defmodule DartSass do
@moduledoc """
DartSass is a installer and runner for [sass](https://sass-lang.com/dart-sass).
## Profiles
You can define multiple dart_sass profiles. By default, there is a
profile called `:default` which you can configure its args, current
directory and environment:
config :dart_sass,
version: "1.39.0",
default: [
args: ~w(css/app.scss ../priv/static/assets/app.css),
cd: Path.expand("../assets", __DIR__)
]
"""
use Application
require Logger
@doc false
def start(_, _) do
unless Application.get_env(:dart_sass, :version) do
Logger.warn("""
dart_sass version is not configured. Please set it in your config files:
config :dart_sass, :version, "#{latest_version()}"
""")
end
configured_version = configured_version()
case bin_version() do
{:ok, ^configured_version} ->
:ok
{:ok, version} ->
Logger.warn("""
Outdated dart-sass version. Expected #{configured_version}, got #{version}. \
Please run `mix sass.install` or update the version in your config files.\
""")
:error ->
:ok
end
Supervisor.start_link([], strategy: :one_for_one)
end
@doc false
# Latest known version at the time of publishing.
def latest_version do
"1.39.0"
end
@doc """
Returns the configured dart-sass version.
"""
def configured_version do
Application.get_env(:dart_sass, :version, latest_version())
end
@doc """
Returns the configuration for the given profile.
Returns nil if the profile does not exist.
"""
def config_for!(profile) when is_atom(profile) do
Application.get_env(:dart_sass, profile) ||
raise ArgumentError, """
unknown dart_sass profile. Make sure the profile is defined in your config files, such as:
config :dart_sass,
#{profile}: [
args: ~w(css/app.scss ../priv/static/assets/app.css),
cd: Path.expand("../assets", __DIR__)
]
"""
end
@doc """
Checks whether or not dart-sass is installed.
"""
def installed? do
case bin_paths() do
{sass, nil} -> File.exists?(sass)
{vm, snapshot} -> File.exists?(vm) and File.exists?(snapshot)
end
end
@doc """
Returns the path to the executable and optional snapshot.
Depending on your environment, sass may be invoked through a
portable instance of the Dart VM. In such case, this function
will return a tuple of `{Dart, Snapshot}`, otherwise it will
return `{Sass, Nil}`.
"""
def bin_paths do
case :os.type() do
{:unix, :darwin} -> {vm_path(), snapshot_path()}
{:win32, _} -> {vm_path(), snapshot_path()}
_ -> {sass_path(), nil}
end
end
@doc false
def sass_path() do
Path.join(Path.dirname(Mix.Project.build_path()), "sass")
end
@doc false
def snapshot_path do
Path.join(Path.dirname(Mix.Project.build_path()), "sass.snapshot")
end
@doc false
def vm_path do
Path.join(Path.dirname(Mix.Project.build_path()), "dart")
end
# TODO: Remove when dart-sass will exit when stdin is closed.
@doc false
def script_path() do
Path.join(:code.priv_dir(:dart_sass), "dart_sass.bash")
end
@doc """
Returns the version of the dart_sass executable.
Returns `{:ok, version_string}` on success or `:error` when the executable
is not available.
"""
def bin_version do
{path, args} = sass(["--version"])
with true <- File.exists?(path),
{result, 0} <- System.cmd(path, args) do
{:ok, String.trim(result)}
else
_ -> :error
end
end
defp sass(args) do
{path, args} =
case bin_paths() do
{sass, nil} -> {sass, args}
{vm, snapshot} -> {vm, [snapshot] ++ args}
end
# TODO: Remove when dart-sass will exit when stdin is closed.
# Link: https://github.com/sass/dart-sass/pull/1411
cond do
"--watch" in args and not match?({:win32, _}, :os.type()) ->
{script_path(), [path] ++ args}
true ->
{path, args}
end
end
@doc """
Runs the given command with `args`.
The given args will be appended to the configured args.
The task output will be streamed directly to stdio. It
returns the status of the underlying call.
"""
def run(profile, extra_args) when is_atom(profile) and is_list(extra_args) do
config = config_for!(profile)
args = config[:args] || []
opts = [
cd: config[:cd] || File.cwd!(),
env: config[:env] || %{},
into: IO.stream(:stdio, :line),
stderr_to_stdout: true
]
{path, args} = sass(args ++ extra_args)
path
|> System.cmd(args, opts)
|> elem(1)
end
@doc """
Installs, if not available, and then runs `sass`.
Returns the same as `run/2`.
"""
def install_and_run(profile, args) do
unless installed?() do
install()
end
run(profile, args)
end
@doc """
Installs dart-sass with `configured_version/0`.
"""
def install do
version = configured_version()
tmp_dir = Path.join(System.tmp_dir!(), "cs-dart-sass")
File.rm_rf!(tmp_dir)
File.mkdir_p!(tmp_dir)
name = "dart-sass-#{version}-#{target()}"
url = "https://github.com/sass/dart-sass/releases/download/#{version}/#{name}"
archive = fetch_body!(url)
case unpack_archive(Path.extname(name), archive, tmp_dir) do
:ok -> :ok
other -> raise "couldn't unpack archive: #{inspect(other)}"
end
sass_path = sass_path()
snapshot_path = snapshot_path()
vm_path = vm_path()
case :os.type() do
{:win32, _} ->
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "dart.exe"]), vm_path)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "sass.snapshot"]), snapshot_path)
{:unix, :darwin} ->
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "dart"]), vm_path)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "sass.snapshot"]), snapshot_path)
_ ->
File.cp!(Path.join([tmp_dir, "dart-sass", "sass"]), sass_path)
end
end
defp unpack_archive(".zip", zip, cwd) do
with {:ok, _} <- :zip.unzip(zip, cwd: to_charlist(cwd)), do: :ok
end
defp unpack_archive(_, tar, cwd) do
:erl_tar.extract({:binary, tar}, [:compressed, cwd: to_charlist(cwd)])
end
# Available targets: https://github.com/sass/dart-sass/releases
defp target do
case :os.type() do
{:win32, _} ->
case :erlang.system_info(:wordsize) * 8 do
32 -> "windows-ia32.zip"
64 -> "windows-x64.zip"
end
{:unix, osname} ->
arch_str = :erlang.system_info(:system_architecture)
[arch | _] = arch_str |> List.to_string() |> String.split("-")
osname = if osname == :darwin, do: :macos, else: osname
case arch do
"amd64" -> "#{osname}-x64.tar.gz"
"x86_64" -> "#{osname}-x64.tar.gz"
_ -> raise "could not download dart_sass for architecture: #{arch_str}"
end
end
end
defp fetch_body!(url) do
url = String.to_charlist(url)
Logger.debug("Downloading dart-sass from #{url}")
{:ok, _} = Application.ensure_all_started(:inets)
{:ok, _} = Application.ensure_all_started(:ssl)
# https://erlef.github.io/security-wg/secure_coding_and_deployment_hardening/inets
cacertfile = CAStore.file_path() |> String.to_charlist()
http_options = [
autoredirect: false,
ssl: [
verify: :verify_peer,
cacertfile: cacertfile,
depth: 2,
customize_hostname_check: [
match_fun: :public_key.pkix_verify_hostname_match_fun(:https)
]
]
]
case :httpc.request(:get, {url, []}, http_options, []) do
{:ok, {{_, 302, _}, headers, _}} ->
{'location', download} = List.keyfind(headers, 'location', 0)
options = [body_format: :binary]
case :httpc.request(:get, {download, []}, http_options, options) do
{:ok, {{_, 200, _}, _, body}} ->
body
other ->
raise "couldn't fetch #{download}: #{inspect(other)}"
end
other ->
raise "couldn't fetch #{url}: #{inspect(other)}"
end
end
end
