Need a non null response from SFTP outbound adapter

[jackrabbit]

Hi everyone,

I'm trying to get feedback of any kind from a SFTP outbound adapter without any luck.
I understand that this is by design, however, I want to be able to tell whether the adapter was successful sending the files to its destination and propagate this message to the gateway's calling call.
Is that possible?
If not, can you recommend a new approach to get a response for a SFTP PUT operation?

Thanks.

[Gary Russell]

On technique is to make the final channel (before the outbound adapter) a <publish-subscribe-channel/> subscribe the adapter (order="1") and a <transformer/> (order="2").

The transformer will only get the message if the sftp put was successful; you can transform the message to a result, and send it wherever you like.

[jackrabbit]

following your advice, I'm having a bit of a problem with the message to send:
The SFTP outbound adapter requires a java.io.File type of message, while the transformer requires another object.
Is it possible to send different type of messages to different subscribers? or alternatively, pass the outbound adapter (using expression perhaps) just the relevant portion of payload which contain the file to be put?

[Gary Russell]

I am not sure I understand what you mean by

while the transformer requires another object

A transformer can transform anything to anything - you can even ignore the actual inbound payload if you want. Try

<transformer input-channel="in" output-channel="out" expression="ok"/>

or

<transformer input-channel="in" output-channel="out" expression="payload.absolutePath + ' processed ok'"/>

[jackrabbit]

Let me try to explain by code:

<!-- Submit the file to supplier -->
<integration:publish-subscribe-channel id="notifysupplier"/>

<int-sftp:outbound-channel-adapter id="supplierSecuredFileTransfer"
								   session-factory="sftpSessionFactory"
								   channel="notifysupplier"
								   remote-filename-generator-expression="cancellations.TKT"
								   remote-directory="/var/tmp"
								   order="1" />
								   
<!-- Delete the notification records marked as successful -->
<integration:service-activator id="deleteNotificationRecords" 
							   input-channel="notifysupplier" 
							   ref="supplierDatabaseService" 
							   method="removeNotificationEntries"
							   order="2"/>

Messages sent to the channel "notifySupplier" must be of the types java.io.File, String or byte[] for the consumption of the SFTP outbound adapter (supplierSecuredFileTransfer), while I need a different Message type to be passed to the service-activator (deleteNotificationRecords). Is that clearer?

[Gary Russell]

You just need to add a transformer before deleteNotificationRecords to create a payload that will match the method signature for removeNotificationEntries?

<int:transformer input-channel="notifysupplier" output-channel="finalNotify" 
    order="2"
    expression="something to change the payload to match the signature"/>

<integration:service-activator id="deleteNotificationRecords" 
							   input-channel="finalNotify" 
							   ref="supplierDatabaseService" 
							   method="removeNotificationEntries"/>

[jackrabbit]

The order here matters. outbound adapter should run first, therefore "notifysupplier" should get a File payload.
The service-activator (deleteNotificationRecords) which runs afterwards (order="2") requires a different object as payload (which the File is a part of it).

What would be great if I can apply a similar logic like the one you suggested and place the transformer first passing the File to the adapter, while the service-activator gets the larger payload message.

[Gary Russell]

Well, then reverse the logic and put the transformer before the adapter instead.

<integration:publish-subscribe-channel id="notifysupplier"/>

<int:transformer input-channel="notifysupplier" output-channel="toFTP" 
    order="1"
    expression="payload.file"/> <!-- assumes your big object has a method getFile() -->

<int-sftp:outbound-channel-adapter id="supplierSecuredFileTransfer"
						   session-factory="sftpSessionFactory"
						   channel="toFTP"
						   remote-filename-generator-expression="cancellations.TKT"
						   remote-directory="/var/tmp"/>
								   
<!-- Delete the notification records marked as successful -->
<integration:service-activator id="deleteNotificationRecords" 
							   input-channel="notifysupplier" 
							   ref="supplierDatabaseService" 
							   method="removeNotificationEntries"
                                                           order="2"/>

The big object will FIRST (order=1) be sent to the transformer, transformed to a File and sent to FTP; if successful, the big object will then be sent to the <service-activator/> (order=2).

[jackrabbit]

Is the output-channel of the transformer correct? Shouldn't it point to the adapter (supplierSecuredFileTransfer)?

Not sure how you should wire the adapter. On one hand it needs to adapt the notifysupplier channel (input-channel="notifysupplier"), and on the other hand it should be wired to the transformer to get the 'reduced' payload (input-channel=transformer-id).

Is that correct?

[Gary Russell]

Yes, sorry - I just fixed it, the transformer output-channel is the adapter's input channel.