1 files changed, 89 insertions, 0 deletions
diff --git a/src/main/java/com/networknt/schema/JsonSchemaIdValidator.java b/src/main/java/com/networknt/schema/JsonSchemaIdValidator.java
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+++ b/src/main/java/com/networknt/schema/JsonSchemaIdValidator.java
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+/*
+ * Copyright (c) 2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.networknt.schema;
+
+import java.net.URI;
+import java.net.URISyntaxException;
+
+/**
+ * Validator for validating the correctness of $id.
+ */
+public interface JsonSchemaIdValidator {
+    /**
+     * Validates if the $id value is valid.
+     * 
+     * @param id                     the $id or id
+     * @param rootSchema             true if this is a root schema
+     * @param schemaLocation         the schema location
+     * @param resolvedSchemaLocation the schema location after resolving with the id
+     * @param validationContext      the validation context for instance to get the
+     *                               meta schema
+     * @return true if valid
+     */
+    boolean validate(String id, boolean rootSchema, SchemaLocation schemaLocation,
+            SchemaLocation resolvedSchemaLocation, ValidationContext validationContext);
+
+    public static final JsonSchemaIdValidator DEFAULT = new DefaultJsonSchemaIdValidator();
+
+    /**
+     * Implementation of {@link JsonSchemaIdValidator}.
+     * <p>
+     * Note that this does not strictly follow the specification.
+     * <p>
+     * This allows an $id that isn't an absolute-IRI on the root schema but it must
+     * resolve to an absolute-IRI given a base-IRI.
+     * <p>
+     * This also allows non-empty fragments.
+     */
+    public static class DefaultJsonSchemaIdValidator implements JsonSchemaIdValidator {
+        @Override
+        public boolean validate(String id, boolean rootSchema, SchemaLocation schemaLocation,
+                SchemaLocation resolvedSchemaLocation, ValidationContext validationContext) {
+            if (hasNoContext(schemaLocation)) {
+                // The following are non-standard
+                if (isFragment(id) || startsWithSlash(id)) {
+                    return true;
+                }
+            }
+            return resolvedSchemaLocation.getAbsoluteIri() != null
+                    && isAbsoluteIri(resolvedSchemaLocation.getAbsoluteIri().toString());
+        }
+
+        protected boolean startsWithSlash(String id) {
+            return id.startsWith("/");
+        }
+
+        protected boolean isFragment(String id) {
+            return id.startsWith("#");
+        }
+        
+        protected boolean hasNoContext(SchemaLocation schemaLocation) {
+            return schemaLocation.getAbsoluteIri() == null || schemaLocation.toString().startsWith("#");
+        }
+
+        protected boolean isAbsoluteIri(String iri) {
+            if (!iri.contains(":")) {
+                return false; // quick check
+            }
+            try {
+                new URI(iri);
+            } catch (URISyntaxException e) {
+                return false;
+            }
+            return true;
+        }
+    }
+}