POST will hang at execute

[kensee]

Hi,

I created a simple form to do a POST and it hang at proxyResponse = proxyClient.execute. GET is working fine.

Anyone having the same issue? or am I missing something.

[IgnasD]

Hello,

Same here. Have no idea what's wrong. It's a shame since it is the only HTTP reverse proxy servlet I could find.

[dsmiley]

Please debug it. Perhaps an older version of this proxy didn't have this problem? Maybe it's sensitive to which HttpClient is used?

[kensee]

Seems like the way it handle POST is broken. Had to change it to handle multipart and standard POST.

[IgnasD]

Sorry for the delayed response.

@kensee, if I understood you correctly, it seems that you have already done all the debugging. If so, could you share the solution?

[IgnasD]

@dsmiley, so I did some debugging and in my case it is dup of #54.

OrderedHiddenHttpMethodFilter of Spring Boot is calling getParameter and body of the request gets consumed. So when proxy calls getInputStream, it gets blank input.

InputStreamEntity is created with explicitly specified content length, which is non-zero, so InputStreamEntity tries to read specified byte count indefinitely thus creating the hang effect.

[dsmiley]

Aaaah; yes. This is not a bug but a.... "gotcha", if you will, with knowing how not to use this servlet. If you can suggest a work-around for Spring Boot in particular, or can surmise how the proxy itself might better handle this, I welcome your input.

[IgnasD]

Well, in my case, disabling WebMvcAutoConfiguration was acceptable solution:
@SpringBootApplication(exclude = { WebMvcAutoConfiguration.class })

About handling this situation better in proxy side, I have no ideas that I like.

[kuun]

The proxy can't handle 100 continue, if the post contains header 'Expect: 100 continue', it can't forward request body to server.

[dsmiley]

@kuun do you believe your comment applies to the O.P.'s issue? If you're not sure then please file a new issue. I ought to close this one, I think.

[luxmentis]

My solution to the Spring Boot problem was to refactor the proxy code so it could be called from a filter. You also need to make sure the filter executes before Spring's ones: use a FilterRegistrationBean and set order = Integer.MIN_VALUE.
Although I guess it's nice to have all the code in one file, it'd be more flexible to provide a filter as well as a servlet. Most of the code would be shared. (I wonder if I've missed any gotchas. We'll see.)

[dsmiley]

@Seldomseenkid Although I want the core servlet to be stand-alone (one source file), I'm open to the idea of adding a separate HttpProxyServletFilter class that has a reference to ProxyServlet (or URITemplateProxyServlet) to do the vast majority of the work. I'm not sure of the details to know if this makes sense or not.

[chambjl]

I was able to resolve this issue in my project by disabling HiddenHttpMethodFilter, as follows:

    @Bean
    public FilterRegistrationBean registration(HiddenHttpMethodFilter filter) {
        FilterRegistrationBean registration = new FilterRegistrationBean(filter);
        registration.setEnabled(false);
        return registration;
    }

That particular solution was found here: https://stackoverflow.com/questions/8522568/why-is-httpservletrequest-inputstream-empty

Spring Boot version: 1.4.1.RELEASE

[eis]

Yes! Disabling HiddenHttpMethodFilter worked for me too.

[Nisus-Liu]

I looked HiddenHttpMethodFilter, but I did not see what 'bad things' it did??
Follow code is part of HiddenHttpMethodFilter.

	@Override
	protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
			throws ServletException, IOException {

		HttpServletRequest requestToUse = request;

		if ("POST".equals(request.getMethod()) && request.getAttribute(WebUtils.ERROR_EXCEPTION_ATTRIBUTE) == null) {
			String paramValue = request.getParameter(this.methodParam);
			if (StringUtils.hasLength(paramValue)) {
				requestToUse = new HttpMethodRequestWrapper(request, paramValue);
			}
		}

		filterChain.doFilter(requestToUse, response);
	}

[dsmiley]

It calls request.getParameter which looks super innocent but it has a side-effect of consuming the POST'ed input stream. See it's javadocs.