Question

I am looking for the best solution for custom file parsing for our enterprise import routines. I want to basically change one file format into a standard file format and have one routine that imports that data into the database. I need to be able to create custom scripts for each client since its difficult to get the customer to comply with a standard or template format. I have looked at PowerShell and Iron Python to do this so far but I am not sure this is the route I want to go. I have also looked at some tools such as Talend which is a drag and drop style tool which may or may not give me what I want as far as flexibility. We are a .NET shop and have created custom code to do this in the past but I need something that is quicker to create then coding custom parsing functions each time we get a new file format in.

Answer 1

Python is wonderful for this kind of thing. That’s why we use. Each new customer transfer is a new adventure and Python gives us the flexibility to respond quickly.

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Edit. All python scripts that read files are “custom file parsers”. Without an actual example, it’s not sensible to provide a detailed example.

with open( "some file", "r" ) as source:
    for line in source:
        process( line )

That’s about all there is to a “custom file parser”. If you’re parsing .csv or .xml files, then Python has modules for that. If you’re parsing fixed-format files, you’d use string slicing operations. If you’re parsing other files (X12? JSON? YAML?) you’ll need appropriate parsers.

Tab-Delim.

from collections import namedtuple
RecordLayout = namedtuple('RecordLayout',['field1','field2','field3',...])
def process( aLine ):
    record = RecordLayout( aLine.split('\t') )
    ...

Fixed Layout.

from collections import namedtuple
RecordLayout = namedtuple('RecordLayout',['field1','field2','field3',...])
def process( aLine ):
    fields = ( aLine[:10], aLine[10:20], aLine[20:30], ... )
    record = RecordLayout( fields )
    ...