Get String from Spring FTP streaming Inbound Channel Adapter - spring

Question

I have the following code which works OK retrieving files from FTP server into a stream, but I need to get String of each file, seems I need to use the Transformer passing a charset but what I'm missing? How exactly to get the content String of each file transferred?
Thanks a lot in advance
#SpringBootApplication
#EnableIntegration
public class FtpinboundApp extends SpringBootServletInitializer implements WebApplicationInitializer {
final static Logger logger = Logger.getLogger(FtpinboundApp.class);
public static void main(String[] args) {
SpringApplication.run(FtpinboundApp.class, args);
}
#Bean
public SessionFactory<FTPFile> ftpSessionFactory() {
DefaultFtpSessionFactory sf = new DefaultFtpSessionFactory();
sf.setHost("X.X.X.X");
sf.setPort(21);
sf.setUsername("xxx");
sf.setPassword("XXX");
return new CachingSessionFactory<FTPFile>(sf);
}
#Bean
#ServiceActivator(inputChannel = "stream")
public MessageHandler handler() {
return new MessageHandler() {
#Override
public void handleMessage(Message<?> message) throws MessagingException {
System.out.println("trasnferred file:" + message.getPayload());
}
};
}
#Bean
#InboundChannelAdapter(value = "stream", poller = #Poller(fixedRate = "1000"))
public MessageSource<InputStream> ftpMessageSource() {
FtpStreamingMessageSource messageSource = new FtpStreamingMessageSource(template(), null);
messageSource.setRemoteDirectory("/X/X/X");
messageSource.setFilter(new FtpPersistentAcceptOnceFileListFilter(new SimpleMetadataStore(), "streaming"));
return messageSource;
}
#Bean
#Transformer(inputChannel = "stream", outputChannel = "data")
public org.springframework.integration.transformer.Transformer transformer() {
return new StreamTransformer("UTF-8");
}
#Bean
public FtpRemoteFileTemplate template() {
return new FtpRemoteFileTemplate(ftpSessionFactory());
}
#Bean(name = PollerMetadata.DEFAULT_POLLER)
public PollerMetadata defaultPoller() {
PollerMetadata pollerMetadata = new PollerMetadata();
pollerMetadata.setTrigger(new PeriodicTrigger(5000));
return pollerMetadata;
}
}

Answer 1

Use a StreamTransformer to get the whole file as a single string, or a FileSplitter to get a message for each line.
EDIT (filter config)
#Bean
#InboundChannelAdapter(channel = "stream")
public MessageSource<InputStream> ftpMessageSource() {
FtpStreamingMessageSource messageSource = new FtpStreamingMessageSource(template(), null);
messageSource.setRemoteDirectory("ftpSource/");
messageSource.setFilter(filter());
return messageSource;
}
public FileListFilter<FTPFile> filter() {
CompositeFileListFilter<FTPFile> filter = new CompositeFileListFilter<>();
filter.addFilter(new FtpSimplePatternFileListFilter("*.txt"));
filter.addFilter(acceptOnceFilter());
return filter;
}
#Bean
public FtpPersistentAcceptOnceFileListFilter acceptOnceFilter() {
FtpPersistentAcceptOnceFileListFilter filter = new FtpPersistentAcceptOnceFileListFilter(meta(),
"streaming"); // keys will be, e.g. "streamingfoo.txt"
filter.setFlushOnUpdate(true);
return filter;
}
#Bean
public ConcurrentMetadataStore meta() {
PropertiesPersistingMetadataStore meta = new PropertiesPersistingMetadataStore();
meta.setBaseDirectory("/tmp/foo");
meta.setFileName("ftpStream.properties");
return meta;
}
EDIT2 - remove remote file with an advice
#ServiceActivator(inputChannel = "data", adviceChain = "after")
#Bean
public MessageHandler handle() {
return System.out::println;
}
#Bean
public ExpressionEvaluatingRequestHandlerAdvice after() {
ExpressionEvaluatingRequestHandlerAdvice advice = new ExpressionEvaluatingRequestHandlerAdvice();
advice.setOnSuccessExpression(
"#template.remove(headers['file_remoteDirectory'] + headers['file_remoteFile'])");
advice.setPropagateEvaluationFailures(true);
return advice;
}