bug: the request body is not rewrited in plugin : ext-plugin-post-req

[gaoxingliang]

Issue description

I have a env ：
wolf --> ext-plugin-post-req (decrypt the request)-> my upstream (python) ---> ext-plugin-post-resp (encrypt the response)

but when I check the content in my upstream, the body is still encrypted.

my post-req filter:
logger.info("input headers:{}, raw input:{}", request.getHeaders(), request.getBody());
        User user = userService.tryFindUser(request.getHeader(Constants.HEADER_USER_ID));
        if (user == null) {
            response.setStatusCode(403);
            response.setBody(ERROR_NOT_FOUND);
            logger.warn("未找到用户：{}", request.getHeaders());
        } else {
            try {
                String decryptedBody = userService.decryptBody(request.getBody(), user);
                request.setBody(decryptedBody);
                request.setHeader(HEADER_REQUESTBODY_ENCRYPTED_FLAG, "true");
                logger.info("DecryptRequestFilter：request:{}, user：{}，{}", request.getRequestId(), user.getUserid(), decryptedBody);
            } catch (Exception e) {
                logger.error("decrypt request failure", e);
                response.setStatusCode(400);
                response.setBody(ERROR_DECRYPT_REQUEST_FAILURE);
            }
        }

and related log(you can see the request body is decrypted successfully.)

but the log in my python code(it says it's still encrypted )

my post-resp filter:
String userId = request.getUpstreamHeaders().get(Constants.HEADER_USER_ID);
        logger.info("Current user id : {}, {}, body from upstream:{}", userId, request.getUpstreamHeaders(), request.getBody());
        User user = userService.tryFindUser(userId);
        if (user == null) {
            response.setStatusCode(403);
            response.setBody(Constants.ERROR_NOT_FOUND);
            logger.warn("not found the user, maybe disabled. wolfuserid: {}", userId);
        } else {
            String encryptedBody = userService.encryptBody(request.getBody(), user);
            response.setBody(encryptedBody);
            response.setHeader(Constants.HEADER_RESPONSEBODY_ENCRYPTED_FLAG, "true");
            response.setStatusCode(request.getUpstreamStatusCode());
            logger.info("EncryptResponseFilter success：user(wolf)：{}，{}", user.getUserid(), encryptedBody);
        }

Environment

runner:0.0.4

Minimal test code / Steps to reproduce the issue

What's the actual result? (including assertion message & call stack if applicable)

What's the expected result?

the post-req filter should change the body sent to upstream.

[gaoxingliang]

I found the apisix supports rewrite the request body since 3.6.0. apache/apisix#9990
Does the java plugin runner need any changes to support this?

[gaoxingliang]

The source code has to be changed to make it work.
Some reference: #254
I have a fully working example at:
https://github.com/gaoxingliang/apisix-java-plugin-runner/blob/encrypt-response/readme-new.md

[monkeyDluffy6017]

Would you like to create a pr?