Class RewriteHandler

All Implemented Interfaces:
Handler, Handler.Container, Handler.Singleton, Request.Handler, Container, Destroyable, Dumpable, Dumpable.DumpableContainer, LifeCycle, Invocable

public class RewriteHandler extends Handler.Wrapper

RewriteHandler rewrites incoming requests through a set of Rules.

RewriteHandler can rewrite the request URI, but also HTTP cookies and HTTP headers. When a rule matches, RewriteHandler can perform actions such as redirect to a different URI or directly produce a response with a configurable HTTP status code.

Rules can be grouped into a RuleContainer, which is itself a Rule. If the container rule matches (for example, virtual host name when using VirtualHostRuleContainer), then the contained rules will be applied.

Rules are applied in the same sequence they are added to the container. If a rule matches, it applies some logic (typically wrapping the request), and the next rule is invoked (with the wrapped request), until a terminating rule is found, or all the rules have been processed.

Request URI matching is performed either via Servlet pattern matching (using PatternRule subclasses), via regular expression matching (using RegexRule subclasses), or by a custom implementation of Rule.

  • Constructor Details

    • RewriteHandler

      public RewriteHandler()
    • RewriteHandler

      public RewriteHandler(RuleContainer rules)
    • RewriteHandler

      public RewriteHandler(Handler handler)
    • RewriteHandler

      public RewriteHandler(Handler handler, RuleContainer rules)
  • Method Details

    • getRuleContainer

      public RuleContainer getRuleContainer()
      Get the RuleContainer used by this handler.
      Returns:
      the RuleContainer used by this handler
    • getRules

      public List<Rule> getRules()
      Returns:
      the list of Rules.
    • setRules

      public void setRules(List<Rule> rules)

      Sets the list of rules, discarding the previous ones.

      Parameters:
      rules - the list of Rules to set
    • addRule

      public void addRule(Rule rule)

      Adds a Rule to the existing ones.

      Parameters:
      rule - the rule to add to the rules list
    • clear

      public void clear()

      Removes all the rules.

    • getOriginalPathAttribute

      public String getOriginalPathAttribute()
      See Also:
    • setOriginalPathAttribute

      public void setOriginalPathAttribute(String originalPathAttribute)
      See Also:
    • handle

      public boolean handle(Request request, Response response, Callback callback) throws Exception
      Description copied from interface: Request.Handler

      Invoked to handle the passed HTTP request and response.

      The request is accepted by returning true, then handling must be concluded by completing the passed callback. The handling may be asynchronous, i.e. this method may return true and complete the given callback later, possibly from a different thread. If this method returns false, then the callback must not be invoked and any mutation on the response reversed.

      Exceptions thrown by this method may be subsequently handled by an error Request.Handler, if present, otherwise a default HTTP 500 error is generated and the callback completed while writing the error response.

      The simplest implementation is:

       public boolean handle(Request request, Response response, Callback callback)
       {
           callback.succeeded();
           return true;
       }
       

      A HelloWorld implementation is:

       public boolean handle(Request request, Response response, Callback callback)
       {
           response.write(true, ByteBuffer.wrap("Hello World\n".getBytes(StandardCharsets.UTF_8)), callback);
           return true;
       }
       
      Specified by:
      handle in interface Request.Handler
      Overrides:
      handle in class Handler.Wrapper
      Parameters:
      request - the HTTP request to handle
      response - the HTTP response to handle
      callback - the callback to complete when the handling is complete
      Returns:
      True if and only if the request will be handled, a response generated and the callback eventually called. This may occur within the scope of the call to this method, or asynchronously some time later. If false is returned, then this method must not generate a response, nor complete the callback.
      Throws:
      Exception - if there is a failure during the handling. Catchers cannot assume that the callback will be called and thus should attempt to complete the request as if a false had been returned.