Mark, Take a look at the replaceAll function. Juan is correct you will want to use UpdateAttribute in the advance mode.
https://nifi.apache.org/docs/nifi-docs/html/expression-language-guide.html#replaceall Ryan On Wed, Nov 4, 2015 at 6:52 AM, Juan Jose Escobar < [email protected]> wrote: > > Hello, Mark, > > I think it should be possible to do it using UpdateAttribute in advanced > mode: define a condition for each of the different formats, and once the > particular format type is identified, get the appropriate substring into a > new attribute - or into the filename attribute if you want to normalize > naming. If I remember correctly, there is no support to extract the regex > groups in Nifi Expression Language in 0.3.0. > > Hope this helps > > J > > On Wed, Nov 4, 2015 at 7:04 AM, Mark Petronic <[email protected]> > wrote: > >> Looking for some help on best way to extract a field from a filename. I >> need to parse out the date from the core filename attribute set by the >> UnpackContent processor. I am unzipping files that contain many CSV files >> and these CSV file names vary in format but each has a timestamp included >> in the filename. Example formats are: >> >> Priority_002_20151104123456_00.csv (20151104123456 is yyyyMMddHHmmss) >> ABC_02_1447586912344.csv (1447586912344 is Unix time in ms) >> XYZ_20151104_1234.csv (20151104_1234 is yyyyMMdd_HHmm) >> >> So, there are various forms to deal with. I need to normalize these into >> yyyyMMddHHmmss. A regex with capture groups would be perfect but I cannot >> quite figure out how to do it. ExtractText does regex with capture groups >> but only against flowfile contents and these are attributes. >> UpdateAttribute only support expression language and that does not have >> regex based extracts of capture groups. >> >> In Python, I would just do something like: >> >> date, time = re.search(r"XYZ_(\d+)_(\d+)\.csv", >> "XYZ_20151104_1234.csv").groups() >> >> Then I could use the expression language format or doDate functions to >> normalize the dates >> >> I know I could use a utility script with ExecuteStreamCommand that I >> could call with the filepath and get back the tokens but was looking for an >> internal way to do it without forking out as there are a lot of archives in >> each zip and that would add to latency in heavy loads. >> >> Any thoughts? >> >> Thanks! >> >> >
