SFTP Consumer/Sink

Resolves https://github.com/spring-cloud/stream-applications/issues/32

functions/common/function-test-support/src/main/java/org/springframework/cloud/fn/test/support/sftp/SftpTestSupport.java

@@ -0,0 +1,120 @@
+/*
+ * Copyright 2015-2020 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
+ *
+ *      https://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.springframework.cloud.fn.test.support.sftp;
+
+import java.io.File;
+import java.io.InputStream;
+import java.math.BigInteger;
+import java.nio.ByteBuffer;
+import java.security.KeyFactory;
+import java.security.PublicKey;
+import java.security.spec.RSAPublicKeySpec;
+import java.util.Arrays;
+import java.util.Collections;
+
+import org.apache.sshd.common.file.virtualfs.VirtualFileSystemFactory;
+import org.apache.sshd.server.SshServer;
+import org.apache.sshd.server.keyprovider.SimpleGeneratorHostKeyProvider;
+import org.apache.sshd.server.subsystem.sftp.SftpSubsystemFactory;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+
+import org.springframework.cloud.fn.test.support.file.remote.RemoteFileTestSupport;
+import org.springframework.core.io.ClassPathResource;
+import org.springframework.util.Base64Utils;
+import org.springframework.util.FileCopyUtils;
+import org.springframework.util.StringUtils;
+
+/**
+ * Provides an embedded SFTP Server for test cases.
+ *
+ * @author David Turanski
+ * @author Gary Russell
+ * @author Artem Bilan
+ */
+public class SftpTestSupport extends RemoteFileTestSupport {
+
+	private static SshServer server;
+
+	@Override
+	public String prefix() {
+		return "sftp";
+	}
+
+	@BeforeAll
+	public static void createServer() throws Exception {
+		server = SshServer.setUpDefaultServer();
+		server.setPasswordAuthenticator((username, password, session) ->
+				StringUtils.hasText(password) && !"badPassword".equals(password)); // fail if pub key validation failed
+		server.setPublickeyAuthenticator((username, key, session) -> key.equals(decodePublicKey("id_rsa_pp.pub.rename2")));
+		server.setPort(0);
+		server.setKeyPairProvider(new SimpleGeneratorHostKeyProvider(new File("hostkey.ser")));
+		server.setSubsystemFactories(Collections.singletonList(new SftpSubsystemFactory()));
+		server.setFileSystemFactory(new VirtualFileSystemFactory(remoteTemporaryFolder));
+		server.start();
+		System.setProperty("sftp.consumer.factory.port", String.valueOf(server.getPort()));
+		System.setProperty("sftp.consumer.localDir",
+				localTemporaryFolder + File.separator + "localTarget");
+	}
+
+	@AfterAll
+	public static void stopServer() throws Exception {
+		server.stop();
+		File hostkey = new File("hostkey.ser");
+		if (hostkey.exists()) {
+			hostkey.delete();
+		}
+		System.clearProperty("sftp.consumer.factory.port");
+		System.clearProperty("sftp.consumer.localDir");
+	}
+
+	private static PublicKey decodePublicKey(String key) {
+		try {
+			InputStream stream = new ClassPathResource(key).getInputStream();
+			byte[] keyBytes = FileCopyUtils.copyToByteArray(stream);
+			// strip any newline chars
+			while (keyBytes[keyBytes.length - 1] == 0x0a || keyBytes[keyBytes.length - 1] == 0x0d) {
+				keyBytes = Arrays.copyOf(keyBytes, keyBytes.length - 1);
+			}
+			byte[] decodeBuffer = Base64Utils.decode(keyBytes);
+			ByteBuffer bb = ByteBuffer.wrap(decodeBuffer);
+			int len = bb.getInt();
+			byte[] type = new byte[len];
+			bb.get(type);
+			if ("ssh-rsa".equals(new String(type))) {
+				BigInteger e = decodeBigInt(bb);
+				BigInteger m = decodeBigInt(bb);
+				RSAPublicKeySpec spec = new RSAPublicKeySpec(m, e);
+				return KeyFactory.getInstance("RSA").generatePublic(spec);
+
+			}
+			else {
+				throw new IllegalArgumentException("Only supports RSA");
+			}
+		}
+		catch (Exception e) {
+			throw new IllegalStateException("Failed to determine the test public key", e);
+		}
+	}
+
+	private static BigInteger decodeBigInt(ByteBuffer bb) {
+		int len = bb.getInt();
+		byte[] bytes = new byte[len];
+		bb.get(bytes);
+		return new BigInteger(bytes);
+	}
+}