Unzip .zip file to a folder using :zip module

papakay

I’m trying to unzip a .zip file to a specific folder path:

:zip.unzip(zip_path, {cwd: "/tmp/test-extracted/"})

** (SyntaxError) test.exs:18: syntax error before: cwd
    (elixir) lib/code.ex:677: Code.require_file/2

Please how can i extract to a specified folder?

9 comments

#erlang #zip

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2018-07-02 19:53:22 UTC

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voughtdq

First, "/tmp/test-extracted" is a binary and Erlang mostly expects charlists. So binaries/strings will need to be converted to charlists first.

cwd = "/tmp/test-extracted/"
cwd = to_charlist(cwd)

Charlists can be represented by surrounding the string part with single quotes: 'charlist'. That can be easy to forget, so it’s better to use the sigil and do something like this: ~c'charlist'.

Second, Erlang opts are usually represented like this: [{:someopt, true}, :someotheropt, {:somethingelse, ~c'thing'}].

I haven’t tested, but this should be pretty close to the correct form:

:zip.unzip(zip_path, [{:cwd, ~c'/tmp/test-extracted/'}]) # also represented by [cwd: ~c'...']

Post #1

papakay

Thanks immensely @voughtdq for this clear explanation.

I have tried it as mentioned but i got bad match error

case :zip.unzip(~c'priv/static/files/document.zip', [{:cwd, ~c'/tmp/test-extracted/'}]) do
      {:ok, content} ->
        IO.inspect content
      {:error, error} ->
        IO.inspect(error)
    end

The logged output is

{:EXIT,
 {:function_clause,
  [
    {:zip, :get_unzip_opt,
     [
       {:cwd, '/tmp/test-extracted/'},
       {:unzip_opts, #Function<21.81481102/2 in :zip.get_unzip_options/2>,
        #Function<26.81481102/2 in :zip.get_input/1>,
        #Function<22.81481102/1 in :zip.get_unzip_options/2>, [:raw],
        #Function<23.81481102/1 in :zip.get_unzip_options/2>, []}
     ], [file: 'zip.erl', line: 538]},
    {:zip, :do_unzip, 2, [file: 'zip.erl', line: 364]},
    {:zip, :unzip, 2, [file: 'zip.erl', line: 358]},
    {RecordBank.Modules.Import, :unzip, 0,
     [file: 'lib/record_bank/modules/import.ex', line: 5]},
    {:erl_eval, :do_apply, 6, [file: 'erl_eval.erl', line: 670]},
    {:elixir, :eval_forms, 4, [file: 'src/elixir.erl', line: 233]},
    {IEx.Evaluator, :handle_eval, 5, [file: 'lib/iex/evaluator.ex', line: 250]},
    {IEx.Evaluator, :do_eval, 3, [file: 'lib/iex/evaluator.ex', line: 230]},
    {IEx.Evaluator, :eval, 3, [file: 'lib/iex/evaluator.ex', line: 208]},
    {IEx.Evaluator, :loop, 1, [file: 'lib/iex/evaluator.ex', line: 94]},
    {IEx.Evaluator, :init, 4, [file: 'lib/iex/evaluator.ex', line: 24]},
    {:proc_lib, :init_p_do_apply, 3, [file: 'proc_lib.erl', line: 247]}
  ]}}

Please what could be wrong?

Post #2

NobbZ

Similar code works for me:

iex(1)> :zip.unzip('zshrc.zip', [{:cwd, '~/tmp'}])
{:ok, ['~/tmp/.zshrc']}

Could you therefore please provie more information about your system, as which operating system you use, which OTP version, what tool originally created that zip file, etc.

Post #3

papakay

Thanks immensely @NobbZ.

I’m on macOS High Sierra (10.13.4)

Erlang/OTP 20 [erts-9.3.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]

The zip was downloaded from linkedin following the attachment below

Post #4

papakay

@NobbZ I forgot to also mention that the implementation is inside a Phoenix 1.3 application

Post #5

papakay

@NobbZ and @voughtdq thanks immensely for your contributions.

It’s now working! The problem was with the initial trailing slash. I removed the trailing slash preceding the directory name as below and it worked.

case :zip.unzip(~c'priv/static/files/document.zip', [{:cwd, ~c'tmp/test-extracted/'}]) do
      {:ok, content} ->
        IO.inspect content
      {:error, error} ->
        IO.inspect(error)
    end

Post #6