ResCU - a lightweight Rest client utility for Java (JAX-RS)

ResCU enables the user to create a proxy Rest client in run-time directly from a JAX-RS annotated interface. ResCU is mostly focused on json-based services, and uses Jackson for json-to-object mapping.

Several other libraries do this (eg. Jersey and RESTEasy); the benefit of ResCU is that it is very lightweight with minimal dependencies. This makes it useful for quickly creating REST clients in Android apps etc.

Dependencies

jackson (json parser)
slf4j (logging interface)
jsr-311 (JAX-RS) (a set of REST-service specific annotations)
jsr-305 (a set of annotations)

Benefits

lightweight, minimal dependencies.
JAX-RS-annotated server-side interfaces may be reused to create clients; basic support is provided for @GET, @POST, @PUT, @DELETE, @HEAD, @OPTIONS, @Path, @QueryParam, @FormParam, @HeaderParam, @PathParam.
Support for basic HTTP authentication and some common request signing paradigms.
Support for exceptions on API methods.

Limitations

This is meant mostly for json-based REST services, ie. the response body is always interpreted as json. No XML.
JAX-RS: No support for @MatrixParam.

Logging

ResCU uses slf4j for logging. For best results, a supported logging implementation (eg. log4j, JUL, logback, ...) should be provided in runtime. See slf4j's documentation for more info.

Usage

Maven

Rescu is hosted in Maven Central so all you need to do is add this dependency to your pom:

<dependency>
    <groupId>com.github.mmazi</groupId>
    <artifactId>rescu</artifactId>
    <version>1.0.0</version>
</dependency>

Usage in code

Create a JAX-RS-annotated interface (or get it from the REST service developer), eg. ExampleService.java.
Call ExampleService service = RestProxyFactory.createProxy(ExampleService.class, "http://www.example.com/").
That's it! Just use the service object you just got.

For several working examples, see XChange, eg. BitstampPollingTradeService.java.

Settings

Rescu can be configured by adding a rescu.properties file in your classpath.

Supported settings with example values (copy this into your rescu.properties file):

rescu.http.readTimeoutMillis = 5000             # Read timeout in milliseconds when performing HTTP requests. The default is 30000 (30 seconds).
rescu.http.readProxyHost = www.example.com      # HTTP proxy host. Both host and port must be set in order to use a proxy.
rescu.http.readProxyPort = 80                   # HTTP proxy port. Both host and port must be set in order to use a proxy.

Important note:

I am very open to new suggestions, change requests etc. If ResCU seems almost right for you, but not quite, do write me a note, eg. by opening an issue.

dominicwilliams/rescu