我正在使用SFTP連接器作爲出站端點。在Mule中使用動態值，其中MEL不受支持
我需要能夠動態設置身份驗證標識文件和密碼。這是因爲我們正在動態選擇我們發送文件的位置。
看來在我使用的Mule版本中（5.2）不支持在這個特定領域中使用MEL。它適用於其他領域，但不適用於身份驗證。
是否有一個簡單的方法可以讓我動態地填充該字段？
我已經考慮擴展SFTP組件，並通過MEL處理getIdentityFile（）方法，但這是我想避免的極端解決方案，如果可以的話。
謝謝！
讓這個工作有點任務，但它確實可行。
一般的步驟是使用<service-overrides>標記覆蓋特定的組件，最終允許執行Java代碼來評估標識文件爲MEL表達式。
我們覆蓋包含在騾子SFTP組件Github上庫，這裏的類：https://github.com/muleforge/SFTP/tree/master/src/main/java/org/mule/transport/sftp
首先，您需要使用相應的服務，超越您的SFTP連接器：
<sftp:connector name="SEND_SFTP">
<service-overrides dispatcherFactory="customsftp.CustomSftpDispatcherFactory" />
</sftp:connector>
然後創建允許您實現上述邏輯的Java類：
public class CustomSftpDispatcherFactory extends SftpMessageDispatcherFactory {
@Override
public MessageDispatcher create(OutboundEndpoint endpoint) throws MuleException
{
return new CustomSftpMessageDispatcher(endpoint);
}
}
接下來更新SftpMessageDispatcher班。這個類：
public class CustomSftpMessageDispatcher extends AbstractMessageDispatcher
{
private SftpConnector connector;
private SftpUtil sftpUtil;
public CustomSftpMessageDispatcher(OutboundEndpoint endpoint)
{
super(endpoint);
connector = (SftpConnector) endpoint.getConnector();
sftpUtil = new CustomSftpUtil(endpoint);
}
protected void doDisconnect() throws Exception
{
// no op
}
protected void doDispose()
{
// no op
}
protected void doDispatch(MuleEvent event) throws Exception
{
String filename = buildFilename(event);
InputStream inputStream = generateInputStream(event);
if (logger.isDebugEnabled())
{
logger.debug("Writing file to: " + endpoint.getEndpointURI() + " [" + filename + "]");
}
SftpClient client = null;
boolean useTempDir = false;
String transferFilename = null;
try
{
String serviceName = (event.getFlowConstruct() == null)
? "UNKNOWN SERVICE"
: event.getFlowConstruct().getName();
SftpNotifier notifier = new SftpNotifier(connector, event.getMessage(), endpoint, serviceName);
client = connector.createSftpClient(endpoint, notifier);
String destDir = endpoint.getEndpointURI().getPath();
if (logger.isDebugEnabled())
{
logger.debug("Connection setup successful, writing file.");
}
// Duplicate Handling
filename = client.duplicateHandling(destDir, filename, sftpUtil.getDuplicateHandling());
transferFilename = filename;
useTempDir = sftpUtil.isUseTempDirOutbound();
if (useTempDir)
{
// TODO move to a init-method like doConnect?
// cd to tempDir and create it if it doesn't already exist
sftpUtil.cwdToTempDirOnOutbound(client, destDir);
// Add unique file-name (if configured) for use during transfer to
// temp-dir
boolean addUniqueSuffix = sftpUtil.isUseTempFileTimestampSuffix();
if (addUniqueSuffix)
{
transferFilename = sftpUtil.createUniqueSuffix(transferFilename);
}
}
// send file over sftp
// choose appropriate writing mode
if (sftpUtil.getDuplicateHandling().equals(SftpConnector.PROPERTY_DUPLICATE_HANDLING_APPEND))
{
client.storeFile(transferFilename, inputStream, SftpClient.WriteMode.APPEND);
}
else
{
client.storeFile(transferFilename, inputStream);
}
if (useTempDir)
{
// Move the file to its final destination
client.rename(transferFilename, destDir + "/" + filename);
}
logger.info("Successfully wrote file '" + filename + "' to " + endpoint.getEndpointURI());
}
catch (Exception e)
{
logger.error("Unexpected exception attempting to write file, message was: " + e.getMessage(), e);
sftpUtil.setErrorOccurredOnInputStream(inputStream);
if (useTempDir)
{
// Cleanup the remote temp dir from the not fullt completely
// transferred file!
String tempDir = sftpUtil.getTempDirOutbound();
sftpUtil.cleanupTempDir(client, transferFilename, tempDir);
}
throw e;
}
finally
{
if (client != null)
{
// If the connection fails, the client will be null, otherwise
// disconnect.
connector.releaseClient(endpoint, client);
}
inputStream.close();
}
}
private InputStream generateInputStream(MuleEvent event)
{
Object data = event.getMessage().getPayload();
// byte[], String, or InputStream payloads supported.
byte[] buf;
InputStream inputStream;
if (data instanceof byte[])
{
buf = (byte[]) data;
inputStream = new ByteArrayInputStream(buf);
}
else if (data instanceof InputStream)
{
inputStream = (InputStream) data;
}
else if (data instanceof String)
{
inputStream = new ByteArrayInputStream(((String) data).getBytes());
}
else
{
throw new IllegalArgumentException(
"Unexpected message type: java.io.InputStream, byte[], or String expected. Got "
+ data.getClass().getName());
}
return inputStream;
}
private String buildFilename(MuleEvent event)
{
MuleMessage muleMessage = event.getMessage();
String outPattern = (String) endpoint.getProperty(SftpConnector.PROPERTY_OUTPUT_PATTERN);
if (outPattern == null)
{
outPattern = (String) muleMessage.getProperty(SftpConnector.PROPERTY_OUTPUT_PATTERN, connector.getOutputPattern());
}
String filename = connector.getFilenameParser().getFilename(muleMessage, outPattern);
if (filename == null)
{
filename = (String) event.getMessage().findPropertyInAnyScope(SftpConnector.PROPERTY_FILENAME,
null);
}
return filename;
}
protected MuleMessage doSend(MuleEvent event) throws Exception
{
doDispatch(event);
return event.getMessage();
}
}
該類的唯一重要的部分是在構造函數中，構建自定義SFTP UTIL：
public class CustomSftpUtil extends SftpUtil {
private SftpConnector connector;
private MuleContext context;
public CustomSftpUtil(ImmutableEndpoint endpoint) {
super(endpoint);
connector = (SftpConnector) endpoint.getConnector();
context = endpoint.getMuleContext();
handleIdentityFile();
handlePassphrase();
}
private void handleIdentityFile() {
String evaluatedExpression = evaluateMelExpression(connector.getIdentityFile());
connector.setIdentityFile(evaluatedExpression);
}
private void handlePassphrase() {
String evaluatedExpression = evaluateMelExpression(connector.getPassphrase());
connector.setPassphrase(evaluatedExpression);
}
private String evaluateMelExpression(String melExpression) {
return context.getExpressionManager().evaluate(melExpression, RequestContext.getEvent()).toString();
}
}
這個類的唯一重要的部分是身份文件的評估（和口令）作爲MEL表達式，這允許我們通過MEL表達式動態設置身份文件和密碼。