public Boolean validateUpgradeReply()

in src/main/java/com/microsoft/azure/proton/transport/ws/impl/WebSocketUpgrade.java [118:181]
46 lines of code
18 McCabe index (conditional complexity)

    public Boolean validateUpgradeReply(byte[] responseBytes) {
        final String httpString = new String(responseBytes, StandardCharsets.UTF_8);

        boolean isStatusLineOk = false;
        boolean isUpgradeHeaderOk = false;
        boolean isConnectionHeaderOk = false;
        boolean isProtocolHeaderOk = false;
        boolean isAcceptHeaderOk = false;

        final Scanner scanner = new Scanner(httpString);

        while (scanner.hasNextLine()) {
            final String line = scanner.nextLine();
            final String lowercase = line.toLowerCase(Locale.ROOT);

            if ((lowercase.contains("http/1.1"))
                    && (line.contains("101"))
                    && (lowercase.contains("switching protocols"))) {
                isStatusLineOk = true;

                continue;
            }

            if ((lowercase.contains("upgrade")) && (lowercase.contains("websocket"))) {
                isUpgradeHeaderOk = true;

                continue;
            }

            if ((lowercase.contains("connection")) && (lowercase.contains("upgrade"))) {
                isConnectionHeaderOk = true;

                continue;
            }

            if (lowercase.contains("sec-websocket-protocol") && (lowercase.contains(protocol.toLowerCase(Locale.ROOT)))) {
                isProtocolHeaderOk = true;

                continue;
            }

            if (lowercase.contains("sec-websocket-accept")) {
                MessageDigest messageDigest = null;

                try {
                    messageDigest = MessageDigest.getInstance("SHA-1");
                } catch (NoSuchAlgorithmException e) {
                    // can't happen since SHA-1 is a known digest
                    break;
                }

                final byte[] bytes = (this.webSocketKey + RFC_GUID).getBytes(StandardCharsets.ISO_8859_1);
                final String expectedKey = Base64.encodeBase64StringLocal(messageDigest.digest(bytes)).trim();

                if (line.contains(expectedKey)) {
                    isAcceptHeaderOk = true;
                }
            }
        }

        scanner.close();

        return (isStatusLineOk) && (isUpgradeHeaderOk) && (isConnectionHeaderOk) && (isProtocolHeaderOk) && (isAcceptHeaderOk);
    }