defmodule DartSass do
@moduledoc """
DartSass is a installer and runner for [Sass](https://sass-lang.com/dart-sass).
## Profiles
You can define multiple configuration profiles. By default, there is a
profile called `:default` which you can configure its args, current
directory and environment:
config :dart_sass,
version: "1.54.5",
default: [
args: ~w(css/app.scss ../priv/static/assets/app.css),
cd: Path.expand("../assets", __DIR__)
]
## Dart Sass configuration
There are two global configurations for the `dart_sass` application:
* `:version` - the expected Sass version.
* `:path` - the path to the Sass executable. By default
it is automatically downloaded and placed inside the `_build` directory
of your current app. Note that if your system architecture requires a
separate Dart VM executable to run, then `:path` should be defined as a
list of absolute paths.
Overriding the `:path` is not recommended, as we will automatically
download and manage `sass` for you. But in case you can't download
it (for example, the GitHub releases are behind a proxy), you may want to
set the `:path` to a configurable system location.
For instance, you can install `sass` globally with `npm`:
$ npm install -g sass
Then the executable will be at:
NPM_ROOT/sass/sass.js
Where `NPM_ROOT` is the result of `npm root -g`.
Once you find the location of the executable, you can store it in a
`MIX_SASS_PATH` environment variable, which you can then read in
your configuration file:
config :dart_sass, path: System.get_env("MIX_SASS_PATH")
"""
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Outdated dart-sass version.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
"1.54.5"
end
@doc """
Returns the configured 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 named #{inspect(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 """
Returns the path to the `sass` executable.
Depending on your system target architecture, the path may be
preceeded by the path to the Dart VM executable.
"""
def bin_path do
cond do
env_path = Application.get_env(:dart_sass, :path) ->
List.wrap(env_path)
Code.ensure_loaded?(Mix.Project) ->
platform = platform()
bin_path(platform, Path.dirname(Mix.Project.build_path()))
true ->
platform = platform()
bin_path(platform, "_build")
end
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 Sass executable (or snapshot).
Returns `{:ok, version_string}` on success or `:error` when the executable
is not available.
"""
def bin_version do
path = bin_path()
with true <- path_exists?(path),
{result, 0} <- cmd(path, ["--version"]) do
{:ok, String.trim(result)}
else
_ -> :error
end
end
defp cmd(path, args) do
cmd(path, args, [])
end
defp cmd([command | args], extra_args, opts) do
System.cmd(command, args ++ extra_args, opts)
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)
config_args = config[:args] || []
opts = [
cd: config[:cd] || File.cwd!(),
env: config[:env] || %{},
into: IO.stream(:stdio, :line),
stderr_to_stdout: true
]
args = config_args ++ extra_args
path = bin_path()
# TODO: Remove when dart-sass will exit when stdin is closed.
# Link: https://github.com/sass/dart-sass/pull/1411
path =
if "--watch" in args and platform() != :windows do
[script_path() | path]
else
path
end
path
|> 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 path_exists?(bin_path()) do
install()
end
run(profile, args)
end
@doc """
Installs dart-sass with `configured_version/0`.
"""
def install do
version = configured_version()
tmp_opts = if System.get_env("MIX_XDG"), do: %{os: :linux}, else: %{}
tmp_dir =
freshdir_p(:filename.basedir(:user_cache, "cs-sass", tmp_opts)) ||
freshdir_p(Path.join(System.tmp_dir!(), "cs-sass")) ||
raise "could not install sass. Set MIX_XDG=1 and then set XDG_CACHE_HOME to the path you want to use as cache"
platform = platform()
name = "dart-sass-#{version}-#{target_extname(platform)}"
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
path = bin_path()
case platform do
:linux ->
[sass | _] = path
File.rm(sass)
File.cp!(Path.join([tmp_dir, "dart-sass", "sass"]), sass)
:macos ->
[dart, snapshot | _] = path
File.rm(dart)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "dart"]), dart)
File.rm(snapshot)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "sass.snapshot"]), snapshot)
:windows ->
[dart, snapshot | _] = path
File.rm(dart)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "dart.exe"]), dart)
File.rm(snapshot)
File.cp!(Path.join([tmp_dir, "dart-sass", "src", "sass.snapshot"]), snapshot)
end
end
defp bin_path(platform, base_path) do
target = target(platform)
case platform do
:linux ->
[Path.join(base_path, "sass-#{target}")]
_ ->
[
Path.join(base_path, "dart-#{target}"),
Path.join(base_path, "sass.snapshot-#{target}")
]
end
end
defp platform do
case :os.type() do
{:unix, :darwin} -> :macos
{:unix, :linux} -> :linux
{:unix, osname} -> raise "dart_sass is not available for osname: #{inspect(osname)}"
{:win32, _} -> :windows
end
end
defp path_exists?(path) do
Enum.all?(path, &File.exists?/1)
end
defp freshdir_p(path) do
with {:ok, _} <- File.rm_rf(path),
:ok <- File.mkdir_p(path) do
path
else
_ -> nil
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
defp target_extname(platform) do
target = target(platform)
case platform do
:windows -> "#{target}.zip"
_ -> "#{target}.tar.gz"
end
end
# Available targets: https://github.com/sass/dart-sass/releases
defp target(:windows) do
case :erlang.system_info(:wordsize) * 8 do
32 -> "windows-ia32"
64 -> "windows-x64"
end
end
defp target(platform) do
arch_str = :erlang.system_info(:system_architecture)
[arch | _] = arch_str |> List.to_string() |> String.split("-")
# TODO: remove "arm" when we require OTP 24
case arch do
"amd64" -> "#{platform}-x64"
"aarch64" -> "#{platform}-arm64"
"arm" -> "#{platform}-arm64"
"x86_64" -> "#{platform}-x64"
"i686" -> "#{platform}-ia32"
"i386" -> "#{platform}-ia32"
_ -> raise "dart_sass not available for architecture: #{arch_str}"
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)
if proxy = System.get_env("HTTP_PROXY") || System.get_env("http_proxy") do
Logger.debug("Using HTTP_PROXY: #{proxy}")
%{host: host, port: port} = URI.parse(proxy)
:httpc.set_options([{:proxy, {{String.to_charlist(host), port}, []}}])
end
if proxy = System.get_env("HTTPS_PROXY") || System.get_env("https_proxy") do
Logger.debug("Using HTTPS_PROXY: #{proxy}")
%{host: host, port: port} = URI.parse(proxy)
:httpc.set_options([{:https_proxy, {{String.to_charlist(host), port}, []}}])
end
# https://erlef.github.io/security-wg/secure_coding_and_deployment_hardening/inets
cacertfile = cacertfile() |> 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)
],
versions: protocol_versions()
]
]
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
defp protocol_versions do
if otp_version() < 25 do
[:"tlsv1.2"]
else
[:"tlsv1.2", :"tlsv1.3"]
end
end
defp otp_version do
:erlang.system_info(:otp_release) |> List.to_integer()
end
defp cacertfile() do
Application.get_env(:dart_sass, :cacerts_path) || CAStore.file_path()
end
end
