Check Cross Origin Request Security headers.

Examples

iex> CORS.check(:GET, [], test_config())
{:ok, :no_cors}

iex> CORS.check(:OPTIONS, [], test_config())
{:ok, :no_cors}

# Need an any config
# Test config accepts PUT but not delete

Simple CORS requests

iex> headers = [{"origin", "other.example.com"}]
...> CORS.check(:GET, headers, test_config())
{:ok, {:simple, [{"access-control-allow-origin", "other.example.com"}]}}

iex> headers = [{"origin", "other.example.com"}]
...> CORS.check(:DELETE, headers, test_config())
{:error, {:simple, :invalid_method}}

Preflight CORS requests

{:ok, {:preflight, [{"access-control-allow-origin", "other.example.com"}, {"access-control-allow-methods", "PUT"}]}}
iex> headers = [
...>   {"origin", "other.example.com"},
...>   {"access-control-request-method", "PUT"},
...> ]
...> CORS.check(:OPTIONS, headers, test_config())
{:ok, {:preflight, [{"access-control-allow-origin", "other.example.com"}, {"access-control-allow-methods", "PUT"}]}}

iex> headers = [
...>   {"origin", "bad.example.com"},
...>   {"access-control-request-method", "PUT"},
...> ]
...> CORS.check(:OPTIONS, headers, test_config())
{:error, {:preflight, :invalid_origin}}