protected Socket _openDataConnection_()

in src/main/java/org/apache/commons/net/ftp/FTPHTTPClient.java [126:166]

• 34 lines of code
• 10 McCabe index (conditional complexity)

    protected Socket _openDataConnection_(final String command, final String arg) throws IOException {
        // Force local passive mode, active mode not supported by through proxy
        if (getDataConnectionMode() != PASSIVE_LOCAL_DATA_CONNECTION_MODE) {
            throw new IllegalStateException("Only passive connection mode supported");
        }

        final boolean isInet6Address = getRemoteAddress() instanceof Inet6Address;
        String passiveHost;

        final boolean attemptEPSV = isUseEPSVwithIPv4() || isInet6Address;
        if (attemptEPSV && epsv() == FTPReply.ENTERING_EPSV_MODE) {
            _parseExtendedPassiveModeReply(_replyLines.get(0));
            passiveHost = this.tunnelHost;
        } else {
            if (isInet6Address) {
                return null; // Must use EPSV for IPV6
            }
            // If EPSV failed on IPV4, revert to PASV
            if (pasv() != FTPReply.ENTERING_PASSIVE_MODE) {
                return null;
            }
            _parsePassiveModeReply(_replyLines.get(0));
            passiveHost = this.getPassiveHost();
        }

        final Socket socket = _socketFactory_.createSocket(proxyHost, proxyPort);
        final InputStream is = socket.getInputStream();
        final OutputStream os = socket.getOutputStream();
        tunnelHandshake(passiveHost, this.getPassivePort(), is, os);
        if (getRestartOffset() > 0 && !restart(getRestartOffset())) {
            socket.close();
            return null;
        }

        if (!FTPReply.isPositivePreliminary(sendCommand(command, arg))) {
            socket.close();
            return null;
        }

        return socket;
    }