Future writeHeaders()

in lib/src/http_impl.dart [1177:1222]
45 lines of code
17 McCabe index (conditional complexity)

  Future writeHeaders({bool drainRequest = true, bool setOutgoing = true}) {
    if (headersWritten) return null;
    headersWritten = true;
    Future drainFuture;
    bool gzip = false;
    if (outbound is _HttpResponse) {
      // Server side.
      _HttpResponse response = outbound;
      if (response._httpRequest._httpServer.autoCompress &&
          outbound.bufferOutput &&
          outbound.headers.chunkedTransferEncoding) {
        List acceptEncodings =
            response._httpRequest.headers[HttpHeaders.ACCEPT_ENCODING];
        List contentEncoding = outbound.headers[HttpHeaders.CONTENT_ENCODING];
        if (acceptEncodings != null &&
            acceptEncodings
                .expand((list) => list.split(","))
                .any((encoding) => encoding.trim().toLowerCase() == "gzip") &&
            contentEncoding == null) {
          outbound.headers.set(HttpHeaders.CONTENT_ENCODING, "gzip");
          gzip = true;
        }
      }
      if (drainRequest && !response._httpRequest._incoming.hasSubscriber) {
        drainFuture = response._httpRequest.drain().catchError((_) {});
      }
    } else {
      drainRequest = false;
    }
    if (!ignoreBody) {
      if (setOutgoing) {
        int contentLength = outbound.headers.contentLength;
        if (outbound.headers.chunkedTransferEncoding) {
          chunked = true;
          if (gzip) this.gzip = true;
        } else if (contentLength >= 0) {
          this.contentLength = contentLength;
        }
      }
      if (drainFuture != null) {
        return drainFuture.then((_) => outbound._writeHeader());
      }
    }
    outbound._writeHeader();
    return null;
  }