报告基于Jersey的RESTful服务的进度

Question

I have a RESTful service developed using Jersey(Java) which does heavy lifting for a user including the multiple file transfer part of a single complete operation. I would like to provide some sort of progress notification to the client(user) using this service indicating what is going or what percent of the operation is done. Accuracy of the notification is not an issue. Given that this is a RESTful service, any thought how this could be achieved? Any existing sample might be helpful.

Update/clarification: This notification is like progress/status notification while the main operation is still in progress, since in certain scenarios the whole operation might take more than 5 minutes I want to make sure I update the client as to what is going on on the service side and why it is taking this long to fulfill the request.

Ex. Request ... status... status .... status.... final Response.

I am assuming that this is not going to happen on same Request/Response pipe, this might involve creating another communication pipe between client and service.

Answer 1

When I asked a similar question I was suggested to respond with HTTP 202 Accepted and provide an address of a newly created resource - a status of the operation:

HTTP 202 Accepted
Location: /jobs/statuses/<status_id>

Answer 2

You can return a json string with all the information. The way you generate the information for monitoring is up to you.

Here is an example of controller with json:

@RequestMapping(value = "/getblabla", method = RequestMethod.POST)
public @ResponseBody String getblabla(@RequestParam("json") String json,
    HttpServletRequest request) {

    // Do something

    return resJson;
}

Then you can use a library like Gson that has two main methods.

Here's how to map a json to an object:

 MyDto obj = gson.fromJson(json, MyDto.class);

Here's how to map an object to a Json:

String json = gson.toJson(obj);