Zipc v0.2.0

Zipc is an in-memory ZIP archive and deflate compression codec. Other compression formats in ZIP archives can be supported by using third-party libraries.

See the quick start and the limitations.

Library zipc

• Zipc ZIP archives.
• Zipc_deflate Deflate and zlib compressed data formats.

Quick start

These convenience functions to read and write files or standard streams are used below.

Reads stdin or a file's bytes to a string.

let read_file file =
  let read file ic = try Ok (In_channel.input_all ic) with
  | Sys_error e -> Error (Printf.sprintf "%s: %s" file e)
  in
  let binary_stdin () = In_channel.set_binary_mode In_channel.stdin true in
  try match file with
  | "-" -> binary_stdin (); read file In_channel.stdin
  | file -> In_channel.with_open_bin file (read file)
  with Sys_error e -> Error e

Writes a string's bytes to stdout or a file.

let write_file file s =
  let write file s oc = try Ok (Out_channel.output_string oc s) with
  | Sys_error e -> Error (Printf.sprintf "%s: %s" file e)
  in
  let binary_stdout () = Out_channel.(set_binary_mode stdout true) in
  try match file with
  | "-" -> binary_stdout (); write file s Out_channel.stdout
  | file -> Out_channel.with_open_bin file (write file s)
  with Sys_error e -> Error e

Decode

This extracts the data of a file named path in a ZIP archive read from the file archive:

let unzip_path ~path ~archive =
  let ( let* ) = Result.bind in
  let file_error file msg = Printf.sprintf "%s: %s" file msg in
  let* s = read_file archive in
  Result.map_error (file_error archive) @@
  let* z = Zipc.of_binary_string s in
  Result.map_error (file_error path) @@
  match Option.map Zipc.Member.kind (Zipc.find path z) with
  | None -> Error "No such path"
  | Some Zipc.Member.Dir -> Error "Is a directory"
  | Some Zipc.Member.File file ->
      let* data = Zipc.File.to_binary_string file in
      Ok (Zipc.Fpath.sanitize path, data)

Encode

This function reads the file file, adds it under its basename to an empty ZIP archive and writes the result to the file archive.

let zip_file ?(compress = true) ~file ~archive () =
  let ( let* ) = Result.bind in
  let file_error file msg = Printf.sprintf "%s: %s" file msg in
  let* s = read_file file in
  let* m =
    Result.map_error (file_error file) @@
    let path = Filename.basename file in
    let* file = match compress with
    | true -> Zipc.File.deflate_of_binary_string s
    | false -> Zipc.File.stored_of_binary_string s
    in
    Zipc.Member.make ~path (Zipc.Member.File file)
  in
  let* s = Zipc.to_binary_string (Zipc.add m Zipc.empty) in
  write_file archive s

Note that in this example the actual permissions and modification time of file are not preserved in the archive, we rely on defaults. A bit more work with the Unix module would be needed. See for example the source of the zipc tool in the distribution.

If you would like to see js_of_ocaml examples look at the test directory in the development repository of the library.