Cannot save after editing big sized diagram

[asimionxwiki]

Describe the bug
When trying to edit a big diagram, I cannot save due to a " Server Not Responding" Error. This applies to the attached XAR file.

Expected behavior
The diagram should be saved after editing it.

Actual behavior
Server Not Responding Error is being thrown when I try to save and view.

Screenshots

Environment (please complete the following information):

• OS: [iOS]
• Browser [Firefox]
• XWiki version [17.4.7]
• App version [e.g. 1.23]

Diagramtest.zip

[petrenkonikita112263]

I managed to reproduce it locally on both 15.10 and 17.4.7 demo Jetty/HSQLDB with latest Diagram Pro (included trial license).

First, you need to create a simple blank diagram and re-edit it in wiki mode, replacing the content with an XML representation from a shared archive. For this, you have to copy the content between <content>....</content> tags of file Diagramtest/testsida/Diagram.xml.

Try saving it after. Note that you may experience some slowness for about 1 minute without response, after which XWiki will return an "Bad Request" error in the browser with a stack trace in the Network tab.

Caused by:
org.eclipse.jetty.http.BadMessageException: 400: Unable to parse form content
	at org.eclipse.jetty.server.Request.getParameters(Request.java:471)
	at org.eclipse.jetty.server.Request.getParameterMap(Request.java:1058)
	at javax.servlet.ServletRequestWrapper.getParameterMap(ServletRequestWrapper.java:158)
	at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter$SavedRequestWrapper.getParameterMap(SavedRequestRestorerFilter.java:164)
	at org.xwiki.wysiwyg.internal.filter.http.MutableHttpServletRequest.<init>(MutableHttpServletRequest.java:58)
	at org.xwiki.wysiwyg.internal.filter.http.MutableHttpServletRequestFactory.newInstance(MutableHttpServletRequestFactory.java:43)
	at org.xwiki.wysiwyg.internal.converter.DefaultRequestParameterConverter.convert(DefaultRequestParameterConverter.java:104)
	at org.xwiki.wysiwyg.internal.converter.DefaultRequestParameterConverter.convert(DefaultRequestParameterConverter.java:90)
	at org.xwiki.wysiwyg.filter.ConversionFilter.doFilter(ConversionFilter.java:58)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.xwiki.container.servlet.filters.internal.SetHTTPHeaderFilter.doFilter(SetHTTPHeaderFilter.java:63)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.xwiki.resource.servlet.RoutingFilter.doFilter(RoutingFilter.java:132)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.xwiki.container.servlet.filters.internal.SavedRequestRestorerFilter.doFilter(SavedRequestRestorerFilter.java:208)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.xwiki.container.servlet.filters.internal.SetCharacterEncodingFilter.doFilter(SetCharacterEncodingFilter.java:111)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:210)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.eclipse.jetty.websocket.servlet.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:170)
	at org.eclipse.jetty.servlet.FilterHolder.doFilter(FilterHolder.java:202)
	at org.eclipse.jetty.servlet.ServletHandler$Chain.doFilter(ServletHandler.java:1635)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:527)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:131)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:598)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:122)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:223)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1570)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:221)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1384)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:176)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:484)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1543)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:174)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1306)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:129)
	at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:192)
	at org.eclipse.jetty.server.handler.HandlerList.handle(HandlerList.java:51)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:122)
	at org.eclipse.jetty.server.Server.handle(Server.java:563)
	at org.eclipse.jetty.server.HttpChannel$RequestDispatchable.dispatch(HttpChannel.java:1598)
	at org.eclipse.jetty.server.HttpChannel.dispatch(HttpChannel.java:753)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:501)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:287)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:314)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:100)
	at org.eclipse.jetty.io.SelectableChannelEndPoint$1.run(SelectableChannelEndPoint.java:53)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:969)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.doRunJob(QueuedThreadPool.java:1194)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:1149)
	at java.base/java.lang.Thread.run(Thread.java:840)
Caused by: java.lang.IllegalStateException: Form is larger than max length 1000000
	at org.eclipse.jetty.server.Request.extractFormParameters(Request.java:593)
	at org.eclipse.jetty.server.Request.extractContentParameters(Request.java:546)
	at org.eclipse.jetty.server.Request.getParameters(Request.java:466)
	... 54 more

There's FAQ entry regarding such error. And I can confirm, once I have increased maxFormContentSize (i.e <Set name="maxFormContentSize">5000000</Set>) and restarted the Jetty servlet, XWiki manages to save such diagram.

Here's the picture of diagram