与 okhttp 分块的传输编码仅提供完整结果

Question

我正在尝试获得有关分块端点的一些见解，因此计划逐块打印服务器发送给我的内容。我没有这样做，所以我写了一个测试来查看 OkHttp/Retrofit 是否按我预期的那样工作。

下面的测试应该向控制台传送一些块，但我得到的只是完整的响应。

我什至让 OkHttp3 的 MockWebServer 向我发送块，我有点迷失了我所缺少的东西。

我找到了这个改造问题条目，但答案对我来说有点模棱两可：Chunked Transfer Encoding Response

class ChunkTest {
    @Rule
    @JvmField
    val rule = RxImmediateSchedulerRule() // custom rule to run Rx synchronously

    @Test
    fun `test Chunked Response`() {
        val mockWebServer = MockWebServer()
        mockWebServer.enqueue(getMockChunkedResponse())

        val retrofit = Retrofit.Builder()
                .baseUrl(mockWebServer.url("/"))
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create())
                .client(OkHttpClient.Builder().build())
                .build()
        val chunkedApi = retrofit.create(ChunkedApi::class.java)

        chunkedApi.getChunked()
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe({
                    System.out.println(it.string())
                }, {
                    System.out.println(it.message)
                })

        mockWebServer.shutdown()
    }

    private fun getMockChunkedResponse(): MockResponse {
        val mockResponse = MockResponse()
        mockResponse.setHeader("Transfer-Encoding", "chunked")
        mockResponse.setChunkedBody("THIS IS A CHUNKED RESPONSE!", 5)
        return mockResponse
    }
}

interface ChunkedApi {
    @Streaming
    @GET("/")
    fun getChunked(): Flowable<ResponseBody>
}

测试控制台输出：

Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer execute
INFO: MockWebServer[49293] starting to accept connections
Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer processOneRequest
INFO: MockWebServer[49293] received request: GET / HTTP/1.1 and responded: HTTP/1.1 200 OK
THIS IS A CHUNKED RESPONSE!
Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer acceptConnections
INFO: MockWebServer[49293] done accepting connections: Socket closed

我希望更像（正文 "cut" 每 5 个字节）：

Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer execute
INFO: MockWebServer[49293] starting to accept connections
Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer processOneRequest
INFO: MockWebServer[49293] received request: GET / HTTP/1.1 and responded: HTTP/1.1 200 OK
THIS
IS A 
CHUNKE
D RESPO
NSE!
Nov 06, 2018 4:08:15 PM okhttp3.mockwebserver.MockWebServer acceptConnections
INFO: MockWebServer[49293] done accepting connections: Socket closed

Answer 1

OkHttp Mockserver 确实对数据进行分块，但 LoggingInterceptor 似乎会等到整个分块缓冲区已满，然后才会显示它。

来自这个nice summary about HTTP streaming：

The use of Transfer-Encoding: chunked is what allows streaming within a single request or response. This means that the data is transmitted in a chunked manner, and does not impact the representation of the content.

考虑到这一点，我们正在处理 1 "request / response"，这意味着我们必须在获得整个响应之前进行块检索。然后将每个块推送到我们自己的缓冲区中，所有这些都在 OkHttp network interceptor.

上

这里有一个例子 NetworkInterceptor:

class ChunksInterceptor: Interceptor {

    val Utf8Charset = Charset.forName ("UTF-8")

    override fun intercept (chain: Interceptor.Chain): Response {
        val originalResponse = chain.proceed (chain.request ())
        val responseBody = originalResponse.body ()
        val source = responseBody!!.source ()

        val buffer = Buffer () // We create our own Buffer

        // Returns true if there are no more bytes in this source
        while (!source.exhausted ()) {
            val readBytes = source.read (buffer, Long.MAX_VALUE) // We read the whole buffer
            val data = buffer.readString (Utf8Charset)

            println ("Read: $readBytes bytes")
            println ("Content: \n $data \n")
        }

        return originalResponse
    }
}

那当然我们在OkHttp客户端上注册这个Network Interceptor

与 okhttp 分块的传输编码仅提供完整结果

Transfer Encoding chunked with okhttp only delivers full result

retrofit

rx-java2

okhttp3

chunked