I’ve entered a Jira issue, NIFI-1660, to enhance the expression language to be able to evaluate a Json path. I plan on submitting a pull request on it in the next week or so.
On 3/22/16, 2:53 AM, "Conrad Crampton" <conrad.cramp...@secdata.com> wrote: >My 2p. >If the kaka.key value (very simple json), you could use UpdateAttribute and >use some expression language - specifically the string manipulation functions >to extract the part you want. >I like the power or ExecuteProcessor by the way. > >And I agree, this community is phenomenally responsive and helpful. > >Regards >Conrad > > > > >On 21/03/2016, 18:38, "McDermott, Chris Kevin (MSDU - STaTS/StorefrontRemote)" ><chris.mcderm...@hpe.com> wrote: > >>Thanks everyone. While I’m naturally disappointed that this doesn’t exist, I >>am hyper charged about the responsiveness and enthusiasm of the NiFi >>community! >> >>From: Matt Burgess <mattyb...@gmail.com<mailto:mattyb...@gmail.com>> >>Reply-To: "users@nifi.apache.org<mailto:users@nifi.apache.org>" >><users@nifi.apache.org<mailto:users@nifi.apache.org>> >>Date: Monday, March 21, 2016 at 1:58 PM >>To: "users@nifi.apache.org<mailto:users@nifi.apache.org>" >><users@nifi.apache.org<mailto:users@nifi.apache.org>> >>Subject: Re: Help on creating that flow that requires processing attributes >>in a flow content but need to preserve the original flow content >> >>One way (in NiFi 0.5.0+) is to use the ExecuteScript processor, which gives >>you full control over the session and flowfile(s). For example if you had >>JSON in your "kafka.key" attribute such as "{"data": {"myKey": "myValue"}}" , >>you could use the following Groovy script to parse out the value of the >>'data.myKey' field: >> >>def flowfile = session.get() >>if(!flowfile) return >>def json = new >>groovy.json.JsonSlurper().parseText(flowfile.getAttribute('kafka.key')) >>flowfile = session.putAttribute(flowfile, 'myKey', json.data.myKey) >>session.transfer(flowfile, REL_SUCCESS) >> >> >>I put an example of this up as a Gist >>(https://gist.github.com/mattyb149/478864017ec70d76f74f) >> >>A possible improvement could be to add a "jsonPath" function to Expression >>Language, which could take any value (including an attribute) along with a >>JSONPath expression to evaluate against it... >> >>Regards, >>Matt >> >>On Mon, Mar 21, 2016 at 1:48 PM, McDermott, Chris Kevin (MSDU - >>STaTS/StorefrontRemote) >><chris.mcderm...@hpe.com<mailto:chris.mcderm...@hpe.com>> wrote: >>Joe, >> >>Thanks for the reply. I think I was not clear. >> >>The JSON I need to evaluate is in a FlowFile attribute (kafka.key) which I >>need to be able to evaluate without modifying the original FlowFile content >>(which was read from the Kafka topic). What I can’t figure out is how to >>squirrel away the flowfile content so that I can write the value of the >>kafka.key attribute to the FlowFile content, so that I can process it with >>EvaluateJsonPath, and then read content I squirreled away back into the >>FlowFile content. I considered using the the DistributedMapCache, but there >>would be no guarantee what I added to the cache would still be there when I >>needed it back. >> >> >> >> >>On 3/21/16, 1:37 PM, "Joe Witt" >><joe.w...@gmail.com<mailto:joe.w...@gmail.com>> wrote: >> >>>Chris, >>> >>>Sounds like you have the right flow in mind already. EvaluateJSONPath >>>does not write content. It merely evaluates the given jsonpath >>>expression against the content of the flowfile and if appropriate >>>creates a flowfile attribute of what it finds. >>> >>>For example if you have JSON from Twitter you can use EvaluateJsonPath >>>and add a property with a name >>>'twitter.user' and a value of '$.user.name<http://user.name>' >>> >>>Once you run the tweets through each flow file will have an attribute >>>called 'twitter.user' with the name found in the message. No >>>manipulation of content at all. Just promotes things it finds to flow >>>file attributes. >>> >>>Thanks >>>Joe >>> >>>On Mon, Mar 21, 2016 at 1:34 PM, McDermott, Chris Kevin (MSDU - >>>STaTS/StorefrontRemote) >>><chris.mcderm...@hpe.com<mailto:chris.mcderm...@hpe.com>> wrote: >>>> What I need to do is read a file from Kafka. The Kafka key contains a >>>> JSON string which I need to turn in FlowFile attributes while preserving >>>> the original FlowFile content. Obviously I can use EvaluteJsonPath but >>>> that necessitates replacing the FlowFile content with the kaka.key >>>> attribute, thus loosing the original FlowFile content. I feel like I’m >>>> missing something fundamental. >> >> >> >> ***This email originated outside SecureData*** >> >>Click https://www.mailcontrol.com/sr/MZbqvYs5QwJvpeaetUwhCQ== to report this >>email as spam. > > >SecureData, combating cyber threats >______________________________________________________________________ >The information contained in this message or any of its attachments may be >privileged and confidential and intended for the exclusive use of the intended >recipient. If you are not the intended recipient any disclosure, reproduction, >distribution or other dissemination or use of this communications is strictly >prohibited. The views expressed in this email are those of the individual and >not necessarily of SecureData Europe Ltd. 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