apache/shenyu · error · IllegalArgumentException

The URI must be blank

Error message

The URI must be blank

What it means

The IS_BLANK operator's validator (blankPathValidator) requires the condition value to be blank/empty — that operator tests for an absent URI. If a non-blank value is supplied together with operator IS_BLANK, validation fails because the value is meaningless for that operator.

Solutions

1. Pass an empty or null value when using the IS_BLANK operator.
2. Change the operator to one that takes a value (e.g. EQ, PATH_PATTERN) if you actually meant to match a URI.
3. Clear the value field in the dashboard when switching the operator to IS_BLANK.

Example fix

// before
UriConditionValidator.validate("isBlank", "/api/foo");
// after
UriConditionValidator.validate("isBlank", null); // or ""

if ("isBlank".equals(operator) && value != null && !value.isBlank()) { throw new IllegalArgumentException("Operator isBlank requires an empty value"); }

boolean isBlankOperatorValueValid(String operator, String value) { return !"isBlank".equals(operator) || (value == null || value.isBlank()); }

try { UriConditionValidator.validate(operator, value); } catch (IllegalArgumentException e) { log.warn("Operator/value mismatch: {} {}", operator, value); }

When it happens

Trigger: Calling UriConditionValidator.validate("isBlank", someValue) (or the OperatorEnum.IS_BLANK alias) with a value that is not null/empty — e.g. validate("isBlank", "/api").

Common situations: Selecting IS_BLANK in the dashboard but forgetting to clear the value field, or reusing condition-building code that always sets a value regardless of operator.

Understand the failure class

Background: "Must be a positive integer", "Invalid value", "Unsupported": the invalid-argument-value error family, when a library rejects the value you pass — this error's family across 35 libraries.

Related errors

• The URI must start with '/'
• The URI cannot contain whitespaces. Current value: " + value
• The URI condition value cannot be empty.
• namespaceId is null
• namespaceId is not exist

AI-assisted analysis of apache/shenyu@567142e072 (2026-09-12). Data as JSON: /api/errors/01c99813b3258ceb. Report an issue: GitHub.

Appendix: source

Thrown at shenyu-admin/src/main/java/org/apache/shenyu/admin/validation/validator/UriConditionValidator.java:46

import java.util.function.Consumer;

public class UriConditionValidator {

    private static final Map<String, Consumer<String>> VALIDATOR_MAP = new HashMap<>();

    static {
        Consumer<String> commonPathValidator = value -> {
            if (!value.startsWith("/")) {
                throw new IllegalArgumentException("The URI must start with '/'");
            }
            if (StringUtils.containsAny(value, " ", "\t", "\n")) {
                throw new IllegalArgumentException(
                        "The URI cannot contain whitespaces. Current value: " + value);
            }
        };
        Consumer<String> blankPathValidator = value -> {
            if (StringUtils.isNotBlank(value)) {
                throw new IllegalArgumentException("The URI must be blank");
            }
        };
        VALIDATOR_MAP.put(OperatorEnum.PATH_PATTERN.getAlias(),
                PathPatternParser.defaultInstance::parse);
        VALIDATOR_MAP.put(OperatorEnum.REGEX.getAlias(), Pattern::compile);
        VALIDATOR_MAP.put(OperatorEnum.EQ.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.STARTS_WITH.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.ENDS_WITH.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.MATCH.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.EXCLUDE.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.CONTAINS.getAlias(), commonPathValidator);
        VALIDATOR_MAP.put(OperatorEnum.IS_BLANK.getAlias(), blankPathValidator);
    }

    public static void validate(final String operator, final String value) {
        if (!OperatorEnum.IS_BLANK.getAlias().equals(operator) && StringUtils.isBlank(value)) {
            throw new IllegalArgumentException("The URI condition value cannot be empty.");
        }

View on GitHub (pinned to 567142e072)