feat: adds support for wildcard host validation

components/abstractions/src/main/java/com/microsoft/kiota/authentication/AllowedHostsValidator.java

@@ -58,7 +58,18 @@ public void setAllowedHosts(@Nonnull final Set<String> allowedHosts) {
      * @return true if the host is allowed, false otherwise.
      */
     public boolean isUrlHostValid(@Nonnull final URI uri) {
-        return validHosts.isEmpty()
-                || validHosts.contains(uri.getHost().trim().toLowerCase(Locale.ROOT));
+        if (validHosts.isEmpty()) {
+            return true;
+        }
+        final String host = uri.getHost().trim().toLowerCase(Locale.ROOT);
+        if (validHosts.contains(host)) {
+            return true;
+        }
+        for (final String validHost : validHosts) {
+            if (validHost.startsWith(".") && host.endsWith(validHost)) {
+                return true;
+            }
+        }
+        return false;
     }
 }

components/abstractions/src/test/java/com/microsoft/kiota/authentication/AllowedHostValidatorTest.java

@@ -1,13 +1,15 @@
 package com.microsoft.kiota.authentication;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertFalse;
 import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import org.junit.jupiter.api.Test;
 
 import java.net.URI;
 import java.net.URISyntaxException;
+import java.util.Collections;
 
 class AllowedHostValidatorTest {
 
@@ -34,4 +36,61 @@ void initialisesAllowedHostsSuccessfully() throws URISyntaxException {
         assertTrue(validator.getAllowedHosts().contains("graph.microsoft.us"));
         assertTrue(validator.isUrlHostValid(new URI("https://graph.microsoft.com/v1/me")));
     }
+
+    @Test
+    void returnsFalseForSubdomainMatchingExactHost() throws URISyntaxException {
+        final AllowedHostsValidator validator = new AllowedHostsValidator("example.com");
+
+        assertFalse(validator.isUrlHostValid(new URI("https://sub.example.com/path")));
+    }
+
+    @Test
+    void returnsTrueForSubdomainMatchingAllowedSuffix() throws URISyntaxException {
+        final AllowedHostsValidator validator = new AllowedHostsValidator(".fabric.microsoft.com");
+
+        assertTrue(
+                validator.isUrlHostValid(
+                        new URI("https://abc.123.graphql.fabric.microsoft.com/path")));
+    }
+
+    @Test
+    void returnsFalseForBareDomainWhenAllowedAsSuffix() throws URISyntaxException {
+        final AllowedHostsValidator validator = new AllowedHostsValidator(".fabric.microsoft.com");
+
+        assertFalse(validator.isUrlHostValid(new URI("https://fabric.microsoft.com/path")));
+    }
+
+    @Test
+    void suffixHostMatchingIsCaseInsensitive() throws URISyntaxException {
+        final AllowedHostsValidator validator = new AllowedHostsValidator(".Fabric.Microsoft.COM");
+
+        assertTrue(
+                validator.isUrlHostValid(
+                        new URI("https://ABC.z2c.graphql.fabric.microsoft.com/path")));
+    }
+
+    @Test
+    void allowsMultipleValidHosts() throws URISyntaxException {
+        final AllowedHostsValidator validator =
+                new AllowedHostsValidator(
+                        "example.com", "api.example.com", ".fabric.microsoft.com");
+
+        assertTrue(validator.isUrlHostValid(new URI("https://example.com/path")));
+        assertTrue(validator.isUrlHostValid(new URI("https://api.example.com/path")));
+        assertFalse(validator.isUrlHostValid(new URI("https://other.com/path")));
+        assertTrue(
+                validator.isUrlHostValid(
+                        new URI("https://abc.123.graphql.fabric.microsoft.com/path")));
+    }
+
+    @Test
+    void allowsSuffixBasedHostsAfterUpdate() throws URISyntaxException {
+        final AllowedHostsValidator validator = new AllowedHostsValidator("example.com");
+
+        validator.setAllowedHosts(Collections.singleton(".fabric.microsoft.com"));
+
+        assertTrue(
+                validator.isUrlHostValid(
+                        new URI("https://abc.123.graphql.fabric.microsoft.com/path")));
+    }
 }