GZipped Request in OkHttp using Interceptors

gistfile1.java

// Not sure about this but uses a combination of the two:
// https://github.com/square/okhttp/issues/350
// https://android.googlesource.com/platform/external/okhttp/+/e78f117bcbd6b57d783737107f445ef75ecb474a/samples/guide/src/main/java/com/squareup/okhttp/recipes/RequestBodyCompression.java
public Response proceedGzip(Interceptor.Chain chain) throws IOException {
    Request originalRequest = chain.request();
    Request compressedRequest = originalRequest.newBuilder()
            .header("Content-Encoding", "gzip")
            .method(originalRequest.method(), requestBodyWithContentLength(gzip(originalRequest.body())))
            .build();
    return chain.proceed(compressedRequest);
}

private RequestBody requestBodyWithContentLength(final RequestBody requestBody) throws IOException {
    final Buffer buffer = new Buffer();
    try {
        requestBody.writeTo(buffer);
    } catch (IOException e) {
        throw new IOException("Unable to copy RequestBody");
    }
    return new RequestBody() {
        @Override
        public MediaType contentType() {
            return requestBody.contentType();
        }

        @Override
        public long contentLength() {
            return buffer.size();
        }

        @Override
        public void writeTo(BufferedSink sink) throws IOException {
            sink.writeAll(buffer);
        }
    };
}

private RequestBody gzip(final RequestBody body) {
    return new RequestBody() {
        @Override
        public MediaType contentType() {
            return body.contentType();
        }

        @Override
        public long contentLength() {
            return -1; // We don't know the compressed length in advance!
        }

        @Override
        public void writeTo(BufferedSink sink) throws IOException {
            BufferedSink gzipSink = Okio.buffer(new GzipSink(sink));
            body.writeTo(gzipSink);
            gzipSink.close();
        }
    };
}