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RestExpress is the easiest way to create RESTful web services in Java. An extremely Lightweight, Fast, REST Engine and API for Java. Supports JSON and XML serialization automagically as well as ISO 8601 date formats. A thin wrapper on Netty IO HTTP handling, RestExpress lets you create performant, stand-alone REST web services rapidly. Works 'ex…
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RestExpress is a thin wrapper on the JBOSS Netty HTTP stack to provide a simple and easy way to create RESTful services in Java that support massive Internet Scale and performance.

Born to be simple, only three things are required to wire up a service: 1) The main class which utilizes the RestExpress DSL to create a server instance. 2) A RouteDeclaration extender (much like routes.rb in a Rails app), which uses a DSL for the declaration of supported URLs and HTTP methods of the service(s) in its defineRoutes() method. 3) Service implementation(s), which is/are a simple POJO--no interface or super class implementation.

See: examples/kickstart directory to get started (there is a README there).

RestExpress supports both JSEND-style and raw responses. Meaning that it can wrap responses so AJAX clients can always process the responses easily. Or it can simply marshal the service return value directly into JSON or XML. For more information on JSEND-style responses, see:

A quick tutorial:

Please see the Kickstart application in examples/kickstart for a complete, running example.

  • HTTP Methods, if not changed in the fluent (DSL) interface, map to the following: 1) GET --> read(Request, Response) 2) PUT --> update(Request, Response) 3) POST --> create(Request, Response) 4) DELETE --> delete(Request, Response)

You can choose to return objects from the methods, if desired, which will be returned to the client as body of the response. The object will be marshaled into JSON or XML, depending on the default or based on the format in the request (e.g. '.xml' or '?format=xml').

If you choose to not return a value from the method (void methods) and using raw responses, then call response.setResponseNoContent() before returning to set the response HTTP status code to 204 (no content). Wrapped responses (JSEND style) are the default. So if you're using wrapped responses, there will always be a response returned to the client--therefore, you don't need to set the response.setResponseNoContent(). Just return your objects--or not. RestExpress will handle things on your behalf!

On successful creation, call response.setResponseCreated() to set the returning HTTP status code to 201.

BTW, if you're on a Mac or Linux box, you can do the following to get Ruby on Rails "scaffolding" -like behavior by running the following from the RestExpress root directory: 1) ant release 2) ./src/scripts/ 3) cd (e.g. '~/src') 4) /src/scripts/ (e.g. Sample) 5) cd (e.g. Sample) 6) ant run

From another console, enter something like the following to test your new service suite: 1) curl -i localhost:8081/sample/42

You should see something like this: HTTP/1.1 404 Not Found Content-Type: application/json; charset=UTF-8 Content-Length: 115

{"code":404,"status":"error","message":"The order ID you requested was not found: 42","data":"NotFoundException"}

Change History/Release Notes:

Release 0.8.0 - in development (branch 'master')

  • Changed to support multiple response types with wrapping or not, etc. Now can support wrapped JSON (.wjson) and XML (.wxml) as well as un-wrapped JSON (.json) and XML (.xml) depending on the format specifier.
  • Now throws BadRequestException (400) if the specified format (e.f. .json) isn't supported by the service suite.
  • Now throws MethodNotAllowedException (405) if the requested URL matches a route but not for the requested HTTP method. Sets the HTTP Allow header to a comma-delimited list of accepted methods.
  • Removed StringUtils.parseQueryString() as it was previously deprecated--use QueryStringParser.
  • Introduced String.join() methods (2).
  • Removed JSONP handling, favoring use of CORS instead, introducing CorsHeaderPlugin and corresponding post-processor.
  • Wraps ETAG header in quotes.
  • Renamed QueryRange.stop to QueryRange.limit.
  • Removed need for RouteDefinition class, moving that functionality into the RestExpress builder.
  • Changed example apps to reflect above elimination of RouteDefinition class.

Release 0.7.2 - 14 May 2012

  • Introduced ExecutionHandler with configuration via RestExpress.setExecutorThreadCount(int) to off-load long-running requests from the NIO workers into a separate thread pool.
  • Introduced CacheControlPlugin which leverages CacheHeaderPostprocessor, DateHeaderPostprocessor and EtagHeaderPostprocessor to respond to GET requests.
  • Introduced EtagHeaderPostprocessor which adds ETag header in response to GET requests.
  • Introduced DateHeaderPostprocessor which adds a Date header to responses to GET requests.
  • Introduced CacheHeaderPostprocessor which support Cache-Control and other caching-related response header best-practices by setting Parameters.Cache.MAX_AGE or Flags.Cache.DONT_CACHE on a route.
  • Changed to use QueryStringParser over StringUtils for query-string and QueryStringDecoder for body parsing. This mitigates HashDoS attacks, since the query-string is parsed before a request is accepted.
  • Deprecated StringUtils in favor of using Netty's QueryStringDecoder or RestExpress's QueryStringParser.
  • Refactored so SerializationProcessor.resolve(Request) is only called once at the end of the request cycle (performance enhancement).

Release 0.7.1 - 20 Sep 2011

  • Added rootCause to ResultWrapper data area.
  • Exposed the XStream object from DefaultXmlProcessor.
  • Renamed Link to XLink.
  • Renamed LinkUtils to XLinkUtils, adding asXLinks() method that utilizes XLinkFactory callback to create the XLink instances.
  • Changed URL Matching to support additional characters: '[', ']', '&' which more closely follows W3C the specification.
  • Added ability to return query string parameters as a Map from the Request.
  • Introduced Request.getBaseUrl() which returns protocol and host, without URL path information.
  • Introduced query criteria capability: filter, order, range (for pagination).
  • Introduced the concept of Plugins.
  • Refactored the console routes to use the new plugin concept.
  • Updated Netty jars (to 3.2.5).
  • Added ability to set the number of worker threads via call to RestExpress.setWorkerThreadCount() before calling bind().

Release 0.7.0

  • Added gzip request/response handling. On by default. Disable it via call to RestExpress.noCompression() and supportCompression().
  • Added chunked message handling. On by default. Chunking settings are managed via RestExpress.noChunkingSupport(), supportChunking(), and setMaxChunkSize(int).

Release - 31 Mar 2011

  • Bug fix to patch erroneously writing to already closed channel in DefaultRequestHandler.exceptionCaught().

Release 0.6.1 - 30 Mar 2011

  • Stability release.
  • Fixed issue when unable to URL Decode query string parameters or URL.
  • Introduced SerializationResolver that defines a getDefault() method. Implemented SerializationResolver in DefaultSerializationResolver.
  • Changed UrlPattern to match format based on non-whitespace vs. word characters.
  • Refactored Request.getHeader() into getRawHeader(String) and getUrlDecodedHeader(String), along with corresponding getRawHeader(String,String) and getUrlDecodedHeader(String,String).
  • Renamed realMethod property to effectiveHttpMethod, along with appropriate accessor/mutator.
  • Removed Request from Response constructor signature.
  • Added FieldNamingPolicy to DefaultJsonProcessor (using LOWER_CASE_WITH_UNDERSCORES).
  • getUrlDecodedHeader(String) throws BadRequestException if URL decoding fails.

Release - 21 Mar 2011

  • Fixed issue with 'connection reset by peer' causing unresponsive behavior.
  • Utilized Netty logging behavior to add logging capabilities to RestExpress.
  • Made socket-level settings externally configurable: tcpNoDelay, KeepAlive, reuseAddress, soLinger, connectTimeoutMillis, receiveBufferSize.
  • Merged in path release changes.
  • Added enforcement of some HTTP 1.1 specification rules: Content-Type, Content-Length and body content for 1xx, 204, 304 are not allow. Now throws HttpSpecificationException if spec. is not honored.
  • Added ability to add 'flags' and 'parameters' to routes, in that, uri().flag("name") on Route makes test request.isFlagged("name") return true. Also, uri().parameter("name", "value") makes request.getParamater("name") return "value". Not returned/marshaled in the response. Useful for setting internal values/flags for preprocessors, controllers, etc.
  • Added .useRawResponse() and .useWrappedResponse() to fluent route DSL. Causes that particular route to wrap the response or not, independent of global response wrap settings.
  • Parameters parsed from the URL and query string arguments are URL decoded before being placed as Request headers.


  • Issue #7 - Fixed issue with invalid URL requested where serialization always occurred to the default (JSON). Now serializes to the requested format, if applicable.
  • Issue #11 - Feature enhancement for Kickstart. Now utilizes Rails-inspired configuration environements (e.g. dev, testing, prod, etc.).
  • Issue #12 - Parse URL parameter names out of the URL pattern and include them in the route metadata output.

Release 0.6.0

  • Routes now defined in descendant of RouteDeclaration.
  • Refactored everything into RestExpress object, using builder pattern for configuration.
  • Implemented RestExpress DSL to declare REST server in main().
  • Added supported formats and default format to RouteBuilder.
  • Added JSEND-style response wrapping (now default). Call RestExpress.useWrappedResponses() to use.
  • Add ability to support raw response return. Call RestExpress.useRawResponses() to use.
  • Implemented /console/routes.{format} route which return metadata about the routes in this service suite. To use, call RestExpress.supportConsoleRoutes().
  • Exceptions occurring now return in the requested format with the message wrapped and using the appropriate mime type (e.g. application/json or application/xml).
  • Kickstart application has complete build with 'dist' target that builds a runnable jar file and 'run' target that will run the services from the command line.
  • Kickstart application now handles JVM shutdown correctly using JVM shutdown hooks. The method RestExpress.awaitShutdown() uses the DefaultShutdownHook class. RestExpress.shutdown() allows programs to use their own shutdown hooks, calling RestExpress.shutdown() upon shudown to release all resource.

Release - 11 Mar 2011

  • Patch release to fix issue with HTTP response status of 204 (No Content) and 304 (Not Modified) where they would return a body of an empty string and content length of 2 ('\r\n'). No longer serializes for 204 or 304. Also no longer serializes for null body response unless a JSONP header is passed in on the query string.

Release 0.5.6 - 18 Jan 2011

  • Upgraded to Netty 3.2.3 final.
  • Added getProtocol(), getHost(), getPath() to Request
  • Functionality of getUrl() is now getPath() and getUrl() now returns the entire URL string, including protocol, host and port, and path.

Release 0.5.5

  • Added regex URL matching with RouteMapping.regex(String) method.
  • Refactored Route into an abstract class, moving previous functionality into ParameterizedRoute.
  • Added KickStart release artifact to get projects going quickly--simply unzip the kickstart file.
  • Added SimpleMessageObserver which performs simple timings and outputs to System.out.

Release 0.5.4

  • Added alias() capability to DefaultTxtProcessor to facilitate custom text serialization.
  • Updated kickstart application to illustrate latest features.
  • Minor refactoring of constants and their locations (moved to

Release 0.5.3

  • Fixed issue with JSON date/timestamp parsing.
  • Fixed issues with XML date/timestamp parsing.
  • Upgraded to GSON 1.6 release.
  • Added correlation ID to Request to facilitate timing, etc. in pipeline.
  • Added alias(String, Class) to DefaultXmlProcessor.
  • By default, alias List and Link in DefaultXmlProcessor.

Release 0.5.2

  • Introduced DateJsonProcessor (sibling to DefaultJsonProcessor) which parses dates vs. time points.
  • Refactored ExceptionMapping.getExceptionFor() signature from Exception to Throwable.
  • Introduced MessageObserver, which accepts notifications of onReceived(), onSuccess(), onException(), onComplete() to facilitate logging, auditing, timing, etc.
  • Changed RouteResolver.resolve() to throw NotFoundException instead of BadRequestException for unresolvable URI.

Release 0.5.1

  • Enhanced support for mark, unreserved and some reserved characters in URL. Specifically, added $-+*()~:!' and %. Still doesn't parse URLs with '.' within the string itself--because of the support for .{format} URL section.

Release 0.5

  • Renamed repository from RestX to RestExpress.
  • Repackaged everything from com.strategicgains.restx... to com.strategicgains.restexpress...
  • Changed DefaultHttpResponseWriter to output resonse headers correctly.
  • Updated javadoc on RouteBuilder to provide some documentation on route DSL.

Release 0.4

  • Fixed error in "Connection: keep-alive" processing during normal and error response writing.
  • Can now create route mappings for OPTIONS and HEAD http methods.
  • Added decoding to URL when Request is constructed.
  • Improved pre-processor implementation, including access to resolved route in request.
  • Better null handling here and there to avoid NullPointerException, including serialization resolver.
  • Improved UT coverage.
  • KickStart application builds and is a more accurate template.

Release 0.3

  • Added support for "method tunneling" in POST via query string parameter (e.g. _method=PUT or _method=DELETE)
  • Added JSONP support. Use jsonp= in query string.
  • Utilized Builder pattern in DefaultPipelineFactory, which is now PipelineBuilder.
  • Externalized DefaultRequestHandler in PipelineBuilder and now supports pre/post processors (with associated interfaces).
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