如何使用 NiFi 将字符串转换为 JSON 数组

Question

In NiFi I'm processing a flowfile containing the following attribute:

Key: 'my_array'
    Value: '[u'firstElement', u'secondElement']'

I'd like to split flowFile on this array to process each element separately (and then merge). I tried to use SplitJson processor, but it requires JSON content to operate on, so I used AttributesToJSON before it. Unfortunately the produced flowFile's content is:

{"my_array": "[u'firstElement', u'secondElement'"}

And I receive the error

The evaluated value [u'firstElement', u'secondElement'] of $['my_array'] was not a JSON Array compatible type and cannot be split.

Is it possible to convert my_array string to the correct JSON array? Do I need to use ExecuteScript or is there some simpler way?

Answer 1

How about ReplaceText with Replacement Strategy of Always Replace and Replacement Value of ${my_array} and then SplitJSON ? This will replace your FlowFile's content with this attribute's value and then you could SplitJSON on it.

Answer 2

Suppose I want to string : "Hashtags": "['tag1','tag2']" (a s part of my resultant json in Nifi, ) to be changed into : "Hashtags": ['tag1','tag2'].

what I do is :

I use ReplaceText with Replacement Strategy : Regex Replace and Replacement Value : a regex Expression . This will replace FlowFile's matched content with this attribute's value and then you could continue your process.