# Flatten recursively a JSON to Logstash in Ruby

**URL:** <https://discuss.elastic.co/t/flatten-recursively-a-json-to-logstash-in-ruby/188076>\
**Category:** Logstash\
**Created:** [June 28, 2019, 3:13pm UTC](https://discuss.elastic.co/t/flatten-recursively-a-json-to-logstash-in-ruby/188076 "2019-06-28T15:13:14Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**Author:** ![Badger](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/badger/32/25190_2.png) [@Badger](https://discuss.elastic.co/u/Badger)\
**Post date:** [June 28, 2019, 4:03pm UTC](https://discuss.elastic.co/t/flatten-recursively-a-json-to-logstash-in-ruby/188076/2 "2019-06-28T16:03:40Z")

</div>

I cannot think of a way to do what you want. The problem is that you want to replace an array with additional hash entries. That appears to require knowing where you are in the event although it is conceivable there is a way to do a merge into the parent field.

The closest I can get is this

```
def register(params)
    @field = params['field']
end

def processArray(a)
    newHash = {}
    a.each_index { |x|
        newHash["entry#{x}"] = processObject(a[x])
    }
    newHash
end

def processHash(h)
    newHash = {}
    h.each { |k, v|
        newHash[k] = processObject(v)
    }
    newHash
end

def processObject(v)
    if v.kind_of?(Array)
        processArray(v)
    elsif v.kind_of?(Hash)
        processHash(v)
    else
        v
    end
end

def filter(event)
    v = event.get(@field)
    if v
        event.remove(@field)
        event.set(@field, processObject(v))
    end
    [event]
end

```

which you would invoke using

```
    ruby {
        path => "/home/user/Ruby/FlattenArrays.rb"
        script_params => { "field" => "payload" }
    }

```

and it will produce

```
   "payload" => {
    "entry0" => {
               "route" => "/v1/things",
              "method" => "PUT",
        "content-type" => "json",
                "body" => {
            "licencePlate" => "ZZ123ZZ"
        },
              "status" => 200
    },
    "entry1" => {
               "route" => "/v2",
              "method" => "DEL",
        "content-type" => "html",
                "body" => {
            "entry0" => {
                "plate" => "67S8DFSDF125V-952",
                "infos" => "diverse"
            },
            "entry1" => {
                "plate" => "DZEC12CD-856"
            }
        },
              "status" => 400
    }
},
```

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