From 60f1fd4185ca1cfdb977e8470a7365b20b013e9c Mon Sep 17 00:00:00 2001 From: ooeunz Date: Sun, 1 Nov 2026 16:45:57 +0900 Subject: [PATCH] Add option to keep connections open after error status codes The HTTP/1.1 connector closes the connection after a response with a status code of 400, 408, 411, 413, 414, 500, 501 or 503. Clients then have to re-establish the connection, which increases HTTP resource usage when these responses are frequent. Add the dropConnectionOnErrorStatus connector attribute so this behaviour can be disabled. The default of true retains the current behaviour. Connections are still closed when it is not safe to re-use them. --- .../coyote/http11/AbstractHttp11Protocol.java | 24 +++ .../apache/coyote/http11/Http11Processor.java | 4 +- .../coyote/http11/TestHttp11Processor.java | 173 ++++++++++++++++++ webapps/docs/changelog.xml | 7 + webapps/docs/config/http.xml | 11 ++ 5 files changed, 218 insertions(+), 1 deletion(-) diff --git a/java/org/apache/coyote/http11/AbstractHttp11Protocol.java b/java/org/apache/coyote/http11/AbstractHttp11Protocol.java index b7ec72c203d0..78747aa29620 100644 --- a/java/org/apache/coyote/http11/AbstractHttp11Protocol.java +++ b/java/org/apache/coyote/http11/AbstractHttp11Protocol.java @@ -212,6 +212,30 @@ public void setUseKeepAliveResponseHeader(boolean useKeepAliveResponseHeader) { } + private boolean dropConnectionOnErrorStatus = true; + + /** + * Get the flag that controls whether the connection is closed after a response with a status code from the list of + * codes that Tomcat treats as requiring the connection to be closed. Errors that make it unsafe to continue to use + * the connection, such as requests that can not be parsed, always close the connection regardless of this setting. + * + * @return {@code true} if the connection will be closed after such a response + */ + public boolean getDropConnectionOnErrorStatus() { + return dropConnectionOnErrorStatus; + } + + /** + * Set the flag that controls whether the connection is closed after a response with a status code from the list of + * codes that Tomcat treats as requiring the connection to be closed. + * + * @param dropConnectionOnErrorStatus {@code true} if the connection should be closed after such a response + */ + public void setDropConnectionOnErrorStatus(boolean dropConnectionOnErrorStatus) { + this.dropConnectionOnErrorStatus = dropConnectionOnErrorStatus; + } + + private String relaxedPathChars = null; /** diff --git a/java/org/apache/coyote/http11/Http11Processor.java b/java/org/apache/coyote/http11/Http11Processor.java index a8bee04f9408..897614f8b37e 100644 --- a/java/org/apache/coyote/http11/Http11Processor.java +++ b/java/org/apache/coyote/http11/Http11Processor.java @@ -408,6 +408,7 @@ public SocketState service(SocketWrapperBase socketWrapper) throws IOExceptio // If we fail here, then the response is likely already // committed, so we can't try and set headers. if (keepAlive && !getErrorState().isError() && !isAsync() && + protocol.getDropConnectionOnErrorStatus() && statusDropsConnection(response.getStatus())) { setErrorState(ErrorState.CLOSE_CLEAN, null); } @@ -1028,7 +1029,8 @@ protected final void prepareResponse() throws IOException { // If we know that the request is bad this early, add the // Connection: close header. - if (keepAlive && statusDropsConnection(statusCode)) { + if (keepAlive && statusDropsConnection(statusCode) && + (protocol.getDropConnectionOnErrorStatus() || getErrorState().isError())) { keepAlive = false; } if (!keepAlive) { diff --git a/test/org/apache/coyote/http11/TestHttp11Processor.java b/test/org/apache/coyote/http11/TestHttp11Processor.java index 6ed4bbb8385d..643622775170 100644 --- a/test/org/apache/coyote/http11/TestHttp11Processor.java +++ b/test/org/apache/coyote/http11/TestHttp11Processor.java @@ -29,6 +29,7 @@ import java.net.InetSocketAddress; import java.net.Socket; import java.net.SocketAddress; +import java.net.SocketException; import java.nio.CharBuffer; import java.nio.charset.StandardCharsets; import java.util.ArrayList; @@ -1787,6 +1788,178 @@ private void doTestKeepAliveHeader(boolean sendKeepAlive, int keepAliveTimeout, } + @Test + public void testDropConnectionOnErrorStatusDefault() throws Exception { + Client client = startDropConnectionTest(null, null); + client.setRequest(new String[] { dropConnectionRequest("GET", "/error", "") }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse50x()); + assertConnectionClosedAfterResponse(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabled() throws Exception { + Client client = startDropConnectionTest("false", null); + client.setRequest(new String[] { dropConnectionRequest("GET", "/error", "") }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse50x()); + Assert.assertNull(getConnectionHeader(client)); + assertConnectionReusable(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabledInvalidRequestLine() throws Exception { + Client client = startDropConnectionTest("false", null); + client.setRequest(new String[] { "GET /foo\u0001 HTTP/1.1" + CRLF + "Host: localhost" + CRLF + CRLF }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse400()); + assertConnectionClosedAfterResponse(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabledMissingHost() throws Exception { + Client client = startDropConnectionTest("false", null); + client.setRequest(new String[] { "GET /foo HTTP/1.1" + CRLF + CRLF }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse400()); + assertConnectionClosedAfterResponse(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabledUnsupportedEncoding() throws Exception { + Client client = startDropConnectionTest("false", null); + // @formatter:off + String request = + "POST /foo HTTP/1.1" + CRLF + + "Host: localhost" + CRLF + + "Transfer-Encoding: unsupported" + CRLF + + CRLF; + // @formatter:on + client.setRequest(new String[] { request }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse50x()); + Assert.assertTrue(client.getResponseLine(), client.getResponseLine().contains(" 501")); + assertConnectionClosedAfterResponse(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabledSwallowBody() throws Exception { + Client client = startDropConnectionTest("false", null); + client.setRequest(new String[] { dropConnectionRequest("POST", "/error", "0123456789") }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse50x()); + Assert.assertNull(getConnectionHeader(client)); + // The next request will fail to parse if the unread body was not swallowed + assertConnectionReusable(client); + } + + + @Test + public void testDropConnectionOnErrorStatusDisabledBodyExceedsMaxSwallowSize() throws Exception { + Client client = startDropConnectionTest("false", "10"); + client.setRequest(new String[] { dropConnectionRequest("POST", "/error", "0123456789ABCDEF") }); + client.processRequest(true); + + Assert.assertTrue(client.isResponse50x()); + assertConnectionClosedAfterResponse(client); + } + + + private Client startDropConnectionTest(String dropConnectionOnErrorStatus, String maxSwallowSize) + throws Exception { + Tomcat tomcat = getTomcatInstance(); + + if (dropConnectionOnErrorStatus != null) { + Assert.assertTrue( + tomcat.getConnector().setProperty("dropConnectionOnErrorStatus", dropConnectionOnErrorStatus)); + } + if (maxSwallowSize != null) { + Assert.assertTrue(tomcat.getConnector().setProperty("maxSwallowSize", maxSwallowSize)); + } + + // No file system docBase required + Context ctx = getProgrammaticRootContext(); + + Tomcat.addServlet(ctx, "ErrorStatusServlet", new ErrorStatusServlet()); + ctx.addServletMapping("/*", "ErrorStatusServlet"); + + tomcat.start(); + + Client client = new Client(tomcat.getConnector().getLocalPort()); + client.setUseContentLength(true); + client.connect(); + return client; + } + + + private static String dropConnectionRequest(String method, String path, String body) { + // @formatter:off + return method + " " + path + " HTTP/1.1" + CRLF + + "Host: localhost" + CRLF + + (body.isEmpty() ? "" : "Content-Length: " + body.length() + CRLF) + + CRLF + + body; + // @formatter:on + } + + + private static String getConnectionHeader(Client client) { + for (String header : client.getResponseHeaders()) { + if (header.regionMatches(true, 0, "Connection:", 0, 11)) { + return header.substring(11).trim(); + } + } + return null; + } + + + private static void assertConnectionClosedAfterResponse(Client client) throws IOException { + Assert.assertEquals("close", getConnectionHeader(client)); + try { + Assert.assertNull(client.readLine()); + } catch (SocketException e) { + // A TCP reset also shows that the server closed the connection + } + } + + + private static void assertConnectionReusable(Client client) throws Exception { + client.setRequest(new String[] { dropConnectionRequest("GET", "/ok", "") }); + client.processRequest(true); + + Assert.assertTrue(client.getResponseLine(), client.isResponse200()); + Assert.assertEquals("OK", client.getResponseBody()); + } + + + private static final class ErrorStatusServlet extends HttpServlet { + + private static final long serialVersionUID = 1L; + + @Override + protected void service(HttpServletRequest req, HttpServletResponse resp) throws IOException { + if (req.getRequestURI().equals("/error")) { + resp.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR); + } else { + resp.setContentType("text/plain"); + resp.setContentLength(2); + resp.getWriter().print("OK"); + } + } + } + + /** * Test servlet that prints out the values of HttpServletRequest.getServerName() and * HttpServletRequest.getServerPort() in the response body, e.g.: "request.getServerName() is [foo] and diff --git a/webapps/docs/changelog.xml b/webapps/docs/changelog.xml index fc1d308edd95..f5c89f4abef9 100644 --- a/webapps/docs/changelog.xml +++ b/webapps/docs/changelog.xml @@ -664,6 +664,13 @@ Detect and disconnect a mis-behaving HTTP/2 client that sends large numbers of unexpected settings acknowledgement frames. (markt) + + Add the dropConnectionOnErrorStatus attribute to the HTTP/1.1 + connector to allow the closing of the connection after a response with + selected 4xx and 5xx status codes to be disabled, reducing the resources + used to re-establish those connections. The default value of + true retains the current behaviour. (ooeunz) + diff --git a/webapps/docs/config/http.xml b/webapps/docs/config/http.xml index c87099b58772..40f178baa4fd 100644 --- a/webapps/docs/config/http.xml +++ b/webapps/docs/config/http.xml @@ -557,6 +557,17 @@

+ +

(bool) Use this attribute to control whether the connection is closed + after a response with a status code of 400, 408, 411, 413, 414, 500, 501 + or 503. If set to false, the connection may be re-used for + further requests after such a response. The connection will still be + closed if it is not safe to re-use it, for example if the request could + not be parsed, if the request used an unsupported transfer encoding or if + the unread part of the request body exceeds maxSwallowSize. + If not specified, this attribute is set to true.

+ +

A reference to the name in an Executor element. If this attribute is set, and the named executor exists, the