Excited to share this! I've worked ~ a week solving this, finally have the best Answer.
First: Try to use Jersey
The osgi-jax-rs-connector suggested by kallada is best, but I couldn't get it working on Sling 8. I lost a full day trying, all I have to show for it are spooky class not found errors and dependency issues.
Solution: The ResourceProvider
Bertrand's link is for Sling 9 only, which isn't released. So here's how you do it in Sling 8 and older!
Two Files:
The ResourceProvider
The purpose of this is only to listen to all requests at /service and then produce a "Resource" at that virtual path, which doesn't actually exist in the JCR.
@Component
@Service(value=ResourceProvider.class)
@Properties({
@Property(name = ResourceProvider.ROOTS, value = "service/image"),
@Property(name = ResourceProvider.OWNS_ROOTS, value = "true")
})
public class ImageResourceProvider implements ResourceProvider {
@Override
public Resource getResource(ResourceResolver resourceResolver, String path) {
AbstractResource abstractResource;
abstractResource = new AbstractResource() {
@Override
public String getResourceType() {
return TypeServlet.RESOURCE_TYPE;
}
@Override
public String getResourceSuperType() {
return null;
}
@Override
public String getPath() {
return path;
}
@Override
public ResourceResolver getResourceResolver() {
return resourceResolver;
}
@Override
public ResourceMetadata getResourceMetadata() {
return new ResourceMetadata();
}
};
return abstractResource;
}
@Override
public Resource getResource(ResourceResolver resourceResolver, HttpServletRequest httpServletRequest, String path) {
return getResource(resourceResolver , path);
}
@Override
public Iterator<Resource> listChildren(Resource resource) {
return null;
}
}
The Servlet
Now you just write a servlet which handles any of the resources coming from that path - but this is accomplished by handling any resources with the resource type which is produced by the ResourceProvider listening at that path.
@SlingServlet(
resourceTypes = TypeServlet.RESOURCE_TYPE,
methods = {"GET" , "POST"})
public class TypeServlet extends SlingAllMethodsServlet {
static final String RESOURCE_TYPE = "mycompany/components/service/myservice";
@Override
protected void doGet(SlingHttpServletRequest request, SlingHttpServletResponse response) throws ServletException, IOException {
final String [] pathParts = request.getResource().getPath().split("/");
final String id = pathParts[pathParts.length-1];
response.setContentType("text/html");
PrintWriter out = response.getWriter();
try {
out.print("<html><body>Hello, received this id: " + id + "</body></html>");
} finally {
out.close();
}
}
}
Obviously your servlet would do something much more clever, such as process the "path" String more intelligently and probably produce JSON.