fileio: create parent dirs before writing file

Author: nalgeon

internal/fileio/fileio.go

@@ -71,9 +71,18 @@ func ReadJson[T any](path string) (T, error) {
 }
 
 // WriteFile writes the file to disk.
+// If the path directories do not exist, creates them.
 // The content can be text or binary (encoded as a data URL),
 // e.g. data:application/octet-stream;base64,MTIz
 func WriteFile(path, content string, perm fs.FileMode) (err error) {
+	// create parent directories if needed
+	dir := filepath.Dir(path)
+	err = os.MkdirAll(dir, 0755)
+	if err != nil {
+		return err
+	}
+
+	// write file content
 	var data []byte
 	if !strings.HasPrefix(content, "data:") {
 		// text file

internal/fileio/fileio_test.go

@@ -114,6 +114,16 @@ func TestWriteFile(t *testing.T) {
 	be.Err(t, err, nil)
 	defer func() { _ = os.RemoveAll(dir) }()
 
+	t.Run("create nested dirs", func(t *testing.T) {
+		path := filepath.Join(dir, "a/b/c/file.txt")
+		err = WriteFile(path, "hello", 0444)
+		be.Err(t, err, nil)
+		got, err := os.ReadFile(path)
+		be.Err(t, err, nil)
+		want := []byte("hello")
+		be.Equal(t, got, want)
+	})
+
 	t.Run("text", func(t *testing.T) {
 		path := filepath.Join(dir, "data.txt")
 		err = WriteFile(path, "hello", 0444)