This:

/app # iex -S mix
Erlang/OTP 21 [erts-10.3.5.1] [source] [64-bit] [smp:4:4] [ds:4:4:10] [async-threads:1] [hipe]

Interactive Elixir (1.7.4) - press Ctrl+C to exit (type h() ENTER for help)
iex(1)> defmodule TestStruct do
...(1)>   defstruct field_one: nil,
...(1)>             field_two: nil,
...(1)>             field_three: nil,
...(1)>             field_four: nil
...(1)>   use ExConstructor
...(1)> end
{:module, TestStruct,
 <<70, 79, 82, 49, 0, 0, 7, 224, 66, 69, 65, 77, 65, 116, 85, 56, 0, 0, 0, 249,
   0, 0, 0, 23, 17, 69, 108, 105, 120, 105, 114, 46, 84, 101, 115, 116, 83, 116,
   114, 117, 99, 116, 8, 95, 95, 105, 110, ...>>, :ok}
iex(2)> 
nil
iex(3)> TestStruct.new(%{"field_one" => "a", "fieldTwo" => "b", :field_three => "c", :FieldFour => "d"})
%TestStruct{field_four: nil, field_one: "a", field_three: "c", field_two: "b"}

Expect: %TestStruct{field_one: "a", field_two: "b", field_three: "c", field_four: "d"}

Last commit was quite one year ago ?

Kernel.struct!/2 is stricter (see docs), which will prevent the ignorance of @enforce_keys and prevent invalid struct keys being passed.

If you want some code to do the two checks independently, you could add something like this:

  use ExConstructor, check_enforce_keys: true, check_no_invalid_args: true

  ...

  # pass @enforce_keys as 2nd param
  def check_enforce_keys(args, enforce_keys) do
    arg_keys =
      args
      |> Map.new
      |> Map.keys
      |> MapSet.new
    required_keys = enforce_keys |> MapSet.new

    if not MapSet.subset?(required_keys, arg_keys) do
      raise(
        ArgumentError,
        "Requires keys #{required_keys |> Enum.to_list |> inspect} "
        <> "but only #{arg_keys |> Enum.to_list |> inspect} "
        <> "were given"
      )
    end
  end

  def check_no_invalid_args(args, module) do
    arg_keys =
      args
      |> Map.new
      |> Map.keys
      |> MapSet.new
    valid_keys =
      module
      |> struct([])
      |> Map.from_struct
      |> Map.keys
      |> MapSet.new

    if not MapSet.subset?(arg_keys, valid_keys) do
      raise(
        KeyError,
        "Allowed keys are #{valid_keys |> Enum.to_list |> inspect} "
        <> "but #{arg_keys |> Enum.to_list |> inspect} "
        <> "were given"
      )
    end
  end

It would be a useful extension to be able to produce maps with keys cased in one specific flavour.

One example use would be to produce Javascript-style camelCase API responses while maintaining structs and maps internally in snake_case.

Hi,

the doc say to put the use ExConstructor after the struct creation, but i've put it before and it's seams to work the same. Am i miss something? I'm running elixir 1.15.

The example of TestStruct say that field_four sould be correctlly filled with d, but it seams not working.

warning: negative steps are not supported in String.slice/2, pass 1..-1//1 instead
(elixir 1.16.0) lib/string.ex:2368: String.slice/2

The change is as I can understand and conclude from testing backwards compatible.

iex(5)> TestStruct.new(%{"field_one" => "a", "fieldTwo" => "b", :field_Three => "c", :fieldFour => "d"})
%TestStruct{field_four: "d", field_one: "a", field_three: 3, field_two: "b"}

where does it get the 3 from?

I tried running this in my escript and go this error. Are there some dependencies I'm missing?

** (UndefinedFunctionError) undefined function Mix.Utils.underscore/1 (module Mix.Utils is not available)
    Mix.Utils.underscore("field_four")
...

defmodule Bot.Mixfile do
  use Mix.Project

  def project do
    [
      app: :bot,
      version: "0.0.1",
      elixir: "~> 1.2",
      escript: [main_module: Bot],
      build_embedded: Mix.env == :prod,
      start_permanent: Mix.env == :prod,
      deps: deps,
      default_task: "bot.run"
    ]
  end

  def application do
    [
      applications: [
        :logger,
        :nadia,
        :httpoison, :poison,
        :tzdata,
        :exconstructor
      ]
    ]
  end

  defp deps do
    [{:nadia, git: "https://github.com/zhyu/nadia"},
     {:httpoison, "~> 0.8.0"},
     {:poison, "~> 1.5.0"},
     {:tzdata, "== 0.1.8", override: true},
     {:timex, git: "https://github.com/bitwalker/timex"},
     {:exconstructor, "~> 0.2.0"}
    ]
  end
end

Description

Problem parsing acronyms which are entirely uppercase within a string. Acronyms seem to be quite common is apis returning json.

What I mean by acronyms:
ImageID --> image_id, IPAddress --> ip_address

Example

  defmodule Identity.Endpoint do
    defstruct [:admin_url, :region, :internal_url, :id, :public_url]
    use ExConstructor
  end

Identity.Endpoint.new(
  %{
  "adminURL" => "adminURL", 
  "id" => "id", 
  "internalURL" => "internalURL", 
  "publicURL" => "publicURL",
   "region" => "region"
  }
)

Returns

%Identity.Endpoint{
  admin_url: nil, 
  id: "id", 
  internal_url: nil, 
  public_url: nil,
  region: "region"
}

Potential Solution:

Screen for acronyms. Pull request on its way. 🔨

Tracked it down to the line underneath the unquote. Any ideas?

  def unquote(constructor_name)(map_or_kwlist, opts \\ []) do
          ExConstructor.populate_struct(
            %__MODULE__{},
            map_or_kwlist,
            Keyword.merge(@exconstructor_default_options, opts)
          )

  defmodule Point do
    @enforce_keys [:x, :y]
    defstruct [:x, :y, :z]

    use ExConstructor
  end

Error when defining module:

** (ArgumentError) the following keys must also be given when building struct ExConstructorValidatorTest.Point: [:x, :y]

Could be caused by this:

%__MODULE__{},

Perhaps create struct with Kernel.struct/2 which does not check @enforce_keys like %_{} and Kernel.struct!/2 do:

Kernel.struct(__MODULE__, [])

@gamache hi! First of all, thanks for the library. Maybe I am mistaken, however since we are:

https://github.com/appcues/exconstructor/blob/master/lib/exconstructor.ex#L158-L159 from a newly generated string from Macro.underscore/1 and Macro.camelize/1, wouldn't that be new strings associated with newly created atoms?

For example:

iex(141)> Regex.named_captures(~r/index_table:atom_tab\n*\n.*\n.*\nentries:(?<atoms>.*)/m, :erlang.system_info(:info))
%{"atoms" => " 20963"}
iex(142)> camelized = Macro.camelize("helloworld2")                                                                   
"Helloworld2"
iex(143)> Regex.named_captures(~r/index_table:atom_tab\n*\n.*\n.*\nentries:(?<atoms>.*)/m, :erlang.system_info(:info))
%{"atoms" => " 20963"}
iex(144)> String.to_atom(camelized)                                                                                   
:Helloworld2
iex(145)> Regex.named_captures(~r/index_table:atom_tab\n*\n.*\n.*\nentries:(?<atoms>.*)/m, :erlang.system_info(:info))
%{"atoms" => " 20964"}
iex(146)> 

I already checked issue #5 -- however I might have missed something?
Thank you!

Unless I'm missing something, it looks like this calls String.to_atom/1 on maps that could come from url params, which, given that atoms are never garbage collected exposes a denial of service vulnerability. Maybe I'm missing some validation somewhere, but it seems like this would need to verify that each key string is actually a key and never turn user input into atoms.

See: https://github.com/appcues/exconstructor/blob/master/lib/exconstructor.ex#L155-L156

Would be nice to have something akin to the

%{"nestedField" => %{id: 1}}
|>  Poison.decode! as: %Model{nested_field: [%Nested{}]}

See https://github.com/devinus/poison/pull/58/files

Hi! Very nice library but i've got problem. How can i use exconstructor if data structure is map, key type is string and key format is like GlobalIPv6Address?
For example, here what i get from docker remote api

%{"Command" => "string",
  "Created" => 1459328030, "HostConfig" => %{"NetworkMode" => "default"},
  "Id" => "string",
  "Image" => "string",
  "ImageID" => "sha256:string",
  "Labels" => %{"build-date" => "2015-12-23", "license" => "GPLv2",
    "name" => "CentOS Base Image", "vendor" => "CentOS", "string" => ""},
  "Names" => ["/boring_varahamihira"],
  "NetworkSettings" => %{"Networks" => %{"bridge" => %{"Aliases" => nil,
        "EndpointID" => "string",
        "Gateway" => "172.17.0.1", "GlobalIPv6Address" => "",
        "GlobalIPv6PrefixLen" => 0, "IPAMConfig" => nil,
        "IPAddress" => "172.17.0.2", "IPPrefixLen" => 16, "IPv6Gateway" => "",
        "Links" => nil, "MacAddress" => "02:42:ac:11:00:02",
        "NetworkID" => ""}}},
  "Ports" => [%{"IP" => "0.0.0.0", "PrivatePort" => 80, "PublicPort" => 80,
     "Type" => "tcp"}], "Status" => "Up 3 weeks"}

Wasn't trivial, at least to me, to set this working. Can I submit a PR to add to docs?

defmodule CreateShift, do: [defstruct([:shift_id]), use(ExConstructor)]

I'm not sure if I'm missing anything but I can't see the point of this library.

Native: struct = struct(TestStruct, map)
Exconstructor: struct = TestStruct.new(map)

Description

Problem parsing acronyms which are entirely uppercase within a string. Acronyms seem to be quite common is apis returning json.

What I mean by acronyms:
ImageID --> image_url, IPAddress --> ip_address

Example

  defmodule Identity.Endpoint do
    defstruct [:admin_url, :region, :internal_url, :id, :public_url]
    use ExConstructor
  end

Identity.Endpoint.new(
  %{
  "adminURL" => "adminURL", 
  "id" => "id", 
  "internalURL" => "internalURL", 
  "publicURL" => "publicURL",
   "region" => "region"
  }
)

Returns

%Identity.Endpoint{
  admin_url: nil, 
  id: "id", 
  internal_url: nil, 
  public_url: nil,
  region: "region"
}

Potential Solution:

Screen for acronyms. Pull request on its way. 🔨

It will be nice if you can pass a few structs and get something like:
from
%{"Command" => "string", "Created" => 1459328030, "HostConfig" => %{"NetworkMode" => "default"}}
to
%Container{command: "string", created: 1459328030, %HostConfig{network_mode: "default"}}

if it possible. Maybe from nested module:

defmodule Constructor do

  defmodule Container do
    defstruct command: 1, created: 2, host_config: 3

    use ExConstructor
  end

  defmodule HostConfig do
    defstruct network_mode: 1 #(or 4)

    use ExConstructor
  end
end

Hi,

what is the reason you decided not to do a check if the atom already exists?

https://github.com/appcues/exconstructor/blob/master/lib/exconstructor.ex#L155