epub folder zip -- one file must not be compressed

[kerflooey]

At http://idpf.org/epub/30/spec/epub30-ocf.html under “3.3 OCF ZIP Container Media Type Identification” it says that the “mimetype file additionally must be neither compressed nor encrypted, and there must not be an extra field in its ZIP header.”

1. Is there a way to zip a folder but specify that this one file not be compressed? Or 2) Is there a way to zip a folder without compressing anything, but still have it be a valid zip (epub) file? Or 3) Could I zip the folder normally and then replace the compressed mimetype file with an uncompressed version? And 4) WTF? Why would they require a non-compressed file in a compressed folder? That seems strange to me, as I’ve never run into such a requirement before.

Thanks for any help or insight on this. My goal is to easily zip a folder and change its extension from “.zip” to “.epub” via Applescript to get a valid epub file.

[McUsrII]

Hello.

Please see man zip

From the man page:

@zip.1

–suffixes suffixes

•          Do not attempt to compress files named with the given suffixes.  Such files are simply
  

•          stored (0% compression) in the output zip file, so that zip  doesn't  waste  its  time
  

•          trying  to  compress them.  The suffixes are separated by either colons or semicolons.
           For example:
  
                  zip -rn .Z:.zip:.tiff:.gif:.snd  foo foo
  

-#
(-0, -1, -2, -3, -4, -5, -6, -7, -8, -9)

•          Regulate  the  speed of compression using the specified digit #, [b]where -0 indicates no
  

•          compression (store all files)[/b], -1 indicates the fastest compression speed  (less  com-
  

•          pression) and -9 indicates the slowest compression speed (optimal compression, ignores
  

•          the suffix list). The default compression level is -6.
  

•          Though still being worked, the intention is  this  setting  will  control  compression
  

•          speed for all compression methods.  Currently only deflation is controlled.
  

-Z cm

•   --compression-method cm
  

•          Set the default compression method.  Currently the main methods supported by  zip  are
  

•          store and deflate.  Compression method can be set to:
  

•          store  -  Setting  the compression method to store forces zip to store entries with no
  

•          compression.  This is generally faster than compressing entries,  but  results  in  no
  

•          space savings.  This is the same as using -0 (compression level zero).
  
           deflate  - This is the default method for zip.  If zip determines that storing is bet-
           ter than deflation, the entry will be stored instead.
  

•          bzip2 - If bzip2 support is compiled in, this compression method also  becomes  avail-
  

•          able.  Only some modern unzips currently support the bzip2 compression method, so test
  

•          the unzip you will be using before relying on archives using this method  (compression
           method 12).
  

•          For example, to add bar.c to archive foo using bzip2 compression:
  
                  zip -Z bzip2 foo bar.c
  

•          The compression method can be abbreviated:
  
                  zip -Zb foo bar.c
  

Edit
Added the -Z option to the quote.
HTH

[kerflooey]

Thanks. The mimetype file has no extension to filter by, so I tried:

set fn to “HTML5_CSS3_Book.zip”
set dn to “HTML5_CSS3_Book”
do shell script “zip -r -0 ~/Desktop/” & fn & " " & “~/Desktop/” & dn

This zipped the folder and the result said 0% compression on all files, but the byte count shown in the Finder Info Window differed for the folder and the zip that I made. But it seems like this would probably work.

[McUsrII]

I hope it does!

The difference may be that the zip program counts 1k as 1024 while the Finder counts 1k as 1000.

I would test it carefully anyhow if I were you.