Added a MiddlewareBuilder for easily chaining HttpHandlers

[billoneil]

This is something I added on a side project of mine and thought it might be useful. If there is already a way to do this or you have any suggestions please let me know. If you feel it doesn't belong thats also fine.

Here is a more real world example of how I use it on my side project.

private static final HttpHandler wrapWithMiddleware(HttpHandler handler) {
    return MiddlewareBuilder.begin(BlockingHandler::new)
                            .next(CustomHandlers::requestLogging)
                            .next(CustomHandlers::statusCodeMetrics)
                            .next(Server::exceptionHandler)
                            .complete(handler);
}

[undertow-pull-request]

Can one of the admins verify this patch?

[ctomc]

this is ok to test

[undertow-pull-request]

Windows Build 1675 outcome was FAILURE using a merge of 412669c
Summary: Tests failed: 1, passed: 2179, ignored: 713 Build time: 00:20:07

Failed tests

io.undertow.server.handlers.proxy.LoadBalancingProxyHttpsTestCase.testDuplicateHeaders: java.lang.AssertionError: Test failed with i=3 expected:<200> but was:<500>
------- Stderr: -------
13:11:34,308 DEBUG (XNIO-1 I/O-1) [io.undertow.server.handlers.proxy] <ProxyHandler.java:497> Sending request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Host=[localhost:7777]} response {}}
13:11:34,310 DEBUG (XNIO-1 I/O-1) [io.undertow.server.handlers.proxy] <ProxyHandler.java:504> Sent request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Host=[localhost:7777]} response {}}
13:11:34,315 DEBUG (XNIO-1 I/O-1) [io.undertow.server.handlers.proxy] <ProxyHandler.java:614> Received response io.undertow.client.ClientResponse@ef0e5e for request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Host=[localhost:7777]} response {}}
13:11:34,320 DEBUG (XNIO-1 I/O-3) [io.undertow.server.handlers.proxy] <ProxyHandler.java:497> Sending request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,322 DEBUG (XNIO-1 I/O-3) [io.undertow.server.handlers.proxy] <ProxyHandler.java:504> Sent request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,327 DEBUG (XNIO-1 I/O-3) [io.undertow.server.handlers.proxy] <ProxyHandler.java:614> Received response io.undertow.client.ClientResponse@11c78e3 for request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,334 DEBUG (XNIO-1 I/O-5) [io.undertow.server.handlers.proxy] <ProxyHandler.java:497> Sending request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,336 DEBUG (XNIO-1 I/O-5) [io.undertow.server.handlers.proxy] <ProxyHandler.java:504> Sent request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,341 DEBUG (XNIO-1 I/O-5) [io.undertow.server.handlers.proxy] <ProxyHandler.java:614> Received response io.undertow.client.ClientResponse@17f0d28 for request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,344 DEBUG (XNIO-1 I/O-7) [io.undertow.server.handlers.proxy] <ProxyHandler.java:497> Sending request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,347 DEBUG (XNIO-1 I/O-7) [io.undertow.server.handlers.proxy] <ProxyHandler.java:504> Sent request ClientRequest{path='/session', method=GET, protocol=HTTP/1.1} to target 127.0.0.1 for exchange HttpServerExchange{ GET /session request {Connection=[close], a=[b, b, b, b, b, b, b, b], Cookie=[JSESSIONID=LFUTOryCQlQo1mp8YK-zs9H_9-YcV5Ex9jAfSB4W.s1], User-Agent=[Apache-HttpClient/4.2.6 (java 1.5)], Cookie2=[$Version=1], Host=[localhost:7777]} response {}}
13:11:34,349 DEBUG (XNIO-1 I/O-7) [io.undertow.request.io] <SslConduit.java:608> UT005013: An IOException occurred: java.io.IOException: javax.net.ssl.SSLException: Inbound closed before receiving peer's close_notify: possible truncation attack?
    at io.undertow.protocols.ssl.SslConduit.notifyReadClosed(SslConduit.java:608)
    at io.undertow.protocols.ssl.SslConduit.closed(SslConduit.java:973)
    at io.undertow.protocols.ssl.SslConduit.close(SslConduit.java:1068)
    at io.undertow.protocols.ssl.SslConduit.doUnwrap(SslConduit.java:789)
    at io.undertow.protocols.ssl.SslConduit.doWrap(SslConduit.java:839)
    at io.undertow.protocols.ssl.SslConduit.write(SslConduit.java:371)
    at io.undertow.client.http.HttpRequestConduit.processWrite(HttpRequestConduit.java:113)
    at io.undertow.client.http.HttpRequestConduit.flush(HttpRequestConduit.java:573)
    at io.undertow.conduits.AbstractFixedLengthStreamSinkConduit.flush(AbstractFixedLengthStreamSinkConduit.java:229)
    at org.xnio.conduits.ConduitStreamSinkChannel.flush(ConduitStreamSinkChannel.java:162)
    at org.xnio.ChannelListeners$14.handleEvent(ChannelListeners.java:413)
    at org.xnio.ChannelListeners$14.handleEvent(ChannelListeners.java:409)
    at org.xnio.ChannelListeners.invokeChannelListener(ChannelListeners.java:92)
    at org.xnio.conduits.WriteReadyHandler$ChannelListenerHandler.writeReady(WriteReadyHandler.java:65)
    at io.undertow.protocols.ssl.SslConduit$SslWriteReadyHandler.writeReady(SslConduit.java:1214)
    at io.undertow.protocols.ssl.SslConduit$4.run(SslConduit.java:430)
    at org.xnio.nio.WorkerThread.safeRun(WorkerThread.java:580)
    at org.xnio.nio.WorkerThread.run(WorkerThread.java:464)
Caused by: javax.net.ssl.SSLException: Inbound closed before receiving peer's close_notify: possible truncation attack?
    at sun.security.ssl.Alerts.getSSLException(Alerts.java:208)
    at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1666)
    at sun.security.ssl.SSLEngineImpl.fatal(SSLEngineImpl.java:1634)
    at sun.security.ssl.SSLEngineImpl.closeInbound(SSLEngineImpl.java:1561)
    at io.undertow.protocols.ssl.SslConduit.notifyReadClosed(SslConduit.java:606)
    ... 17 more

13:11:34,360 ERROR (XNIO-1 I/O-7) [io.undertow.proxy] <ProxyHandler.java:650> UT005028: Proxy request to /session failed: java.io.IOException: An established connection was aborted by the software in your host machine
    at sun.nio.ch.SocketDispatcher.read0(Native Method)
    at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:43)
    at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
    at sun.nio.ch.IOUtil.read(IOUtil.java:192)
    at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:380)
    at org.xnio.nio.NioSocketConduit.read(NioSocketConduit.java:286)
    at io.undertow.protocols.ssl.SslConduit.doUnwrap(SslConduit.java:694)
    at io.undertow.protocols.ssl.SslConduit.doWrap(SslConduit.java:839)
    at io.undertow.protocols.ssl.SslConduit.write(SslConduit.java:371)
    at io.undertow.client.http.HttpRequestConduit.processWrite(HttpRequestConduit.java:113)

[stuartwdouglas]

Sorry for the delay in replying. To be honest I am not sure if we need this in Undertow core. We already have HandlerWrapper which kind of does the same job. I think your syntax is a bit nicer but I don't know if that justifies making it a supported part of Undertow

[billoneil]

Ah I didn't see those before. No problem.