Future _writeResponse()

in lib/shelf_io.dart [182:231]
33 lines of code
11 McCabe index (conditional complexity)

Future _writeResponse(Response response, HttpResponse httpResponse) {
  if (response.context.containsKey('shelf.io.buffer_output')) {
    httpResponse.bufferOutput =
        response.context['shelf.io.buffer_output'] as bool;
  }

  httpResponse.statusCode = response.statusCode;

  // An adapter must not add or modify the `Transfer-Encoding` parameter, but
  // the Dart SDK sets it by default. Set this before we fill in
  // [response.headers] so that the user or Shelf can explicitly override it if
  // necessary.
  httpResponse.headers.chunkedTransferEncoding = false;

  response.headersAll.forEach((header, value) {
    httpResponse.headers.set(header, value);
  });

  var coding = response.headers['transfer-encoding'];
  if (coding != null && !equalsIgnoreAsciiCase(coding, 'identity')) {
    // If the response is already in a chunked encoding, de-chunk it because
    // otherwise `dart:io` will try to add another layer of chunking.
    //
    // TODO(nweiz): Do this more cleanly when sdk#27886 is fixed.
    response = response.change(
      body: chunkedCoding.decoder.bind(response.read()),
    );
    httpResponse.headers.set(HttpHeaders.transferEncodingHeader, 'chunked');
  } else if (response.statusCode >= 200 &&
      response.statusCode != 204 &&
      response.statusCode != 304 &&
      response.contentLength == null &&
      response.mimeType != 'multipart/byteranges') {
    // If the response isn't chunked yet and there's no other way to tell its
    // length, enable `dart:io`'s chunked encoding.
    httpResponse.headers.set(HttpHeaders.transferEncodingHeader, 'chunked');
  }

  if (!response.headers.containsKey(HttpHeaders.serverHeader)) {
    httpResponse.headers.set(HttpHeaders.serverHeader, 'dart:io with Shelf');
  }

  if (!response.headers.containsKey(HttpHeaders.dateHeader)) {
    httpResponse.headers.date = DateTime.now().toUtc();
  }

  return httpResponse
      .addStream(response.read())
      .then((_) => httpResponse.close());
}