根据随响应返回的请求修改设置标记

Question

基本上，我的问题很简单。我使用改造作为与我无法控制的服务器进行通信的框架。我想在我的请求上设置某种标记，该标记会自动在响应中返回。关于如何实现这一点有什么想法吗？

Answer 1

我找到了一种复杂且不太酷的方法来做到这一点。

0. 在请求和响应类型中添加标签字段

1.自定义okhttp3.RequestBody添加标签字段：

2.自定义okhttp3.ResponseBody添加标签字段：

3.自定义Converter.Factory设置和获取标签：
例如我对GsonResponseBodyConverterand做了一些更改GsonRequestBodyConverter：

TagGsonRequestBodyConverter.java：

@Override public RequestBody convert(T value) throws IOException {
    Buffer buffer = new Buffer();
    Writer writer = new OutputStreamWriter(buffer.outputStream(), UTF_8);
    JsonWriter jsonWriter = gson.newJsonWriter(writer);
    adapter.write(jsonWriter, value);
    jsonWriter.close();

    TagRequestBody requestBody = TagRequestBody.create(MEDIA_TYPE, buffer.readByteString());
    requestBody = value.tag;//just for example ,you will need to check type here
    return requestBody;
  }

TagGsonResponseBodyConverter.java：

    @Override public T convert(ResponseBody source) throws IOException {
try {
  //the ugly part,for that retrofit will wrap the responseBody with ExceptionCatchingRequestBody.(ExceptionCatchingRequestBody extends ResponseBody) 
  ResponseBody value = source;
  if (value.getClass().getSimpleName().equals("ExceptionCatchingRequestBody")){
    ResponseBody temp = null;
    try {
      Field f = source.getClass().getDeclaredField("delegate");
      f.setAccessible(true);
      temp = (T) f.get(value);
    } catch (Exception e) {
      e.printStackTrace();
    }
    value = temp != null?temp:value;
  }
  T t = adapter.fromJson(source.charStream());
  if (value instanceof TagResponseBody) {
    t.tag = ((TagResponseBody)value).tag;
  }
  return t;
} finally {
  value.close();
}

}

4.创建retrofit的okhttpClient时添加Interceptor，将标签从TagRequestBody传递到TagResponseBody：

.addInterceptor(new Interceptor() {
                    @Override
                    public Response intercept(Chain chain) throws IOException {
                        Response response = chain.proceed(chain.request());
                        if (request.body() instanceof TagRequestBody) {
                            TagResponseBody responseBody = new TagResponseBody(response.body());
                            responseBody.arg = ((TagRequestBody) request.body()).arg;
                            response = response.newBuilder()
                                    .body(responseBody)
                                    .build();
                        }
                        return response;
                    }
                })

因此，标签由以下内容持有：
RequestDataWithTag -- CustGsonRequestBodyConverter --> RequestBodyWithTag -- Interceptor --> ResponseBodyWithTag -- CustGsonResponseBodyConverter --> ResponseDataWithTag