NiFi: Understanding Core FlowFile Attributes: Accessing fileSize and filename in NiFi

[#1]

How to capture the filesize and the filename, which can be found in the details section of the flowfile? I understand that the filename is listed in the attribute section, but is there a way to know the variable name for filesize?

kafka-flow-file.jpg

[#2]

I don't know of any out of box functionality to get file size. You can use the execute script to and script up way to easily grab the file size. Or build a processor to grab content size. Here is what the code for the processor would look like. very simple.

@Override
public void onTrigger(final ProcessContext context, final ProcessSession session) throws ProcessException {
    final ComponentLog log = getLogger();
    final AtomicReference<String> value = new AtomicReference<>();

    FlowFile flowfile = session.get();

    session.read(flowfile, new InputStreamCallback() {
        @Override
        public void process(InputStream in) throws IOException {
            try{

                String outputHandler = context.getProperty(OUTPUTHANDLER).getValue();


                String stringToTest = IOUtils.toString(in);

                // Check length, in characters if that is what you want
                System.out.println(stringToTest.length()); // prints "11"

                // Or provided specific encoded sizes ie UTF-8. this can be property driven
                //String result = stringToTest.getBytes("UTF-8").toString();

                value.set(result);
            }catch(Exception ex){
                ex.printStackTrace();

[#3 · Accepted solution]

@kumar

The default FlowFile attributes include:

entryDate

lineageStartDate

fileSize

filename

path

uuid

The above FlowFile attribute key names are case sensitive.

Thanks,

Matt

[#4]

Thank you, that was it! It would good if they get listed in the Attribute tab as well.