Merge pull request #4665 from square/jwilson.0226.duplex_interceptors

Test that duplex works fine with interceptors

okhttp-testing-support/src/main/java/okhttp3/ForwardingRequestBody.java

@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2019 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okhttp3;
+
+import java.io.IOException;
+import javax.annotation.Nullable;
+import okio.BufferedSink;
+
+public class ForwardingRequestBody extends RequestBody {
+  private final RequestBody delegate;
+
+  public ForwardingRequestBody(RequestBody delegate) {
+    if (delegate == null) throw new IllegalArgumentException("delegate == null");
+    this.delegate = delegate;
+  }
+
+  public final RequestBody delegate() {
+    return delegate;
+  }
+
+  @Override public @Nullable MediaType contentType() {
+    return delegate.contentType();
+  }
+
+  @Override public long contentLength() throws IOException {
+    return delegate.contentLength();
+  }
+
+  @Override public void writeTo(BufferedSink sink) throws IOException {
+    delegate.writeTo(sink);
+  }
+
+  @Override public boolean isDuplex() {
+    return delegate.isDuplex();
+  }
+
+  @Override public String toString() {
+    return getClass().getSimpleName() + "(" + delegate.toString() + ")";
+  }
+}

okhttp-testing-support/src/main/java/okhttp3/ForwardingResponseBody.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2019 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okhttp3;
+
+import javax.annotation.Nullable;
+import okio.BufferedSource;
+
+public class ForwardingResponseBody extends ResponseBody {
+  private final ResponseBody delegate;
+
+  public ForwardingResponseBody(ResponseBody delegate) {
+    if (delegate == null) throw new IllegalArgumentException("delegate == null");
+    this.delegate = delegate;
+  }
+
+  public final ResponseBody delegate() {
+    return delegate;
+  }
+
+  @Override public @Nullable MediaType contentType() {
+    return delegate.contentType();
+  }
+
+  @Override public long contentLength() {
+    return delegate.contentLength();
+  }
+
+  @Override public BufferedSource source() {
+    return delegate.source();
+  }
+
+  @Override public String toString() {
+    return getClass().getSimpleName() + "(" + delegate.toString() + ")";
+  }
+}

okhttp-testing-support/src/main/java/okhttp3/UppercaseRequestInterceptor.java

@@ -0,0 +1,52 @@
+/*
+ * Copyright (C) 2019 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okhttp3;
+
+import java.io.IOException;
+import okio.Buffer;
+import okio.BufferedSink;
+import okio.ByteString;
+import okio.ForwardingSink;
+import okio.Okio;
+import okio.Sink;
+
+/** Rewrites the request body sent to the server to be all uppercase. */
+public final class UppercaseRequestInterceptor implements Interceptor {
+  @Override public Response intercept(Chain chain) throws IOException {
+    return chain.proceed(uppercaseRequest(chain.request()));
+  }
+
+  /** Returns a request that transforms {@code request} to be all uppercase. */
+  private Request uppercaseRequest(Request request) {
+    RequestBody uppercaseBody = new ForwardingRequestBody(request.body()) {
+      @Override public void writeTo(BufferedSink sink) throws IOException {
+        delegate().writeTo(Okio.buffer(uppercaseSink(sink)));
+      }
+    };
+    return request.newBuilder()
+        .method(request.method(), uppercaseBody)
+        .build();
+  }
+
+  private Sink uppercaseSink(Sink sink) {
+    return new ForwardingSink(sink) {
+      @Override public void write(Buffer source, long byteCount) throws IOException {
+        ByteString bytes = source.readByteString(byteCount);
+        delegate().write(new Buffer().write(bytes.toAsciiUppercase()), byteCount);
+      }
+    };
+  }
+}

okhttp-testing-support/src/main/java/okhttp3/UppercaseResponseInterceptor.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2019 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package okhttp3;
+
+import java.io.IOException;
+import okio.Buffer;
+import okio.BufferedSource;
+import okio.ForwardingSource;
+import okio.Okio;
+
+/** Rewrites the response body returned from the server to be all uppercase. */
+public final class UppercaseResponseInterceptor implements Interceptor {
+  @Override public Response intercept(Chain chain) throws IOException {
+    return uppercaseResponse(chain.proceed(chain.request()));
+  }
+
+  private Response uppercaseResponse(Response response) {
+    ResponseBody uppercaseBody = new ForwardingResponseBody(response.body()) {
+      @Override public BufferedSource source() {
+        return Okio.buffer(uppercaseSource(delegate().source()));
+      }
+    };
+    return response.newBuilder()
+        .body(uppercaseBody)
+        .build();
+  }
+
+  private ForwardingSource uppercaseSource(BufferedSource source) {
+    return new ForwardingSource(source) {
+      @Override public long read(Buffer sink, long byteCount) throws IOException {
+        Buffer buffer = new Buffer();
+        long read = delegate().read(buffer, byteCount);
+        if (read != -1L) sink.write(buffer.readByteString().toAsciiUppercase());
+        return read;
+      }
+    };
+  }
+}

okhttp-tests/src/test/java/okhttp3/DuplexTest.java

@@ -442,6 +442,42 @@ public final class DuplexTest {
     mockDuplexResponseBody.awaitSuccess();
   }
 
+  @Test public void duplexWithRewriteInterceptors() throws Exception {
+    enableProtocol(Protocol.HTTP_2);
+    MockDuplexResponseBody mockDuplexResponseBody = enqueueResponseWithBody(
+        new MockResponse()
+            .clearHeaders(),
+        new MockDuplexResponseBody()
+            .receiveRequest("REQUEST A\n")
+            .sendResponse("response B\n")
+            .exhaustRequest()
+            .exhaustResponse());
+
+    client = client.newBuilder()
+        .addInterceptor(new UppercaseRequestInterceptor())
+        .addInterceptor(new UppercaseResponseInterceptor())
+        .build();
+
+    Call call = client.newCall(new Request.Builder()
+        .url(server.url("/"))
+        .post(new AsyncRequestBody())
+        .build());
+
+    try (Response response = call.execute()) {
+      BufferedSink requestBody = ((AsyncRequestBody) call.request().body()).takeSink();
+      requestBody.writeUtf8("request A\n");
+      requestBody.flush();
+
+      BufferedSource responseBody = response.body().source();
+      assertEquals("RESPONSE B", responseBody.readUtf8Line());
+
+      requestBody.close();
+      assertNull(responseBody.readUtf8Line());
+    }
+
+    mockDuplexResponseBody.awaitSuccess();
+  }
+
   private MockDuplexResponseBody enqueueResponseWithBody(
       MockResponse response, MockDuplexResponseBody body) {
     MwsDuplexAccess.instance.setBody(response, body);

okhttp/src/main/java/okhttp3/RequestBody.java

@@ -44,7 +44,8 @@ public abstract class RequestBody {
 
   /**
    * A duplex request body is special in how it is <strong>transmitted</strong> on the network and
-   * in the <strong>API contract</strong> between OkHttp and the application.
+   * in the <strong>API contract</strong> between OkHttp and the application. This method returns
+   * false unless it overridden by a subclass.
    *
    * <h3>Duplex Transmission</h3>
    *
@@ -54,19 +55,22 @@ public abstract class RequestBody {
    *
    * <p>Though any call may be initiated as a duplex call, only web servers that are specially
    * designed for this nonstandard interaction will use it. As of 2019-01, the only widely-used
-   * implementation of this pattern is gRPC.
+   * implementation of this pattern is <a
+   * href="https://github.com/grpc/grpc/blob/master/doc/PROTOCOL-HTTP2.md">gRPC</a>.
    *
-   * <p>Because the encoding of interleaved data is not well-defined for HTTP/1, duplex request bodies
-   * may only be used with HTTP/2. Calls to HTTP/1 servers will fail before the HTTP request is
-   * transmitted.
+   * <p>Because the encoding of interleaved data is not well-defined for HTTP/1, duplex request
+   * bodies may only be used with HTTP/2. Calls to HTTP/1 servers will fail before the HTTP request
+   * is transmitted. If you cannot ensure that your client and server both support HTTP/2, do not
+   * use this feature.
    *
    * <p>Duplex APIs</p>
    *
    * <p>With regular request bodies it is not legal to write bytes to the sink passed to {@link
-   * RequestBody#writeTo} after that method returns. For duplex sinks that condition is lifted. Such
-   * writes occur on an application-provided thread and may occur concurrently with reads of the
-   * {@link ResponseBody}. For duplex request bodies, {@link #writeTo} should return quickly,
-   * possibly by handing off the provided request body to another thread to perform writing.
+   * RequestBody#writeTo} after that method returns. For duplex requests bodies that condition is
+   * lifted. Such writes occur on an application-provided thread and may occur concurrently with
+   * reads of the {@link ResponseBody}. For duplex request bodies, {@link #writeTo} should return
+   * quickly, possibly by handing off the provided request body to another thread to perform
+   * writing.
    */
   public boolean isDuplex() {
     return false;