从响应中获取标头（改造/确定Http客户端）

Question

我在OkHttp客户端和Jackson上使用reform进行Json序列化，并希望获得响应的头。

我知道我可以扩展OkClient并拦截它。但这发生在反序列化过程开始之前。

我基本上需要的是获取头文件和反序列化的Json对象。

Answer 1

就像你一样，我希望标题在有效载荷的旁边。我需要进入Etag。这需要一些复古的食物，但你可以做到这一点。我是这么做的。这是一个不完整的样本，因此不要将其视为最佳实践样本。

public static RestAdapter.Builder getRestBuilder(Context context) {
    GsonBuilder gsonBuilder = GsonBuilderUtils.getBuilder();
    Gson gson = gsonBuilder.create();
    // **
    // 1. create our own custom deserializer here
    // **
    final MyGsonConverter gsonConverter = new MyGsonConverter(gson);
    OkHttpClient httpClient = MyPersonalOkHttpFactory.getInstance().getAuthHttpClient(context);
    httpClient.networkInterceptors().add(new Interceptor() {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request originalRequest = chain.request();
            Response response = chain.proceed(originalRequest);
            // **
            // 2. add the headers from the Interceptor to our deserializer instance
            // **
            gsonConverter.headers = response.headers();
            return response;
        }
    });
    RestAdapter.Builder builder = new RestAdapter.Builder()
            .setClient(new OkClient(httpClient))
            .setEndpoint(Common.getApiOriginUrl())
            .setConverter(gsonConverter);
    return builder;
}

private static class MyGsonConverter extends GsonConverter {

    private Headers headers;

    public MyGsonConverter(Gson gson) {
        super(gson);
    }

    @Override
    public Object fromBody(TypedInput body, Type type) throws ConversionException {
        Object obj =  super.fromBody(body, type);
        // **
        // 3. at this point, gson is called and you have access to headers
        // do whatever you want here. I just set it on the return object.
        // ** 
        if (obj instanceof HeadersArrayList) {
            ((HeadersArrayList)obj).setHeaders(headers);
        }
        return obj;
    }
}

public class HeadersArrayList<K> extends ArrayList<K>{

    private Headers headers;

    public Headers getHeaders() {
        return headers;
    }

    public void setHeaders(Headers headers) {
        this.headers = headers;
    }
}

// the retrofit api for reference
@GET("/api/of/my/backend/{stuff}")
HeadersArrayList<String> getSomething(@Path("stuff") String stuff);

Answer 2

在Retrofit 2.0.0中，您可以像这样获取标头：

public interface Api {
    @GET("user")
    Call<User> getUser();
}

Call<User> call = api.getUser();
call.enqueue(new Callback<User>() {
    @Override
    public void onResponse(Call<User> call, Response<User> response) {
        // get headers
        Headers headers = response.headers();
        // get header value
        String cookie = response.headers().get("Set-Cookie");
        // TODO
    }

    @Override
    public void onFailure(Call<User> call, Throwable t) {
        // TODO
    }
});

Answer 3

对于改型1.9.0，如果您使用接口的回调异步版本，

@GET("/user")
void getUser(Callback<User> callback)

然后，您的回调将收到一个响应对象

    Callback<User> user = new Callback<User>() {
        @Override
        public void success(User user, Response response) {

        }

        @Override
        public void failure(RetrofitError error) {

        }
    }

它有一个名为< code>getHeaders()的方法

    Callback<User> user = new Callback<User>() {
        @Override
        public void success(User user, Response response) {
            List<Header> headerList = response.getHeaders();
            for(Header header : headerList) {
                Log.d(TAG, header.getName() + " " + header.getValue());
            }
        }

对于 Retrofit 2.0 的界面，您可以使用 Call 执行此操作

对于Retrofit 2.0的Rx支持，您可以使用可观察执行此操作