Transmitting an RoCrate instance over a network about ro-crate-java

[Pfeil]

Hi Stuart,

if your plan is to send only the linked data document (the content of ro-crate-metadata.json), you can get this content as a String using this method: String edu.kit.datamanager.ro_crate.Crate.getJsonMetadata(). Does this fit your use case?

In case you have an application which makes use of the Writer classes in ro-crate-java anyway, the WriterStrategy interface may be of interest to handle sending similarly to writing to a folder or zip file.

I hope this helps. If you see something is missing, or I misunderstood your use case, please do not hesitate to ask again. :)

[StuartWheater]

Hi Andreas,
My ultimate goal is to pass an RoCrate between to independent organization, as a AMQP message. The messages representing an invocation of an analysis service, both requests and responds. I don't think just the metadata will be sufficient, but I will check.

I will look at modifying Writer class to create an in-memory Zip or BagIt.

Stuart

[Pfeil]

In this case, the ZipWriter class will help you to understand the process of generating a valid zipped crate. The zip library we use does not seem to have any in-memory features at first glance, but you are of course not restricted to this library. As a workaround, it may be useful to write it to a temporary directory before reading it again for transmission.

Is your scenario limited to rather small crates? Sending AMQP messages with crates of multiple gigabytes may be not too practical. In such cases, I could imagine to work around this by storing the crate in a repository and distributing a link (and maybe required credentials or so, depending on the scenario) via the message.

Reading this possibly outdated statement and the references given in it, I would not send messages with more than 100mb, although I have no practical experience with large messages, and it may depend on the message broker you use.

[StuartWheater]

Thank you. Yes the request and responses are expected to be relatively small, as the analysis is being performed at the data. The AMQP size restrictions shouldn't be an issue.

[Pfeil]

You're welcome. I see, so this will be no issue on your side. I'll close the issue for now. If you have any other question, feel free to open another issue or reopen this one. Thanks!