141 lines
3.1 KiB
Go
141 lines
3.1 KiB
Go
package archive
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import (
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"archive/tar"
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"compress/gzip"
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"fmt"
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"io"
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"log/slog"
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"os"
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"path/filepath"
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)
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const (
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// Tune these to your app’s needs
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maxCompressedUpload = 500 << 20 // 500 MiB compressed
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maxUncompressedOutput = 1000 << 20 // 100 MiB after inflate
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)
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func Untar(file io.Reader, path string) error {
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gzr, err := gzip.NewReader(file)
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if err != nil {
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return err
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}
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defer gzr.Close()
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tr := tar.NewReader(gzr)
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for {
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header, err := tr.Next()
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switch {
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// if no more files are found return
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case err == io.EOF:
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return nil
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// return any other error
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case err != nil:
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return err
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// if the header is nil, just skip it (not sure how this happens)
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case header == nil:
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continue
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}
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// the target location where the dir/file should be created
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target := filepath.Clean(filepath.Join(path, filepath.Clean(header.Name)))
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// the following switch could also be done using fi.Mode(), not sure if there
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// a benefit of using one vs. the other.
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// fi := header.FileInfo()
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// check the file type
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switch header.Typeflag {
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// if its a dir and it doesn't exist create it
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case tar.TypeDir:
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if _, err := os.Stat(target); err != nil {
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if err := os.MkdirAll(target, 0740); err != nil {
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return err
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}
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}
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// if it's a file create it
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case tar.TypeReg:
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f, err := os.OpenFile(target, os.O_CREATE|os.O_RDWR, header.FileInfo().Mode())
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if err != nil {
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return err
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}
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limited := &io.LimitedReader{R: gzr, N: maxUncompressedOutput}
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// copy over contents
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if _, err := io.Copy(f, limited); err != nil {
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return err
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}
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// manually close here after each file operation; defering would cause each file close
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// to wait until all operations have completed.
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if err := f.Close(); err != nil {
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slog.Error("failed to close file", "err", err)
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}
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if limited.N == 0 {
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// Limit exhausted → likely bomb
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return fmt.Errorf("payload too large after decompression")
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}
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}
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}
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}
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func Tar(file io.Writer, root string) error {
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gw := gzip.NewWriter(file)
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defer gw.Close()
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tw := tar.NewWriter(gw)
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defer tw.Close()
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// Walk again to add files
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err := filepath.Walk(root, func(path string, info os.FileInfo, walkErr error) error {
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if walkErr != nil {
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return fmt.Errorf("failed to walk through the directory: %w", walkErr)
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}
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relpath, err := filepath.Rel(root, path)
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if err != nil {
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return fmt.Errorf("failed to make relative path: %w", err)
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}
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// Create tar header
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header, err := tar.FileInfoHeader(info, path)
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if err != nil {
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return fmt.Errorf("failed to make file info header: %w", err)
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}
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header.Name = relpath
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if err := tw.WriteHeader(header); err != nil {
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return fmt.Errorf("failed to write header: %w", err)
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}
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if !info.Mode().IsRegular() {
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return nil
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}
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file, err := os.Open(filepath.Clean(path))
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if err != nil {
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return fmt.Errorf("failed to open file: %w", err)
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}
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defer file.Close()
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if _, err := io.Copy(tw, file); err != nil {
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return fmt.Errorf("failed to copy file: %w", err)
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}
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return nil
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})
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if err != nil {
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return fmt.Errorf("writing tar entries: %w", err)
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}
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return nil
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}
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