Creating ZIP files in Erlang

It’s pretty simple to create a ZIP file on disk.

Name = "foo.zip".
{ok, FileName} = zip:create(Name, ["foo.txt"]).

What if you want to create a ZIP file completely in memory? Also pretty simple:

Files = [{"foo.txt", <<"Contents of foo">>},
         {"bar.txt", <<"Contents of bar">>}].
{ok, {"mem", ZipBin}} = zip:create("mem", Files, [memory]).

Then, if you want to write that to a file:

file:write_file("foobar.zip", ZipBin).

Why would you want to do this? Well, you might be creating an escript:

escript:create('binary', [shebang, {archive, ZipBin}]).

Note that you need a module named for the script that exports a main function, as follows:

-export([main/1]).
main(Args) ->
    % Whatever.
    ok.

To clarify that last bit: if your script is named “awesome”, escript will look for an entry point named awesome:main/1.

This has the useful side-effect that you can copy (or symlink) the script to different names and use different entry points.