[GH-516] SFTP: fix filesystem-id parsing in getFileSystem(URI)

- Allow userinfo without password
- Validate hostname is present

Also-by: Thomas Wolf <twolf@apache.org>

Author: ago1024

sshd-sftp/src/main/java/org/apache/sshd/sftp/client/fs/SftpFileSystemProvider.java

@@ -1499,10 +1499,9 @@ public static String getOctalPermissions(Collection<PosixFilePermission> perms)
      * @see        #getFileSystemIdentifier(String, int, String)
      */
     public static String getFileSystemIdentifier(URI uri) {
-        String userInfo = ValidateUtils.checkNotNullAndNotEmpty(uri.getUserInfo(), "UserInfo not provided");
-        String[] ui = GenericUtils.split(userInfo, ':');
-        ValidateUtils.checkTrue(GenericUtils.length(ui) == 2, "Invalid user info: %s", userInfo);
-        return getFileSystemIdentifier(uri.getHost(), uri.getPort(), ui[0]);
+        String host = ValidateUtils.checkNotNullAndNotEmpty(uri.getHost(), "Host not provided");
+        BasicCredentialsProvider credentials = ValidateUtils.checkNotNull(parseCredentials(uri), "UserInfo not provided");
+        return getFileSystemIdentifier(host, uri.getPort(), credentials.getUsername());
     }
 
     /**

sshd-sftp/src/test/java/org/apache/sshd/sftp/client/fs/SftpFileSystemProviderURITest.java

@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you 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 org.apache.sshd.sftp.client.fs;
+
+import java.net.URI;
+import java.util.stream.Stream;
+
+import org.apache.sshd.util.test.JUnitTestSupport;
+import org.junit.jupiter.api.MethodOrderer.MethodName;
+import org.junit.jupiter.api.Tag;
+import org.junit.jupiter.api.TestMethodOrder;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+@TestMethodOrder(MethodName.class)
+@Tag("NoIoTestCase")
+class SftpFileSystemProviderURITest extends JUnitTestSupport {
+
+    static Stream<Arguments> parameters() {
+        return Stream.of( //
+                Arguments.of(URI.create("sftp://username:password@host"), "host:22:username"),
+                Arguments.of(URI.create("sftp://username:password@host:22"), "host:22:username"),
+                Arguments.of(URI.create("sftp://username@host"), "host:22:username"),
+                Arguments.of(URI.create("sftp://username:password@host:2222"), "host:2222:username"),
+                Arguments.of(URI.create("sftp://username:password@host:22/path"), "host:22:username"));
+    }
+
+    @MethodSource("parameters")
+    @ParameterizedTest(name = "uri={0}")
+    void getFileSystemIdentifierFromUri(URI uri, String expected) {
+        assertEquals(expected, SftpFileSystemProvider.getFileSystemIdentifier(uri), "Mismatched filesystem identifier");
+    }
+
+    static Stream<Arguments> invalid() {
+        return Stream.of( //
+                Arguments.of(URI.create(""), "Host not provided"),
+                Arguments.of(URI.create("sftp://host:22"), "UserInfo not provided"),
+                Arguments.of(URI.create("sftp://@host:22"), "UserInfo not provided"));
+    }
+
+    @MethodSource("invalid")
+    @ParameterizedTest(name = "uri={0}")
+    void getFileSystemIdentifierFromInvalidUri(URI uri, String message) {
+        IllegalArgumentException exception = assertThrows(IllegalArgumentException.class,
+                () -> SftpFileSystemProvider.getFileSystemIdentifier(uri));
+        assertEquals(message, exception.getMessage());
+    }
+
+}