You can accomplish this with ExecuteScript, the following example uses Groovy as the language and Jayway's JsonPath as the library for JSONPath parsing. First I had to download 3 JARs (json-path and its required transitive dependencies) into a directory:
Then I set the Module Directory property to the path of this directory:
Note that I have also added a dynamic property, whose name will become an attribute and whose value supports Expression Language and (after evaluation) should contain a JSONPath expression used to retrieve the value from the content of the JSON flow file.
The Script Body is the following Groovy script:
import com.jayway.jsonpath.*
def flowFile = session.get()
if(!flowFile) return
def inputStream = session.read(flowFile)
def json = JsonPath.parse(inputStream)
inputStream.close()
context.properties.findAll {p,s -> p.dynamic}.each {pd, name ->
def prop = context.getProperty(pd)
try {
flowFile = session.putAttribute(flowFile, pd.name, json.read(prop.evaluateAttributeExpressions(flowFile).value))
} catch (e) {
log.error("Error evaluating JSONPath expression in property $name: ${prop?.value} , ignoring...", e)
}
}
session.transfer(flowFile, REL_SUCCESS)I tested this with a GenerateFlowFile:
After the ExecuteScript transfers the flow file, it has the desired attribute name/value:
This should work with any number of attributes/JSONPaths per flow file. In addition, I have written NIFI-4100 to cover the improvement to the EvaluateJsonPath processor to support Expression Language.
