# Using logstash+http\_poller to loop through JSON structure, run 2nd poller
**URL:** https://discuss.elastic.co/t/using-logstash-http-poller-to-loop-through-json-structure-run-2nd-poller/109121
**Category:** Logstash
**Created:** [November 26, 2017, 6:29am UTC](https://discuss.elastic.co/t/using-logstash-http-poller-to-loop-through-json-structure-run-2nd-poller/109121 "2017-11-26T06:29:38Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@dorj1234](https://discuss.elastic.co/u/dorj1234)
#### Post date: [November 26, 2017, 6:29am UTC](https://discuss.elastic.co/t/using-logstash-http-poller-to-loop-through-json-structure-run-2nd-poller/109121/1 "2017-11-26T06:29:38Z")
Hello,
I have an http\_poller working and getting me an array of JSON structures.
Is it possible in logstash to loop through one of the fields and for each one run a second http\_poller?
For example, let's say my structure has a "City" field. I would like to run a second REST API for each city. Can it be done without hitting ruby coding? or if I must use ruby - can you point me in the right direction on how ruby does JSON parsing?
Or for ruby, how do I extract the "City" value from this json structure and then call a second http\_poller with that value as part of my URL?
{
"City" : "Frankfurt",
"Population" : "12345",
"Some stat" : "10"
},
{
"City" : "New York",
"Population" : "123456",
"Some stat" : "100"
}
HTTP poller will run for each city in the "loop":
...
URL =\> { "https://...../%[current\_city\_field]" }
...
Thanks in advance !
JD
---
### Author:  [@magnusbaeck](https://discuss.elastic.co/u/magnusbaeck)
#### Post date: [November 27, 2017, 6:30am UTC](https://discuss.elastic.co/t/using-logstash-http-poller-to-loop-through-json-structure-run-2nd-poller/109121/2 "2017-11-27T06:30:05Z")
> Is it possible in logstash to loop through one of the fields and for each one run a second http\_poller?
Not with an http\_poller _input_, but if there were a _filter_ with the same features as http\_poller perhaps it would be possible. Right now you'll have to write some Ruby code, either in a ruby filter or in a plugin. If you deserialize the JSON in the HTTP response by using a json codec in the http\_poller input you won't have to worry about JSON deserialization in the ruby filter.
A possible option, if you're able to periodically dump all the city mappings into a flat file, is to use a translate filter.
---
### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [December 25, 2017, 6:30am UTC](https://discuss.elastic.co/t/using-logstash-http-poller-to-loop-through-json-structure-run-2nd-poller/109121/3 "2017-12-25T06:30:34Z")
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