sunlabs.brazil.handler
Class GenericProxyHandler

java.lang.Object
  sunlabs.brazil.handler.GenericProxyHandler (view source)

All Implemented Interfaces:

Handler

Direct Known Subclasses:

MultiProxyHandler, ProxyPropertiesHandler

public class GenericProxyHandler
extends Object
implements Handler

Handler for implementing a virtual web site. This causes another web site to "appear" inside our document root. This classes is intended to be sub-classed, so some of the methods in this implementation don't do too much. All of the appropriate links in HTML documents on the virtual site are rewritten, so they appear to be local references. This can be used on a firewall in conjunction with AclSwitchHandler to provide authenticated access to selected web sites.

Properties:

prefix

URL prefix must match

host

name of host site to proxy to.

protocol

defaultPort

Hormally all requests are fetched via "http", using the default port of 80. The "protocol" and "defaultPort" settings may be used to get other protocols. For example:

  protocol=https
  defaultPort=443
 

port

Host port to proxy to (defaults to defaultPort).

proxyHost

Which proxy host to use (if any) to contact "host".

proxyPort

The proxy's port (defaults to defaultPort)

headers

A list of white space delimited tokens that refer to additional HTTP headers that are added onto the polled request. For each token the server properties [token].name and [token].value define a new http header.

passHost

If true, the original browser host string is passed to the target, otherwise the mapped hostname is used, in which case the http header "X-Host-Orig" will contain the original host name.

noErrorReturn

If true, then if the proxy request fails, the response method returns "false", and places the reason for failure in the "errorCode" and "errorMsg" request properties. Otherwise, and error response is generated. The default is (erroneously) false for historical reasons.

Nested Class Summary

static class

GenericProxyHandler.Cookie

Field Summary

static String	HOST Handler configuration property host.
static String	NL
static String	PORT Handler configuration property port.
static String	PREFIX Handler configuration property prefix.
static String	PROXY_HOST Handler configuration property proxyHost.
static String	PROXY_PORT Handler configuration property proxyPort.

Constructor Summary

GenericProxyHandler()

Method Summary

MapPage	getMapper() Return a reference to our page mapper, to allow futzing with the page maps from the outside
boolean	init(Server server, String prefix) Do one-time setup.
boolean	isMine(Request request) See if this is one of my requests.
byte[]	modifyContent(Request request, byte[] content) Rewrite the links in an html file so they resolve correctly in proxy mode.
boolean	respond(Request request) If this is one of "our" url's, fetch the document from the destination server, and return it as if it was local.

Methods inherited from class java.lang.Object

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

Field Detail

PREFIX

public static final String PREFIX

Handler configuration property prefix. Only URL's that begin with this string are considered by this handler. The default is (/).

See Also:

Constant Field Values

HOST

public static final String HOST

Handler configuration property host. The actual host site to appear on our site (required)

See Also:

Constant Field Values

PORT

public static final String PORT

Handler configuration property port. The actual port on the host site (defaults to defaultPort).

See Also:

Constant Field Values

PROXY_HOST

public static final String PROXY_HOST

Handler configuration property proxyHost. The name of a proxy to use (if any) to get to the host.

See Also:

Constant Field Values

PROXY_PORT

public static final String PROXY_PORT

Handler configuration property proxyPort. The proxy port to use to get to the host. defaults to defaultPort.

See Also:

Constant Field Values

NL

public static final String NL

See Also:

Constant Field Values

Constructor Detail

GenericProxyHandler

public GenericProxyHandler()

Method Detail

init

public boolean init(Server server,
                    String prefix)

Do one-time setup. get and process the handler properties. we can contact the server identified by the host parameter.

Specified by:

init in interface Handler

Parameters:

server - The HTTP server that created this Handler. Typical Handlers will use Server.props to obtain run-time configuration information.

prefix - The handlers name. The string this Handler may prepend to all of the keys that it uses to extract configuration information from Server.props. This is set (by the Server and ChainHandler) to help avoid configuration parameter namespace collisions.

Returns:

true if this Handler initialized successfully, false otherwise. If false is returned, this Handler should not be used.

respond

public boolean respond(Request request)
                throws IOException

If this is one of "our" url's, fetch the document from the destination server, and return it as if it was local.

Specified by:

respond in interface Handler

Parameters:

request - The Request object that represents the HTTP request.

Returns:

true if the request was handled. A request was handled if a response was supplied to the client, typically by calling Request.sendResponse() or Request.sendError.

Throws:

IOException - if there was an I/O error while sending the response to the client. Typically, in that case, the Server will (try to) send an error message to the client and then close the client's connection.

The IOException should not be used to silently ignore problems such as being unable to access some server-side resource (for example getting a FileNotFoundException due to not being able to open a file). In that case, the Handler's duty is to turn that IOException into a HTTP response indicating, in this case, that a file could not be found.

isMine

public boolean isMine(Request request)

See if this is one of my requests. This method can be overridden to do more sophisticated mappings.

Parameters:

request - The standard request object

getMapper

public MapPage getMapper()

Return a reference to our page mapper, to allow futzing with the page maps from the outside

modifyContent

public byte[] modifyContent(Request request,
                            byte[] content)

Rewrite the links in an html file so they resolve correctly in proxy mode.

Parameters:

request - The original request to this "proxy"

content - The content that needs to be rewritten.

Returns:

true if the headers and content should be sent to the client, false otherwise Modifies "headers" as a side effect