Thanks for the explanation!
On Mon, Jan 16, 2017 at 12:24 PM, Joe Percivall <[email protected]>
wrote:
> Nick,
>
> A main reason why content isn't referenceable by expression language is
> that it promotes an anti-pattern. Reading the content takes significantly
> more time than attributes and should be limited as much as possible. Also
> content can potentially be very large and reading the entire thing in
> memory can cause many adverse effects.
>
> Having less processors does not mean the flow is better (similar to
> concise code != efficient code). You can have a couple very specialized
> processors that very effectively stream the content and do operations as
> needed. Alternatively using EL to grab the content each time ${content()}
> is called would introduce many processors worth of memory and IO
> inefficiency.
>
> You can learn more about the different repositories by reading this doc[1].
>
> [1] https://nifi.apache.org/docs/nifi-docs/html/nifi-in-depth.html
>
> Joe
>
> On Mon, Jan 16, 2017 at 3:15 PM, Nick Carenza <
> [email protected]> wrote:
>
>> I found a section in the nifi expression language documentation of
>> Subjectless Functions. Could/should this feature be added as one of those?
>>
>> On Mon, Jan 16, 2017 at 11:53 AM, Nick Carenza <
>> [email protected]> wrote:
>>
>>> Thanks Bryan, that is what I ended up doing. PutEmail works the same was
>>> as PutSlack in this regard. It expects you to specify a message as a
>>> property that supports expression language and doesn't give you an option
>>> to use the flowfile's content in the message but _does_ allow you to attach
>>> the flowfile.
>>>
>>> If expression language was capable of retrieving flowfile content
>>> directly, I could reduce the number of processors significantly.
>>>
>>> A major problem with this might be the need to introduce a reserved
>>> attribute which would have the potential to cause compatibility problems in
>>> some flows. Or perhaps a function that could serve as the root of an
>>> expression `${content()}`.
>>>
>>> On Mon, Jan 16, 2017 at 11:26 AM, Bryan Bende <[email protected]> wrote:
>>>
>>>> Nick,
>>>>
>>>> The current approach is to use ExtractText to extract the entire flow
>>>> file content to an attribute which can then be referenced in expression
>>>> language.
>>>>
>>>> Keep in mind this means the entire content will be read into memory
>>>> which in some cases may not be a good idea.
>>>>
>>>> I would think that PutSlack should have a strategy to decide where the
>>>> message should come from (attribute vs content), but I am not familiar with
>>>> that processor to really say if it is a good idea.
>>>>
>>>> -Bryan
>>>>
>>>>
>>>> On Mon, Jan 16, 2017 at 1:40 PM, Nick Carenza <
>>>> [email protected]> wrote:
>>>>
>>>>> Is there any way to access flowfile content with expression language?
>>>>>
>>>>> I am trying to use monitor activity with putslack but monitor activity
>>>>> creates flowfiles with confiugrable content but putslack requires you to
>>>>> supply a message property using expression language which as far as i can
>>>>> tell doesn't have access to that flowfile content.
>>>>>
>>>>> Without having to put another processor in between monitor activity
>>>>> and put slack, is there a way to use the flowfile content directly from
>>>>> expression language?
>>>>>
>>>>> If not does anyone else think this would be really useful to make
>>>>> processors like these more compatible?
>>>>>
>>>>
>>>>
>>>
>>
>
>
> --
> *Joe Percivall*
> linkedin.com/in/Percivall
> e: [email protected]
>
