# Logstash: Custom filter reading CSV
**URL:** https://discuss.elastic.co/t/logstash-custom-filter-reading-csv/38302
**Category:** Logstash
**Created:** [January 4, 2016, 9:52am UTC](https://discuss.elastic.co/t/logstash-custom-filter-reading-csv/38302 "2016-01-04T09:52:54Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@krushnat\_khawale](https://discuss.elastic.co/u/krushnat_khawale)
#### Post date: [January 4, 2016, 9:52am UTC](https://discuss.elastic.co/t/logstash-custom-filter-reading-csv/38302/1 "2016-01-04T09:52:54Z")
In my use case, I need to upload data into the logstash and simultaniously need to check the data based on another file. For this reason, I need to read mapping file at once and to validate against data.
I am writing my own filter.
Suggest solution.
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### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [January 4, 2016, 10:14am UTC](https://discuss.elastic.co/t/logstash-custom-filter-reading-csv/38302/2 "2016-01-04T10:14:01Z")
Hard to suggest much without additional details, but it sounds like the translate filter could help you. If you want a more specific answer you'll have to ask a more specific question.
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 5:16am UTC](https://discuss.elastic.co/t/logstash-custom-filter-reading-csv/38302/3 "2017-07-06T05:16:59Z")