Package org.eclipse.jetty.proxy

Class AbstractProxyServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

org.eclipse.jetty.proxy.AbstractProxyServlet

All Implemented Interfaces:

Serializable, javax.servlet.Servlet, javax.servlet.ServletConfig

Direct Known Subclasses:

AsyncMiddleManServlet, ProxyServlet

public abstract class AbstractProxyServlet
extends javax.servlet.http.HttpServlet

Abstract base class for proxy servlets.

Forwards requests to another server either as a standard web reverse proxy or as a transparent reverse proxy (as defined by RFC 7230).

To facilitate JMX monitoring, the HttpClient instance is set as ServletContext attribute, prefixed with this servlet's name and exposed by the mechanism provided by ServletContext.setAttribute(String, Object).

The following init parameters may be used to configure the servlet:

• preserveHost - the host header specified by the client is forwarded to the server
• hostHeader - forces the host header to a particular value
• viaHost - the name to use in the Via header: Via: http/1.1 <viaHost>
• whiteList - comma-separated list of allowed proxy hosts
• blackList - comma-separated list of forbidden proxy hosts

In addition, see createHttpClient() for init parameters used to configure the HttpClient instance.

NOTE: By default the Host header sent to the server by this proxy servlet is the server's host name. However, this breaks redirects. Set preserveHost to true to make redirects working, although this may break server's virtual host selection.

The default behavior of not preserving the Host header mimics the default behavior of Apache httpd and Nginx, which both have a way to be configured to preserve the Host header.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
protected static class	AbstractProxyServlet.TransparentDelegate	Utility class that implement transparent proxy functionalities.

Field Summary

Fields

Modifier and Type	Field	Description
protected org.slf4j.Logger	_log
protected static final String	CLIENT_REQUEST_ATTRIBUTE
protected static final Set<String>	HOP_HEADERS

Constructor Summary

Constructors

Constructor	Description
AbstractProxyServlet()

Method Summary

Modifier and Type	Method	Description
protected void	addProxyHeaders(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest)
protected void	addViaHeader(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest)	Adds the HTTP Via header to the proxied request, taking into account data present in the client request.
protected void	addViaHeader(Request proxyRequest)	Adds the HTTP Via header to the proxied request.
protected void	addXForwardedHeaders(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest)
protected int	clientRequestStatus(Throwable failure)
protected void	copyRequestHeaders(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest)
protected HttpClient	createHttpClient()	Creates a HttpClient instance, configured with init parameters of this servlet.
protected org.slf4j.Logger	createLogger()
void	destroy()
protected boolean	expects100Continue(javax.servlet.http.HttpServletRequest request)
protected String	filterServerResponseHeader(javax.servlet.http.HttpServletRequest clientRequest, Response serverResponse, String headerName, String headerValue)
protected Set<String>	findConnectionHeaders(javax.servlet.http.HttpServletRequest clientRequest)
Set<String>	getBlackListHosts()
String	getHostHeader()
protected HttpClient	getHttpClient()
protected int	getRequestId(javax.servlet.http.HttpServletRequest clientRequest)
long	getTimeout()
String	getViaHost()
Set<String>	getWhiteListHosts()
protected boolean	hasContent(javax.servlet.http.HttpServletRequest clientRequest)
void	init()
protected ClientConnector	newClientConnector()
protected HttpClient	newHttpClient()	The servlet init parameter 'selectors' can be set for the number of selector threads to be used by the HttpClient.
protected HttpClient	newHttpClient(ClientConnector clientConnector)
protected Request	newProxyRequest(javax.servlet.http.HttpServletRequest request, String rewrittenTarget)
protected abstract Response.CompleteListener	newProxyResponseListener(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse)
protected void	onClientRequestFailure(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest, javax.servlet.http.HttpServletResponse proxyResponse, Throwable failure)
protected void	onContinue(javax.servlet.http.HttpServletRequest clientRequest, Request proxyRequest)
protected void	onProxyResponseFailure(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse, Response serverResponse, Throwable failure)
protected void	onProxyResponseSuccess(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse, Response serverResponse)
protected void	onProxyRewriteFailed(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse)	Callback method invoked when the URI rewrite performed in rewriteTarget(HttpServletRequest) returns null indicating that no rewrite can be performed.
protected void	onServerResponseHeaders(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse, Response serverResponse)
protected int	proxyResponseStatus(Throwable failure)
protected String	rewriteTarget(javax.servlet.http.HttpServletRequest clientRequest)
protected void	sendProxyRequest(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse, Request proxyRequest)
protected void	sendProxyResponseError(javax.servlet.http.HttpServletRequest clientRequest, javax.servlet.http.HttpServletResponse proxyResponse, int status)
void	setTimeout(long timeout)
boolean	validateDestination(String host, int port)	Checks the given host and port against whitelist and blacklist.

Methods inherited from class javax.servlet.http.HttpServlet

doDelete, doGet, doHead, doOptions, doPost, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, init, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

CLIENT_REQUEST_ATTRIBUTE

protected static final String CLIENT_REQUEST_ATTRIBUTE

See Also:

• Constant Field Values

HOP_HEADERS

protected static final Set<String> HOP_HEADERS

_log

protected org.slf4j.Logger _log

Constructor Details

AbstractProxyServlet

public AbstractProxyServlet()

Method Details

init

public void init()
          throws javax.servlet.ServletException

Overrides:

init in class javax.servlet.GenericServlet

Throws:

javax.servlet.ServletException

destroy

public void destroy()

Specified by:

destroy in interface javax.servlet.Servlet

Overrides:

destroy in class javax.servlet.GenericServlet

getHostHeader

public String getHostHeader()

getViaHost

public String getViaHost()

getTimeout

public long getTimeout()

setTimeout

public void setTimeout(long timeout)

getWhiteListHosts

public Set<String> getWhiteListHosts()

getBlackListHosts

public Set<String> getBlackListHosts()

createLogger

protected org.slf4j.Logger createLogger()

Returns:

a logger instance with a name derived from this servlet's name.

createHttpClient

protected HttpClient createHttpClient()
                               throws javax.servlet.ServletException

Creates a HttpClient instance, configured with init parameters of this servlet.

The init parameters used to configure the HttpClient instance are:

Init Parameters

init-param	default	description
maxThreads	256	The max number of threads of HttpClient's Executor. If not set, or set to the value of "-", then the Jetty server thread pool will be used.
maxConnections	32768	The max number of connections per destination, see HttpClient.setMaxConnectionsPerDestination(int)
idleTimeout	30000	The idle timeout in milliseconds, see HttpClient.setIdleTimeout(long)
timeout	60000	The total timeout in milliseconds, see Request.timeout(long, java.util.concurrent.TimeUnit)
requestBufferSize	HttpClient's default	The request buffer size, see HttpClient.setRequestBufferSize(int)
responseBufferSize	HttpClient's default	The response buffer size, see HttpClient.setResponseBufferSize(int)
selectors	cores / 2	The number of NIO selectors used by HttpClient

Returns:

a HttpClient configured from the servlet configuration

Throws:

javax.servlet.ServletException - if the HttpClient cannot be created

See Also:

• newHttpClient()

newHttpClient

protected HttpClient newHttpClient()

The servlet init parameter 'selectors' can be set for the number of selector threads to be used by the HttpClient.

Returns:

a new HttpClient instance

newHttpClient

protected HttpClient newHttpClient(ClientConnector clientConnector)

newClientConnector

protected ClientConnector newClientConnector()

getHttpClient

protected HttpClient getHttpClient()

validateDestination

public boolean validateDestination(String host,
 int port)

Checks the given host and port against whitelist and blacklist.

Parameters:

host - the host to check

port - the port to check

Returns:

true if it is allowed to be proxy to the given host and port

rewriteTarget

protected String rewriteTarget(javax.servlet.http.HttpServletRequest clientRequest)

onProxyRewriteFailed

protected void onProxyRewriteFailed(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse)

Callback method invoked when the URI rewrite performed in rewriteTarget(HttpServletRequest) returns null indicating that no rewrite can be performed.

It is possible to use blocking API in this method, like HttpServletResponse.sendError(int).

Parameters:

clientRequest - the client request

proxyResponse - the client response

hasContent

protected boolean hasContent(javax.servlet.http.HttpServletRequest clientRequest)

expects100Continue

protected boolean expects100Continue(javax.servlet.http.HttpServletRequest request)

newProxyRequest

protected Request newProxyRequest(javax.servlet.http.HttpServletRequest request,
 String rewrittenTarget)

copyRequestHeaders

protected void copyRequestHeaders(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest)

findConnectionHeaders

protected Set<String> findConnectionHeaders(javax.servlet.http.HttpServletRequest clientRequest)

addProxyHeaders

protected void addProxyHeaders(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest)

addViaHeader

protected void addViaHeader(Request proxyRequest)

Adds the HTTP Via header to the proxied request.

Parameters:

proxyRequest - the request being proxied

See Also:

• addViaHeader(HttpServletRequest, Request)

addViaHeader

protected void addViaHeader(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest)

Adds the HTTP Via header to the proxied request, taking into account data present in the client request.

This method considers the protocol of the client request when forming the proxied request. If it is HTTP, then the protocol name will not be included in the Via header that is sent by the proxy, and only the protocol version will be sent. If it is not, the entire protocol (name and version) will be included. If the client request includes a Via header, the result will be appended to that to form a chain.

Parameters:

clientRequest - the client request

proxyRequest - the request being proxied

See Also:

• RFC 7230 section 5.7.1

addXForwardedHeaders

protected void addXForwardedHeaders(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest)

sendProxyRequest

protected void sendProxyRequest(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 Request proxyRequest)

newProxyResponseListener

protected abstract Response.CompleteListener newProxyResponseListener(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse)

onClientRequestFailure

protected void onClientRequestFailure(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 Throwable failure)

clientRequestStatus

protected int clientRequestStatus(Throwable failure)

onServerResponseHeaders

protected void onServerResponseHeaders(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 Response serverResponse)

filterServerResponseHeader

protected String filterServerResponseHeader(javax.servlet.http.HttpServletRequest clientRequest,
 Response serverResponse,
 String headerName,
 String headerValue)

onProxyResponseSuccess

protected void onProxyResponseSuccess(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 Response serverResponse)

onProxyResponseFailure

protected void onProxyResponseFailure(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 Response serverResponse,
 Throwable failure)

proxyResponseStatus

protected int proxyResponseStatus(Throwable failure)

getRequestId

protected int getRequestId(javax.servlet.http.HttpServletRequest clientRequest)

sendProxyResponseError

protected void sendProxyResponseError(javax.servlet.http.HttpServletRequest clientRequest,
 javax.servlet.http.HttpServletResponse proxyResponse,
 int status)

onContinue

protected void onContinue(javax.servlet.http.HttpServletRequest clientRequest,
 Request proxyRequest)