Using flowfile size as an argument in RouteOnAttribute nifi

Question

I want to know if is it possible to use flowfile size as an argument in routeOnAttribute i want to make expression like that :

${filename.fileSize>500}

but it tells me that expression ought to return true and my expression returns string what should i do to be able to make new connection in routeOnAttribute(p.s filename is my flowfile name)

EDIT 05/17/2019 Correct answer is Andy's. That is the best guidance from us (Apache NiFi team) on the subject. The answer marked "correct" only applies in a few cases where Content-Length is set by an upstream processor. Andy's solution, fileSize is universally applicable.

Why you are comparing file Size?.FileSize is not an attribute in which you use. — Mister X, Aug 24 '17 at 06:47
I want to check if the flowfile size is less than 500( it means response is empty) and i can make connection with emty reponse and then log it. should i use conetn size instead of size ? — Sagitarius, Aug 24 '17 at 06:53
ok thank you I have made it like this ${Content-Length:toNumber():divide(500):equals(1)} — Sagitarius, Aug 24 '17 at 07:31

Andy · Answer 1 · 2017-08-24T19:15:17.997

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Your expression is logically correct but does not use valid Apache NiFi syntax. It should use the gt function as below:

${fileSize:gt(500)}

This will return a boolean result.

edited Aug 24 '17 at 19:15

answered Aug 24 '17 at 19:00

Andy

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score 0 · Answer 2 · answered Feb 14 '22 at 20:12

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On the RouteOnAttribute, you can configure an attribute whose value evaluates to true when flowfile content is of certain size.

answered Feb 14 '22 at 20:12

Vijay Kumar

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score -2 · Accepted Answer · answered Aug 24 '17 at 08:37

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Two ways to check empty response present in flowfile.

1.Using Content-Length attribute-->${Content-Length}

2.Using Extract Text processor to extracts entire content in attribute.

flow_content--(.*)

then check ${flow_content:isEmpty():not()}

It may be helpful for your case.

answered Aug 24 '17 at 08:37

Mister X

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It is far preferable to use `${Content-Length}` because extracting the content to an attribute when the content is large will have a very detrimental effect on the performance of the application. Attributes are held in memory and written to the flowfile repository, which is designed for fast read/write and lightweight data. It is highly discouraged to extract the entire flowfile contents to an attribute just to check the size. – Andy Aug 24 '17 at 18:55

Using flowfile size as an argument in RouteOnAttribute nifi

3 Answers3