Class GenericProxyHandler

java.lang.Object
sunlabs.brazil.handler.GenericProxyHandler
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.
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 Details

    • prefix

      protected String prefix

    • mapper

      protected MapPage mapper

    • host

      protected String host

    • port

      protected int port

    • proxyHost

      protected String proxyHost

    • proxyPort

      protected int proxyPort

    • urlPrefix

      protected String urlPrefix

    • requestPrefix

      protected String requestPrefix

    • tokens

      protected String tokens

    • passHost

      protected boolean passHost

    • noErrorReturn

      protected boolean noErrorReturn

    • 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:

    • HOST

      public static final String HOST
      Handler configuration property host. The actual host site to appear on our site (required)
      See Also:

    • PORT

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

    • 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:

    • PROXY_PORT

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

    • NL

      public static final String NL
      See Also:

  • Constructor Details

    • GenericProxyHandler

      public GenericProxyHandler()

  • Method Details

    • 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.

    • 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