Golang : Create zip/ePub file without compression(use Store algorithm)



Tags : golang zip epub no-compression

Problem :

You need to create zip file without compression. i.e just use the Store algorithm. For example, you are trying to create ePub file, which only uses Store algorithm.

Solution :

By default, Golang's archive/zip package uses the Store(no compression) algorithm. However, it is best not to assume that the default will always be the same after upgrade. To ensure that the zip/ePub file that are created with Store algorithm. Use the zip.CreateHeader() function with the following line :

 ...
 header, err := zip.FileInfoHeader(info)
 if err != nil {
 return err
 }
  header.Method = zip.Store // <<<----- here

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

or if you want to add more data to the header.

  writer, err := zipwriter.CreateHeader(&zip.FileHeader{
 Name: filename,
 Method: zip.Store,
  })

See full example on how to create zip file at : https://www.socketloop.com/tutorials/zip-compress-file-in-go

References :

https://www.socketloop.com/tutorials/zip-compress-file-in-go

http://golang.org/pkg/archive/zip/#Writer.CreateHeader

  See also : Golang : How to tell if a file is compressed either gzip or zip ?



Tags : golang zip epub no-compression

By Adam Ng

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