sunlabs.brazil.handler
Class GenericProxyHandler

java.lang.Object
  extended by sunlabs.brazil.handler.GenericProxyHandler
All Implemented Interfaces:
Handler
Direct Known Subclasses:
MultiProxyHandler, ProxyPropertiesHandler

public class GenericProxyHandler
extends java.lang.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.
port
Host port to proxy to (defaults to 80).
proxyHost
Which proxy host to use (if any) to contact "host".
proxyPort
The proxy's port (defaults to 80)
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.

Version:
2.5, 07/03/21
Author:
Stephen Uhler

Field Summary
protected  java.lang.String host
           
static java.lang.String HOST
          Handler configuration property host.
protected  MapPage mapper
           
static java.lang.String NL
           
protected  boolean noErrorReturn
           
protected  boolean passHost
           
protected  int port
           
static java.lang.String PORT
          Handler configuration property port.
protected  java.lang.String prefix
           
static java.lang.String PREFIX
          Handler configuration property prefix.
static java.lang.String PROXY_HOST
          Handler configuration property proxyHost.
static java.lang.String PROXY_PORT
          Handler configuration property proxyPort.
protected  java.lang.String proxyHost
           
protected  int proxyPort
           
protected  java.lang.String requestPrefix
           
protected  java.lang.String tokens
           
protected  java.lang.String urlPrefix
           
 
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, java.lang.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.
protected  boolean shouldFilter(MimeHeaders headers)
          See if the content needs to be filtered.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

prefix

protected java.lang.String prefix

mapper

protected MapPage mapper

host

protected java.lang.String host

port

protected int port

proxyHost

protected java.lang.String proxyHost

proxyPort

protected int proxyPort

urlPrefix

protected java.lang.String urlPrefix

requestPrefix

protected java.lang.String requestPrefix

tokens

protected java.lang.String tokens

passHost

protected boolean passHost

noErrorReturn

protected boolean noErrorReturn

PREFIX

public static final java.lang.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 java.lang.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 java.lang.String PORT
Handler configuration property port. The actual port on the host site (defaults to 80).

See Also:
Constant Field Values

PROXY_HOST

public static final java.lang.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 java.lang.String PROXY_PORT
Handler configuration property proxyPort. The proxy port to use to get to the host. defaults to 80.

See Also:
Constant Field Values

NL

public static final java.lang.String NL
See Also:
Constant Field Values
Constructor Detail

GenericProxyHandler

public GenericProxyHandler()
Method Detail

init

public boolean init(Server server,
                    java.lang.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 java.io.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:
java.io.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.


shouldFilter

protected boolean shouldFilter(MimeHeaders headers)
See if the content needs to be filtered. Return "true" if "modifyContent" should be called

Parameters:
headers - Vector of mime headers for data to proxy

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"
headers - The vector of mime headers for the proxy request
Returns:
true if the headers and content should be sent to the client, false otherwise Modifies "headers" as a side effect