feat: add ZipAppendEntry (#113)

fileutil/file.go

@@ -208,7 +208,11 @@ func Zip(fpath string, destPath string) error {
 	archive := zip.NewWriter(zipFile)
 	defer archive.Close()
 
-	err = filepath.Walk(fpath, func(path string, info os.FileInfo, err error) error {
+	return addFileToArchive(fpath, archive)
+}
+
+func addFileToArchive(fpath string, archive *zip.Writer) error {
+	err := filepath.Walk(fpath, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
 			return err
 		}
@@ -224,32 +228,22 @@ func Zip(fpath string, destPath string) error {
 			header.Name += "/"
 		} else {
 			header.Method = zip.Deflate
-		}
-
-		writer, err := archive.CreateHeader(header)
-		if err != nil {
-			return err
-		}
-
-		if !info.IsDir() {
+			writer, err := archive.CreateHeader(header)
+			if err != nil {
+				return err
+			}
 			file, err := os.Open(path)
 			if err != nil {
 				return err
 			}
 			defer file.Close()
-			_, err = io.Copy(writer, file)
-			if err != nil {
+			if _, err := io.Copy(writer, file); err != nil {
 				return err
 			}
 		}
 		return nil
 	})
-
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 // UnZip unzip the file and save it to destPath.
@@ -302,6 +296,64 @@ func UnZip(zipFile string, destPath string) error {
 	return nil
 }
 
+// ZipAppendEntry append a single file or directory by fpath to an existing zip file.
+// Play: https://go.dev/play/p/cxvaT8TRNQp
+func ZipAppendEntry(fpath string, destPath string) error {
+	tempFile, err := os.CreateTemp("", "temp.zip")
+	if err != nil {
+		return err
+	}
+	defer os.Remove(tempFile.Name())
+
+	zipReader, err := zip.OpenReader(destPath)
+	if err != nil {
+		return err
+	}
+
+	archive := zip.NewWriter(tempFile)
+
+	for _, zipItem := range zipReader.File {
+		zipItemReader, err := zipItem.Open()
+		if err != nil {
+			return err
+		}
+		header, err := zip.FileInfoHeader(zipItem.FileInfo())
+		if err != nil {
+			return err
+		}
+		header.Name = zipItem.Name
+		targetItem, err := archive.CreateHeader(header)
+		if err != nil {
+			return err
+		}
+		_, err = io.Copy(targetItem, zipItemReader)
+		if err != nil {
+			return err
+		}
+	}
+
+	err = addFileToArchive(fpath, archive)
+
+	if err != nil {
+		return err
+	}
+
+	err = zipReader.Close()
+	if err != nil {
+		return err
+	}
+	err = archive.Close()
+	if err != nil {
+		return err
+	}
+	err = tempFile.Close()
+	if err != nil {
+		return err
+	}
+
+	return CopyFile(tempFile.Name(), destPath)
+}
+
 func safeFilepathJoin(path1, path2 string) (string, error) {
 	relPath, err := filepath.Rel(".", path2)
 	if err != nil || strings.HasPrefix(relPath, "..") {