@Inject Provider<ResourceSet> resourceSetProvider 
	@Inject extension ISerializer

	val resourceSet = resourceSetProvider.get
	val resource =resourceSet.createResource(URI.createURI("dummy.stext"))
	resource.contents += model	
    resource.contents.head.serialize(SaveOptions.newBuilder().format.options)

// bind your customized web resource set provider in the web module

def Class<? extends IWebResourceSetProvider> bindIWebResourceSetProvider() {
	MyResourceSetProvider
}

// your resource set provider for the web: `MyResourceSetProvider.xtend`

import com.google.inject.Inject
import com.google.inject.Provider
import org.eclipse.emf.ecore.resource.ResourceSet
import org.eclipse.xtext.web.server.IServiceContext
import org.eclipse.xtext.web.server.model.IWebResourceSetProvider

class MyResourceSetProvider implements IWebResourceSetProvider {
	
	@Inject Provider<ResourceSet> provider
	
	// ...

	@Override
	override get(String resourceId, IServiceContext serviceContext) {
                // ...
		return provider.get
	}
	
	// ...
}

Injector injector = new MyDslStandaloneSetup().createInjectorAndDoEMFRegistration();
IResourceFactory resourceFactory = injector.getInstance(IResourceFactory.class);
Provider<XtextResourceSet> xtextResourceSetProvider = injector.getInstance(new Key<Provider<XtextResourceSet>>() {});

XtextResourceSet resourceSet = xtextResourceSetProvider.get();

Resource resource = resourceFactory.createResource(URI.createURI(UUID.randomUUID() + ".mydsl"));
resourceSet.getResources().add(resource);
resource.load(new StringInputStream(body), null);
final EObject astRoot = resource.getContents().isEmpty() ? null : resource.getContents().get(0);

new ObjectMapper().writeValueAsString(astRoot)