Add common routines and theme dojigger

cmd/mothd/common.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"path/filepath"
+	"strings"
+)
+
+func MothPath(base string, parts ...string) string {
+	path := filepath.Clean(filepath.Join(parts...))
+	parts = filepath.SplitList(path)
+	for i, part := range parts {
+		part = strings.TrimLeft(part, "./\\:")
+		parts[i] = part
+	}
+	parts = append([]string{base}, parts...)
+	path = filepath.Join(parts...)
+	path = filepath.Clean(path)
+	return path
+}

cmd/mothd/theme.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"net/http"
+	"os"
+	"strings"
+)
+
+type Theme struct {
+	ThemeDir string
+}
+
+func NewTheme(themeDir string) *Theme {
+	return &Theme{
+		ThemeDir: themeDir,
+	}
+}
+
+func (t *Theme) path(parts ...string) string {
+	return MothPath(t.ThemeDir, parts...)
+}
+
+func (t *Theme) staticHandler(w http.ResponseWriter, req *http.Request) {
+	path := req.URL.Path
+	if strings.Contains(path, "/.") {
+		http.Error(w, "Invalid URL path", http.StatusBadRequest)
+		return
+	}
+	if path == "/" {
+		path = "/index.html"
+	}
+
+	f, err := os.Open(t.path(path))
+	if err != nil {
+		http.NotFound(w, req)
+		return
+	}
+	defer f.Close()
+
+	d, err := f.Stat()
+	if err != nil {
+		http.NotFound(w, req)
+		return
+	}
+
+	http.ServeContent(w, req, path, d.ModTime(), f)
+}