zipflow

zipflow is a library for elixir language that allows you to stream the zip archive while it is being created.

installation

the package can be installed as:

1. add zipflow to your list of dependencies in mix.exs:

   def deps do

    [{:zipflow, github: "dgvncsz0f/zipflow"}]

   end

the problem

erlang provides a :zip module that can be used to create a zip archive. however you can not use that to stream the zip file. using erlang's :zip module you only have the option to write to a file or entirely on memory.

this module solves that problem by streaming the contents of the zip file while it is being created.

example

this example writes a zip file to a file:

iex> File.open("/path/to/file", [:raw, :binary, :write], fn fh ->
...>   printer = & IO.binwrite(fh, &1)
...>   Zipflow.Stream.init
...>   |> Zipflow.Stream.entry(Zipflow.DataEntry.encode(printer, "foo/bar", "foobar"))
...>   |> Zipflow.Stream.flush(printer)
...> end)

Then you should have:

$ unzip -l /path/to/file
Archive:  example.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
        6  1980-00-00 00:00   foo/bar
---------                     -------
        6                     1 file

another example, this time archiving a file:

iex> File.open("/path/to/file", [:read, :raw, :binary], fn fh ->
...>   printer = & IO.binwrite(fh, &1)
...>   Zipflow.Stream.init
...>   |> Zipflow.Stream.entry(Zipflow.FileEntry.encode(printer, "foo/bar", fh))
...>   |> Zipflow.Stream.flush(printer)
...> end)

the FileEntry consumes the file in chunks so it has a low memory footprint. However, this is not a zip64 format so the maximum file size you can archive is 4G.

There is a script you can use for testing. It archives a directory:

$ mix escript.build
$ ./zipflow /tmp/zipflow.zip lib/bin
$ unzip -l /tmp/zipflow.zip
Archive:  /tmp/zipflow.zip
  Length      Date    Time    Name
---------  ---------- -----   ----
      301  1980-00-00 00:00   lib/bin/zip.ex
---------                     -------
      301                     1 file

todo

• encryption;
• compression;
• utf encoding;
• zip64 format;
• file/archive comments;
• store date/time correctly;
• support more than 2^16 files;

licence

BSD-3

contributors (thanks!)

• @feymartynov
• @nicholasjhenry