GH-3211: Add DefSftpSF.setKnownHosts(Resource) (#3212)

* GH-3211: Add DefSftpSF.setKnownHosts(Resource)

Fixes #3211

* Add `DefaultSftpSessionFactory.setKnownHosts(Resource)` to
allow to configure externally any resource for file with known_hosts content
* Deprecate an existing method in favor of new one
* The new method makes it aligned with the `setPrivateKey(Resource)`
* Fix tests do not use a deprecated method any more

**Cherry-pick to 5.2.x**

* * Rename to `setKnownHostsResource()` to avoid XML parser confusion
* Change `sftp.adoc` to reflect a new property

spring-integration-sftp/src/main/java/org/springframework/integration/sftp/session/DefaultSftpSessionFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -17,6 +17,7 @@
 package org.springframework.integration.sftp.session;
 
 import java.io.IOException;
+import java.io.InputStream;
 import java.time.Duration;
 import java.util.Arrays;
 import java.util.Properties;
@@ -27,6 +28,7 @@
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.beans.factory.BeanCreationException;
+import org.springframework.core.io.FileSystemResource;
 import org.springframework.core.io.Resource;
 import org.springframework.integration.file.remote.session.SessionFactory;
 import org.springframework.integration.file.remote.session.SharedSessionCapable;
@@ -81,7 +83,7 @@ public class DefaultSftpSessionFactory implements SessionFactory<LsEntry>, Share
 
 	private String password;
 
-	private String knownHosts;
+	private Resource knownHosts;
 
 	private Resource privateKey;
 
@@ -191,8 +193,21 @@ public void setPassword(String password) {
 	 * false (default).</b>
 	 * @param knownHosts The known hosts.
 	 * @see JSch#setKnownHosts(String)
+	 * @deprecated since 5.2.5 in favor of {@link #setKnownHostsResource(Resource)}
 	 */
+	@Deprecated
 	public void setKnownHosts(String knownHosts) {
+		setKnownHostsResource(new FileSystemResource(knownHosts));
+	}
+
+	/**
+	 * Specifies the filename that will be used for a host key repository.
+	 * The file has the same format as OpenSSH's known_hosts file.
+	 * @param knownHosts the resource for known hosts.
+	 * @see JSch#setKnownHosts(InputStream)
+	 * @since 5.2.5
+	 */
+	public void setKnownHostsResource(Resource knownHosts) {
 		this.knownHosts = knownHosts;
 	}
 
@@ -323,7 +338,7 @@ public void setEnableDaemonThread(Boolean enableDaemonThread) {
 	 * implementation must respond to Jsch calls in a suitable way.
 	 * <p>
 	 * Jsch calls {@link UserInfo#promptYesNo(String)} when connecting to an unknown host,
-	 * or when a known host's key has changed (see {@link #setKnownHosts(String)
+	 * or when a known host's key has changed (see {@link #setKnownHostsResource(Resource)}
 	 * knownHosts}). Generally, it should return false as returning true will accept all
 	 * new keys or key changes.
 	 * <p>
@@ -347,7 +362,7 @@ public void setUserInfo(UserInfo userInfo) {
 	/**
 	 * When no {@link UserInfo} has been provided, set to true to unconditionally allow
 	 * connecting to an unknown host or when a host's key has changed (see
-	 * {@link #setKnownHosts(String) knownHosts}). Default false (since 4.2).
+	 * {@link #setKnownHostsResource(Resource) knownHosts}). Default false (since 4.2).
 	 * Set to true if a knownHosts file is not provided.
 	 * @param allowUnknownKeys true to allow connecting to unknown hosts.
 	 * @since 4.1.7
@@ -380,8 +395,7 @@ public SftpSession getSession() {
 				freshJschSession = true;
 			}
 			sftpSession = new SftpSession(jschSession);
-			JavaUtils.INSTANCE
-				.acceptIfNotNull(this.channelConnectTimeout, sftpSession::setChannelConnectTimeout);
+			JavaUtils.INSTANCE.acceptIfNotNull(this.channelConnectTimeout, sftpSession::setChannelConnectTimeout);
 			sftpSession.connect();
 			if (this.isSharedSession && freshJschSession) {
 				this.sharedJschSession = jschSession;
@@ -408,8 +422,8 @@ private com.jcraft.jsch.Session initJschSession() throws JSchException, IOExcept
 		if (this.port <= 0) {
 			this.port = 22;
 		}
-		if (StringUtils.hasText(this.knownHosts)) {
-			this.jsch.setKnownHosts(this.knownHosts);
+		if (this.knownHosts != null) {
+			this.jsch.setKnownHosts(this.knownHosts.getInputStream());
 		}
 
 		// private key
@@ -467,6 +481,7 @@ public void resetSharedSession() {
 	 * sensible defaults if null. As the password is configured in this Factory, the
 	 * wrapper will return the factory's configured password and only delegate to the
 	 * UserInfo if null.
+	 *
 	 * @since 4.1.7
 	 */
 	private class UserInfoWrapper implements UserInfo, UIKeyboardInteractive {
@@ -548,7 +563,7 @@ public boolean promptYesNo(String message) {
 			}
 			else {
 				if (LOGGER.isDebugEnabled()) {
-					LOGGER.debug("No UserInfo provided - " + message + ", returning:"
+					LOGGER.debug("No UserInfo provided - " + message + ", returning: "
 							+ DefaultSftpSessionFactory.this.allowUnknownKeys);
 				}
 				return DefaultSftpSessionFactory.this.allowUnknownKeys;

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/InboundChannelAdapterParserCachingTests-context.xml

@@ -16,7 +16,7 @@
 
 	<beans:bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<beans:property name="host" value="loclahost"/>
-		<beans:property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<beans:property name="knownHostsResource" value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<beans:property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftp_rsa"/>
 		<beans:property name="privateKeyPassphrase" value="ghj"/>
 		<beans:property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/InboundChannelAdapterParserTests-context-fail-autocreate.xml

@@ -3,25 +3,17 @@
 		xmlns="http://www.springframework.org/schema/integration"
 		xmlns:beans="http://www.springframework.org/schema/beans"
 		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-		xmlns:p="http://www.springframework.org/schema/p"
-		xmlns:context="http://www.springframework.org/schema/context"
-		xmlns:util="http://www.springframework.org/schema/util"
-		xmlns:tool="http://www.springframework.org/schema/tool"
-		xmlns:lang="http://www.springframework.org/schema/lang"
 		xmlns:sftp="http://www.springframework.org/schema/integration/sftp"
 		xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
 						http://www.springframework.org/schema/integration https://www.springframework.org/schema/integration/spring-integration.xsd
-					 	http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd
-                        http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd
-						http://www.springframework.org/schema/tool https://www.springframework.org/schema/tool/spring-tool.xsd
-						http://www.springframework.org/schema/lang https://www.springframework.org/schema/lang/spring-lang.xsd
 						http://www.springframework.org/schema/integration/sftp https://www.springframework.org/schema/integration/sftp/spring-integration-sftp.xsd">
 
 	<channel id="requestChannel"/>
 
 	<beans:bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<beans:property name="host" value="loclahost"/>
-		<beans:property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<beans:property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<beans:property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<beans:property name="privateKeyPassphrase" value="ghj"/>
 		<beans:property name="password" value="hello"/>
@@ -30,17 +22,17 @@
 	</beans:bean>
 
 	<sftp:inbound-channel-adapter id="sftpAdapterNoAutoCreate"
-			channel="requestChannel"
-			session-factory="sftpSessionFactory"
-			filter="filter"
-			remote-directory="/foo"
-			local-directory="file:foo"
-			auto-create-local-directory="false"
-			delete-remote-files="false">
+								  channel="requestChannel"
+								  session-factory="sftpSessionFactory"
+								  filter="filter"
+								  remote-directory="/foo"
+								  local-directory="file:foo"
+								  auto-create-local-directory="false"
+								  delete-remote-files="false">
 		<poller fixed-rate="1000"/>
 	</sftp:inbound-channel-adapter>
 
-	<beans:bean id="filter" class="org.springframework.integration.sftp.filters.SftpPatternMatchingFileListFilter">
+	<beans:bean id="filter" class="org.springframework.integration.sftp.filters.SftpSimplePatternFileListFilter">
 		<beans:constructor-arg value="."/>
 	</beans:bean>
 

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/InboundChannelAdapterParserTests-context-fail.xml

@@ -21,7 +21,7 @@
 
 	<beans:bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.SimpleSftpSessionFactory">
 		<beans:property name="host" value="loclahost"/>
-		<beans:property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<beans:property name="knownHostsResource" value="local, foo.com, bar.foo"/>
 		<beans:property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<beans:property name="privateKeyPassphrase" value="ghj"/>
 		<beans:property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/InboundChannelAdapterParserTests-context.xml

@@ -22,7 +22,8 @@
 
 	<beans:bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<beans:property name="host" value="loclahost"/>
-		<beans:property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<beans:property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<beans:property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftp_rsa"/>
 		<beans:property name="privateKeyPassphrase" value="ghj"/>
 		<beans:property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/MessageHistory-context.xml

@@ -3,25 +3,17 @@
 		xmlns="http://www.springframework.org/schema/integration"
 		xmlns:beans="http://www.springframework.org/schema/beans"
 		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-		xmlns:p="http://www.springframework.org/schema/p"
-		xmlns:context="http://www.springframework.org/schema/context"
-		xmlns:util="http://www.springframework.org/schema/util"
-		xmlns:tool="http://www.springframework.org/schema/tool"
-		xmlns:lang="http://www.springframework.org/schema/lang"
 		xmlns:sftp="http://www.springframework.org/schema/integration/sftp"
 		xsi:schemaLocation="http://www.springframework.org/schema/beans https://www.springframework.org/schema/beans/spring-beans.xsd
 						http://www.springframework.org/schema/integration https://www.springframework.org/schema/integration/spring-integration.xsd
-					 	http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd
-                        http://www.springframework.org/schema/util https://www.springframework.org/schema/util/spring-util.xsd
-						http://www.springframework.org/schema/tool https://www.springframework.org/schema/tool/spring-tool.xsd
-						http://www.springframework.org/schema/lang https://www.springframework.org/schema/lang/spring-lang.xsd
 						http://www.springframework.org/schema/integration/sftp https://www.springframework.org/schema/integration/sftp/spring-integration-sftp.xsd">
 
 	<channel id="inboundFilesChannel"/>
 
 	<beans:bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<beans:property name="host" value="loclahost"/>
-		<beans:property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<beans:property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<beans:property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<beans:property name="privateKeyPassphrase" value="ghj"/>
 		<beans:property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/OutboundChannelAdapterParserCachingTests-context.xml

@@ -9,7 +9,8 @@
 
 	<bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<property name="host" value="localhost"/>
-		<property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<property name="privateKeyPassphrase" value="ghj"/>
 		<property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/OutboundChannelAdapterParserTests-context-fail-fileFileGen.xml

@@ -9,7 +9,7 @@
 
 	<bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.SimpleSftpSessionFactory">
 		<property name="host" value="localhost"/>
-		<property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<property name="knownHostsResource" value="local, foo.com, bar.foo"/>
 		<property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<property name="privateKeyPassphrase" value="ghj"/>
 		<property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/OutboundChannelAdapterParserTests-context-fail.xml

@@ -9,7 +9,8 @@
 
 	<bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<property name="host" value="localhost"/>
-		<property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<property name="privateKeyPassphrase" value="ghj"/>
 		<property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/OutboundChannelAdapterParserTests-context.xml

@@ -9,7 +9,8 @@
 
 	<bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<property name="host" value="localhost"/>
-		<property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftpTest"/>
 		<property name="privateKeyPassphrase" value="ghj"/>
 		<property name="password" value="hello"/>

spring-integration-sftp/src/test/java/org/springframework/integration/sftp/config/SftpInboundAutostartup-context.xml

@@ -9,7 +9,8 @@
 
 	<bean id="sftpSessionFactory" class="org.springframework.integration.sftp.session.DefaultSftpSessionFactory">
 		<property name="host" value="loclahost"/>
-		<property name="knownHosts" value="local, foo.com, bar.foo"/>
+		<property name="knownHostsResource"
+						value="#{ new org.springframework.core.io.ByteArrayResource('local, foo.com, bar.foo'.bytes)}"/>
 		<property name="privateKey" value="classpath:org/springframework/integration/sftp/config/sftp_rsa"/>
 		<property name="privateKeyPassphrase" value="ghj"/>
 		<property name="password" value="hello"/>

src/reference/asciidoc/sftp.adoc

@@ -111,7 +111,7 @@ Required.
 
 `hostKeyAlias`::Sets the host key alias, which is used when comparing the host key to the known hosts list.
 
-`knownHosts`::Specifies the filename that used for a host key repository.
+`knownHostsResource`::Specifies the file resource that used for a host key repository.
 The file has the same format as OpenSSH's `known_hosts` file and is required and must be pre-populated if `allowUnknownKeys` is false.
 
 `password`::The password to authenticate against the remote host.
@@ -163,7 +163,7 @@ If `false`, a pre-populated `knownHosts` file is required.
 In particular, `promptYesNo()` is invoked when an unknown (or changed) host key is received.
 See also <<sftp-unk-keys,`allowUnknownKeys`>>.
 When you provide a `UserInfo`, the `password` and private key `passphrase` are obtained from it, and you cannot set discrete
-`password` and `privateKeyPassprase` properties.
+`password` and `privateKeyPassphrase` properties.
 
 [[sftp-proxy-factory-bean]]
 === Proxy Factory Bean