Suspect the problem there would be that the ConsumeKafka processors (according to the documentation) don't accept incoming connections, so you've no way of sending the FlowFile from InvokeHttp/HandleHttpRequest to ConsumeKafka to fetch the messages (which you'd possibly then want to MergeContent/MergeRecord to send everything back as a single response).
I'm not very familiar with Kafka processors though, so hopefully someone else can suggest an alternative (or correct me and the NiFi docs if ConsumeKafka isn't just a source processor). --- *Chris Sampson* IT Consultant chris.samp...@naimuri.com <https://www.naimuri.com/> On Thu, 4 Feb 2021 at 14:26, David Handermann <exceptionfact...@gmail.com> wrote: > Ralph, > > Thanks for the reply and additional details. I may be misunderstanding, > but just for clarification, in your diagram, are you expecting NiFi to act > as the REST server? If that is the case, then you should be able to use > one of the ConsumeKafka processors to retrieve messages and return them to > the REST client. At a very basic level, the flow would go from > HandleHttpRequest to ConsumeKafka to HandleHttpResponse. Depending on the > format of the messages retrieved from Kafka, you may need to introduce > additional processors prior to HandleHttpResponse in order to format the > output for delivery to the REST client. > > Regards, > David Handermann > > On Thu, Feb 4, 2021 at 7:47 AM Ralph Vercauteren <r...@qad.com> wrote: > >> Hi David, >> >> Thanks for responding. >> >> I understand that part, still have the issue to see how we get the kafka >> messages from a topic. >> >> [image: image.png] >> >> With regards, >> Mit freundlichem Gruß, >> Met vriendelijke groet, >> >> *Ralph Vercauteren* >> Technical Architect QAD Automation Solutions >> Mobile NL: +31 6 5397 7230 >> r...@qad.com >> >> This e-mail may contain QAD proprietary information and should be treated >> as confidential. >> >> >> On Thu, Feb 4, 2021 at 2:21 PM David Handermann < >> exceptionfact...@gmail.com> wrote: >> >>> Hi Ralph, >>> >>> If you are looking to create a REST service for receiving and processing >>> messages in NiFi, take a look at the ListenHTTP processor, as well as the >>> HandleHttpRequest and HandleHttpResponse processors. The ListenHTTP >>> processor supports receiving HTTP requests and sending the contents to >>> other processors. The ListenHTTP processor provides the easiest approach >>> for getting started. If you need to perform validation or additional >>> processing before sending back a response to REST clients, then using >>> HandleHttpRequest and HandleHttpResponse with other processors in between >>> can support that approach. When using HandleHttpRequest and >>> HandleHttpResponse, it is important to optimize intermediate as much as >>> possible to avoid HTTP clients timing out while waiting for a response. >>> Both processors support a number of configuration properties, so be sure to >>> read through the documentation for each one in order to determine the >>> optimal settings for your configuration. >>> >>> Regards, >>> David Handermann >>> >>> On Thu, Feb 4, 2021 at 3:32 AM Ralph Vercauteren <r...@qad.com> wrote: >>> >>>> Hi all, >>>> >>>> Not sure if I need to ask this in this mailing list or the list of the >>>> developers. >>>> >>>> I want to create a REST server with NIFI. >>>> >>>> I have a Kafka queue storing messages. When something is connected to >>>> the REST server, the Kafka queue has to be read and all waiting messages >>>> should be collected and send back as a response to the REST client, >>>> >>>> I tried to google for a hint or solution, but I couldn't find it. >>>> >>>> With regards, >>>> Mit freundlichem Gruß, >>>> Met vriendelijke groet, >>>> >>>> *Ralph Vercauteren* >>>> Technical Architect QAD Automation Solutions >>>> Mobile NL: +31 6 5397 7230 >>>> r...@qad.com >>>> >>>> This e-mail may contain QAD proprietary information and should be >>>> treated as confidential. >>>> >>>
