Class UrlMapperHandler

java.lang.Object
sunlabs.brazil.handler.UrlMapperHandler
All Implemented Interfaces:
Handler
public class UrlMapperHandler extends Object implements Handler
Handler for mapping URL's or HTTP headers, or redirecting URLs based on the contents of the current HTTP request. Matches URL's (or arbitrary request properties) against a regexp pattern. If there is a match, the URL (or specified HTTP header) is rewritten or the URL is redirected.

Properties:

match
The regexp to match a url. May contain constructs of the form ${xxx}, which are replaced by the value of request.props for the key xxx
replace
The url to replace it with. This may contain both regular expression sub-patterns, such as "\1", or variables of the form ${..} which are replaced with the equivalent request properties.
export
If set, use this as a properties prefix, and set request properties for each sub-expression in "match". (E.g. [export]1 [export]2 ...).
redirect
If set, the request is redirected instead of being rewritten
ignoreCase
If set, the case of the expression is ignored.
source
If set, then this string is used instead of the url as the source of the match. Variable substitution using ${xxx} is performed on source, which, if unset, defaults to "${url}". If set, ${} substitutions "method", "url", "protocol", "query", and "serverUrl" are taken from the current Request object. Then names in the Http Request headers are used, then names from the Request.props. The source property is obtained at init time, but evaluated (for ${...}) at every request.

As an example, the configuration:
prefix.source=${user-agent}!${url}
prefix.match=Lynx.*!(.*)
prefix.replace=/text\\1
 could cause all browsers with "Lynx" in their user agent header to the "text" sub-directory.

target
By default, this handler modifies the request URL. If target is specified, it names an HTTP header to be replaced instead of the URL. The "target" is ignored if "redirect" is specified, and a new header is created if the "target" header doesn't already exist.
Version:
2.6, 07/03/26
Author:
Stephen Uhler

  • Constructor Details

    • UrlMapperHandler

      public UrlMapperHandler()

  • Method Details

    • init

      public boolean init(Server server, String prefix)
      Description copied from interface: Handler
      Initializes the handler.
      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 request matches the expression, rewrite it.
      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.