Request forwarding is not working with ServletHttpHandlerAdapter in servlet 3.1 container [SPR-17637]

[spring-projects-issues]

codecracker2014 opened SPR-17637 and commented

I'm trying to write reactive view resolver for apache tiles. Tiles forwards request to jsp and jsp calls 

getOutputStream which can't be called twice as already called in org.springframework.http.server.reactive.ServletServerHttpResponse constructor.
Below is the resulting exception.

java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:624)

Is request forwarding not supported with web-flux?

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No further details from SPR-17637

[spring-projects-issues]

codecracker2014 commented

Rossen Stoyanchev i'm able to properly render view with overriding getWriter method of http response

as below :

DataBuffer dataBuffer = this.httpResponse.bufferFactory().allocateBuffer();
DataBuffer dataBuffer = this.httpResponse.bufferFactory().allocateBuffer(); this.dataBuffer=dataBuffer; this.printWriter=new ReactivePrintWriter(dataBuffer.asOutputStream());

 Then returning below from renderInternal method of AbstractUrlBasedView

 

return exchange.getResponse().writeWith(Flux.just(dataBuffer));

Need your help to review this approach.

 

[spring-projects-issues]

Brian Clozel commented

codecracker2014 I've answered your question on StackOverflow - please avoid cross-posting.

As mentioned in that answer, this might be a duplicate of #19106. But taking a step back, I don't think it is possible to implement the support for a templating engine that's tied to the Servlet API. So this might be a non-starter.

[spring-projects-issues]

Rossen Stoyanchev commented

As Brian Clozel mentioned on StackOverflow, WebFlux supports Servlet containers but not the Servlet API, and by extension that means no support for JSPs.