Having a problem understanding Body on the server side Im us

Question

Having a problem understanding Body on the server side Im using request body stream to feed to existing java code during a POST usually it works perfectliy but sometimes consistantly I get a EOF on the stream immediately This makes sense if the stream was being read prior but it wasnt by me The comment to StreamBody is scary slightly smiling face but I cant find a comment on how to avoid a SteamBody as far as I can tell debugging the body is already a StreamBody by the time its routed to the handler Still a mystery why it works sometimes and not others regardless if I wanted to avoid the problem how Therese some places in the source where its tested isAvailble and conditionally uses stream or stringBody can I just use stringBody always

dave · Answer

Something is definitely reading your stream It s an age old puzzle But first there s a lot to unpack so let s break it down with some of the usual candidates 1 Are you using a debugging filter which is eating your stream first 2 Are you using the contracts module If so and you ve defined a recieving in your meta block then the preextraction filter will be reading it when verifying the contract To get around this set the preFlightExtraction option in the meta block to only extract the non body parts

dave · Answer

If it is 2 then we have a little bit of a dilemma we can t validate the contract by default without checking the contents Which means reading the stream We could rewrap the read bodyString in the preextractionfilter back into a Memory request and pass it to the endpoint handler which would give the end user access to the stream again but it is a bit of a lie because the contents are really in memory

DALDEI · Answer

re quesions 1 no 2 no I am reading a header however THis is the handler in question a POST handler for AWS SNS messages using the aws SNS servlet handler library object AWSNotifications fun sns req Request Response val messageType=req header x amz sns message type if messageType == null return Response Status BAD REQUEST body Unexpected message missing sns header WTF just use bodyBytes val body = req bodyString val ret=<http SnsHub post|SnsHub post> body byteInputStream Charsets UTF 8 return Response ret body Received fun s3 req Request Response=Response Status OK fun HubServer port Int =HubAPI Hub asServer Jetty port fun server port Int HubServer port start block

DALDEI · Answer

I dont really need this fixed the payload is small and converting to String is find

DALDEI · Answer

Im mainly trying to understand whats going on

DALDEI · Answer

Dont know if it matters but this is a combined websocket and http route

DALDEI · Answer

Im going to guess then that req header Is causing the stream to be read althoguh its a gt 0 arg method so is it writing a header Even so It would be nice if body stream apon detecting that the stream was read created a new one form the body array so code doesnt fall over and die unexpectedly

dave · Answer

Ok first thing I ve added some javadocs to the HttpMessage classes and now this is released as 3 172 0

dave · Answer

I d also like to understand what s going on with your app because it sounds very very strange When you say that ``` usually it works perfectliy but sometimes consistantly I get a EOF on the stream immediately ``` do you mean that for any particular run of the server process it always does it or does the behaviour vary within a single running process instance

dave · Answer

Here s a Gist with what I believe is the same behaviour as your app <https gist github com daviddenton 6c6ca879e96f66779f394ca7a200983b> but this one works ok Would like to see if we can work out where they differ

dave · Answer

I d also be interested to see what the upstream filter stack looks like in `HubAPI Hub `

dave · Answer

ie all the filters composed that are before the request hits the sns handler