Static File

Use web::static_file to serve static files. Range / If-None-Match / If-Modified-Since headers from the request will be handled automatically, and Content-Type / Content-Disposition headers for the response will be obtained from the provided file extension.

Static Files Example

Note

The example code uses wildcard matching without checking the actual value of the path, which may cause serious security implications such as path traversal attack (../). Users should perform the validation on the input path carefully.

Note

In order to use asynchronous file i/o on linux platform, liburing must be installed and define BOOST_ASIO_HAS_IO_URING to enable it. Note that asynchonous file i/o is not supported on MacOS.

auto serve_file(path_of<std::tuple<std::string>> path, const request& req)
    -> awaitable<expected<static_file, response>>
{
  auto [file_path] = path;

  co_return static_file::open(co_await net::this_coro::executor, file_path, req)
      .transform_error([&file_path](auto) -> response {
        return response::not_found()
            .set_header(http::field::content_type, mime::text_plain())
            .set_body(
                fmt::format("requsted file was not found: \"{}\"", file_path));
      });
}

int main()
{
  auto ioc = net::io_context();
  auto server = http_server::builder(ioc)
                    .serve(route::get<"/#file_path">(serve_file))
                    .build();
  server.bind("127.0.0.1", 8080);

  ioc.run();
}