
+			return
+		}
+		c.Request.URL.Path = prefix + c.Request.URL.Path
+		_, err := fs.Open(c.Request.URL.Path)
+		if err != nil {
+			c.Request.URL.Path = prefix + notFoundPath
+		}
+		fileServer.ServeHTTP(c.Writer, c.Request)
+	}
+}