How to create a zip archive from files and directories in Go?

To create a zip archive from files and directories in Go, you can use the archive/zip package.

Here's an example program that creates a zip archive from a list of files and directories:

package main

import (
	"archive/zip"
	"io"
	"log"
	"os"
	"path/filepath"
)

func main() {
	// Create a new zip archive file named "archive.zip"
	zipfile, err := os.Create("archive.zip")
	if err != nil {
		log.Fatal(err)
	}
	defer zipfile.Close()

	// Create a new zip writer
	zipWriter := zip.NewWriter(zipfile)
	defer zipWriter.Close()

	// List of files and directories to add to the zip archive
	files := []string{"file.txt", "dir"}

	for _, file := range files {
		err := addFileToZip(zipWriter, file)
		if err != nil {
			log.Fatal(err)
		}
	}

	log.Println("Zip archive created successfully")
}

func addFileToZip(zipWriter *zip.Writer, file string) error {
	// Open the file for reading
	f, err := os.Open(file)
	if err != nil {
		return err
	}
	defer f.Close()

	// Get file info
	info, err := f.Stat()
	if err != nil {
		return err
	}

	// If the file is a directory, create a new directory header in the zip archive
	if info.IsDir() {
		header, err := zip.FileInfoHeader(info)
		if err != nil {
			return err
		}

		header.Name = file + "/"
		header.Method = zip.Deflate

		_, err = zipWriter.CreateHeader(header)
		if err != nil {
			return err
		}
	} else {
		// If the file is a regular file, create a new file header in the zip archive
		header, err := zip.FileInfoHeader(info)
		if err != nil {
			return err
		}

		header.Method = zip.Deflate

		writer, err := zipWriter.CreateHeader(header)
		if err != nil {
			return err
		}

		// Copy the file contents to the zip writer
		_, err = io.Copy(writer, f)
		if err != nil {
			return err
		}
	}

	return nil
}

In this example, we create a zip archive file named "archive.zip". We then iterate over a list of files and directories (files) and use the addFileToZip function to add each entry to the zip archive.

The addFileToZip function takes a zip writer, opens the file or directory, and adds it to the zip archive. If the entry is a directory, a new directory header is created in the zip archive. If the entry is a regular file, a new file header is created and the file contents are copied to the zip writer.