How to return content from a custom DFS service

Sander Hendriks

Hi,

I'm working on a custom DFS service that should do the following:

- get some content files from the repository

- create a ZIP file with all those content files

- return the ZIP file to the service consumer

I'm stuck on the last bit. How can I return a file to the consumer?

Since the ZIP file is created on the fly locally on the DFS server, it is not in the repository.

This means that UCF and ACS cannot be used.

So how can I do this? Streaming should be used, since the file could be in Gb size.

THanks for any help,

Sander

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rohit0212

HI Sander,

code goes like this:::::

ContentTransferProfile transferProfile = new ContentTransferProfile();

transferProfile.setGeolocation(geoLoc);

transferProfile.setTransferMode(transferMode);

serviceContext.setProfile(transferProfile);

ContentProfile contentProfile = new ContentProfile();

contentProfile.setFormatFilter(FormatFilter.ANY);

contentProfile.setUrlReturnPolicy(UrlReturnPolicy.PREFER);

OperationOptions operationOptions = new OperationOptions();

operationOptions.setContentProfile(contentProfile);

operationOptions.setProfile(contentProfile);

ObjectIdentitySet objectIdSet = new ObjectIdentitySet();

List<ObjectIdentity> objIdList = objectIdSet.getIdentities();

objIdList.add(objectIdentity);

DataPackage dataPackage = objectService.get(objectIdSet, operationOptions);

DataObject dataObject = dataPackage.getDataObjects().get(0);

Content resultContent = dataObject.getContents().get(0);

Pass the objectIdentity .... and once you get the Content , you can get file as well

by using resultContent.getAsFile()

aflowers001

Unfortunately you're a little stuck here. DFS provides 3 basic methods to return content, BASE64, MTOM or UCF.

Now BASE64 can quickly be dismissed.

MTOM can be used but you'd have to look into the sizes and the client and the potential for timeouts

For UCF I believe that there is something you might be able to do, but it might noit be possible. Basically you return a URL that UCF can pick up and have that URL act like a UCF/ACS end point.

It might be worth considering a custom solution whereby, if you know the client, you return a URL as part of the data and have the client decide to request the data via that. This URL will be of your own design pointing to your own end point, but you'd have to remember to have code to clean up, especially if you have multi GB size files generated.

You could also consider creating the ZIP file within the repsoitory and thus allowing ACS to be used?

Sander Hendriks

Hi Rohit,

thanks for your reply, though I don't think this will work, since the content file my service needs to return is not in the repository. There is no object that the ObjectIdentity can point to to get its content.

My service has the ZIP file that it needs to return stored locally. All I need to figure out is how to send it to the client (the service consumer).

I would like to do whatever the DFS ObjectService does when it sends over a content file to its consumer. Unfortunately I can only find examples for consumer code, not provider code. The 'Writing custom services' chapter in the DFS Developer Guide is no help for returning content either. It only mentions different kinds of metadata (properties, relations, permissions etc), not content.

Could it be as simple as returning a byte[] from your custom service class and then hope that the DFS PL will turn it into an MTOM stream? I'll try that out today.

More ideas are welcome.

Sander

Sander Hendriks

Hi Andy,

Thanks for helping me out.

I did indeed consider storing the ZIP file inthe repository. However that would mean moving the (possibly large) content over the network 3 times:

1 - Download all content from the CS to the DFS server

2 - Store the ZIP file in the repo on the CS

3 - Download the ZIP file to the client

When my service just returns the ZIP file to the client directly, that would save some time and network traffic. It would also mean that the repository is not polluted with temporary content that needs to be cleaned out regularly.

All I need to do now is find out how to stream content from a custom DFS service to its consumer.

any more ideas?

Sander