Server Configuration Reference

The Coyote HTTP/1.1 Connector

The Coyote HTTP/1.1 Connector element represents a Connector component that supports the HTTP/1.1 protocol. It enables Catalina to function as a stand-alone web server, in addition to its ability to execute servlets and JSP pages. A particular instance of this component listens for connections on a specific TCP port number on the server. One or more such Connectors can be configured as part of a single Service, each forwarding to the associated Engine to perform request processing and create the response.

If you wish to configure the Connector that is used for connections to web servers using the WARP protocol (such as the mod_webapp connector for Apache 1.3), see here instead.

At server startup time, this Connector will create a number of request processing threads (based on the value configured for the minProcessors attribute). Each incoming request requires a thread for the duration of that request. If more simultaneous requests are received than can be handled by the currently available request processing threads, additional threads will be created up to the configured maximum (the value of the maxProcessors attribute). If still more simultaneous requests are received, they are stacked up inside the server socket created by the Connector, up to the configured maximum (the value of the acceptCount attribute. Any further simultaneous requests will receive "connection refused" errors, until resources are available to process them.

Common Attributes

All implementations of Connector support the following attributes: Attribute Description className Java class name of the implementation to use. This class must implement the org.apache.catalina.Connector interface. You must specify the standard value defined below. enableLookups Set to true if you want calls to request.getRemoteHost() to perform DNS lookups in order to return the actual host name of the remote client. Set to false to skip the DNS lookup and return the IP address in String form instead (thereby improving performance). By default, DNS lookups are disabled. redirectPort If this Connector is supporting non-SSL requests, and a request is received for which a matching <security-constraint> requires SSL transport, Catalina will automatically redirect the request to the port number specified here. scheme Set this attribute to the name of the protocol you wish to have returned by calls to request.getScheme(). For example, you would set this attribute to "https" for an SSL Connector. The default value is "http". See SSL Support for more information. secure Set this attribute to true if you wish to have calls to request.isSecure() to return true for requests received by this Connector (you would want this on an SSL Connector). The default value is false. URIEncoding This specifies the character encoding used to decode the URI bytes, after %xx decoding the URL. If not specified, ISO-8859-1 will be used. useBodyEncodingForURI This specifies if the encoding specified in contentType should be used for URI query parameters, instead of using the URIEncoding. This setting is present for compatibility with Tomcat 4.1.27 and earlier. The default value is true.

Standard Implementation

The standard implementation of the Coyote HTTP/1.1 Connector is org.apache.coyote.tomcat4.CoyoteConnector. It supports the following additional attributes (in addition to the common attributes listed above): Attribute Description acceptCount The maximum queue length for incoming connection requests when all possible request processing threads are in use. Any requests received when the queue is full will be refused. The default value is 10. address For servers with more than one IP address, this attribute specifies which address will be used for listening on the specified port. By default, this port will be used on all IP addresses associated with the server. bufferSize The size (in bytes) of the buffer to be provided for input streams created by this connector. By default, buffers of 2048 bytes will be provided. compression The Connector may use HTTP/1.1 GZIP compression in an attempt to save server bandwidth. The acceptable values for the parameter is "off" (disable compression), "on" (allow compression, which causes text data to be compressed), "force" (forces compression in all cases), or a numerical integer value (which is equivalent to "on", but specifies the minimum amount of data before the output is compressed). If the content-length is not known and compression is set to "on" or more aggressive, the output will also be compressed. If not specified, this attribute is set to "off". connectionLinger The number of milliseconds during which the sockets used by this Connector will linger when they are closed. The default value is -1 (socket linger is disabled). connectionTimeout The number of milliseconds this Connector will wait, after accepting a connection, for the request URI line to be presented. The default value is 60000 (i.e. 60 seconds). debug The debugging detail level of log messages generated by this component, with higher numbers creating more detailed output. If not specified, this attribute is set to zero (0). disableUploadTimeout This flag allows the servlet container to use a different, longer connection timeout while a servlet is being executed, which in the end allows either the servlet a longer amount of time to complete its execution, or a longer timeout during data upload. If not specified, this attribute is set to "false". maxProcessors The maximum number of request processing threads to be created by this Connector, which therefore determines the maximum number of simultaneous requests that can be handled. If not specified, this attribute is set to 20. minProcessors The number of request processing threads that will be created when this Connector is first started. This attribute should be set to a value smaller than that set for maxProcessors. The default value is 5. port The TCP port number on which this Connector will create a server socket and await incoming connections. Your operating system will allow only one server application to listen to a particular port number on a particular IP address. proxyName If this Connector is being used in a proxy configuration, configure this attribute to specify the server name to be returned for calls to request.getServerName(). See Proxy Support for more information. proxyPort If this Connector is being used in a proxy configuration, configure this attribute to specify the server port to be returned for calls to request.getServerPort(). See Proxy Support for more information. tcpNoDelay If set to true, the TCP_NO_DELAY option will be set on the server socket, which improves performance under most circumstances. This is set to true by default.

The only element that may be embedded inside a Connector element is a Factory element, which is used to configure a server socket factory component. See SSL Support for more information about when this is required.

HTTP/1.1 and HTTP/1.0 Support

This Connector supports all of the required features of the HTTP/1.1 protocol, as described in RFC 2616, including persistent connections, pipelining, expectations and chunked encoding. If the client (typically a browser) supports only HTTP/1.0, the Connector will gracefully fall back to supporting this protocol as well. No special configuration is required to enable this support. The Connector also supports HTTP/1.0 keep-alive. RFC 2616 requires that HTTP servers always begin their responses with the highest HTTP version that they claim to support. Therefore, this Connector will always return HTTP/1.1 at the beginning of its responses.

Logging Output

Any debugging or exception logging information generated by this Connector will be automatically routed to the Logger that is associated with our related Engine. No special configuration is required to enable this support.

Proxy Support

The proxyName and proxyPort attributes can be used when Tomcat is run behind a proxy server. These attributes modify the values returned to web applications that call the request.getServerName() and request.getServerPort() methods, which are often used to construct absolute URLs for redirects. Without configuring these attributes, the values returned would reflect the server name and port on which the connection from the proxy server was received, rather than the server name and port to whom the client directed the original request. For more information, see the Proxy Support HOW-TO.

SSL Support

You can enable SSL support for a particular instance of this Connector by nesting an appropriate <Factory> element inside, to set up the required SSL socket factory. This element supports the following attributes: Attribute Description algorithm The certificate encoding algorithm to be used. If not specified, the default value is SunX509. className The fully qualified class name of the SSL server socket factory implementation class. You must specify org.apache.coyote.tomcat4.CoyoteServerSocketFactory here. clientAuth Set to true if you want the SSL stack to require a valid certificate chain from the client before accepting a connection. A false value (which is the default) will not require a certificate chain unless the client requests a resource protected by a security constraint that uses CLIENT-CERT authentication. keystoreFile The pathname of the keystore file where you have stored the server certificate to be loaded. By default, the pathname is the file ".keystore" in the operating system home directory of the user that is running Tomcat. keystorePass The password used to access the server certificate from the specified keystore file. The default value is "changeit". keystoreType The type of keystore file to be used for the server certificate. If not specified, the default value is "JKS". protocol The version of the SSL protocol to use. If not specified, the default is "TLS". For more information, see the SSL Configuration HOW-TO.