PostLargeProblem.java

// for more than 4K locations or for slow network you need to gzip the body

OkHttpClient client = new OkHttpClient();
client.setConnectTimeout(20, TimeUnit.SECONDS);
client.setReadTimeout(20, TimeUnit.SECONDS);
client.interceptors().add(new GzipRequestInterceptor());

....
  

class GzipRequestInterceptor implements Interceptor {
    @Override
    public com.squareup.okhttp.Response intercept(Interceptor.Chain chain) throws IOException {
        com.squareup.okhttp.Request originalRequest = chain.request();
        if (originalRequest.body() == null || originalRequest.header("Content-Encoding") != null) {
            return chain.proceed(originalRequest);
        }

        com.squareup.okhttp.Request compressedRequest = originalRequest.newBuilder()
                .header("Content-Encoding", "gzip")
                .method(originalRequest.method(), forceContentLength(gzip(originalRequest.body())))
                .build();
        return chain.proceed(compressedRequest);
    }

    /**
     * https://github.com/square/okhttp/issues/350
     */
    private RequestBody forceContentLength(final RequestBody requestBody) throws IOException {
        final Buffer buffer = new Buffer();
        requestBody.writeTo(buffer);
        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.write(buffer.snapshot());
            }
        };
    }

    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();
            }
        };
    }
}

PostLargeProblemForOkHttp3.java

class PostLargeProblemForOkHttp3 {
    public static void main(String[] args) throws IOException {
        okhttp3.OkHttpClient client = new okhttp3.OkHttpClient.Builder().connectTimeout(30, TimeUnit.SECONDS).
                readTimeout(30, TimeUnit.SECONDS).addInterceptor(new GzipRequestInterceptor3()).build();

        okhttp3.Request req = new okhttp3.Request.Builder().url("https://graphhopper.com/api/1/vrp/optimize?key=" + KEY).
                post(okhttp3.RequestBody.create(okhttp3.MediaType.parse("application/json"), new File("vrp.json"))).build();
        System.out.println(client.newCall(req).execute().body().string());
    }


    static class GzipRequestInterceptor3 implements okhttp3.Interceptor {
        @Override
        public okhttp3.Response intercept(okhttp3.Interceptor.Chain chain) throws IOException {
            okhttp3.Request originalRequest = chain.request();
            if (originalRequest.body() == null || originalRequest.header("Content-Encoding") != null) {
                return chain.proceed(originalRequest);
            }

            okhttp3.Request compressedRequest = originalRequest.newBuilder()
                    .header("Content-Encoding", "gzip")
                    .method(originalRequest.method(), forceContentLength(gzip(originalRequest.body())))
                    .build();
            return chain.proceed(compressedRequest);
        }

        /**
         * https://github.com/square/okhttp/issues/350
         */
        private okhttp3.RequestBody forceContentLength(final okhttp3.RequestBody requestBody) throws IOException {
            final Buffer buffer = new Buffer();
            requestBody.writeTo(buffer);
            return new okhttp3.RequestBody() {
                @Override
                public okhttp3.MediaType contentType() {
                    return requestBody.contentType();
                }

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

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

        private okhttp3.RequestBody gzip(final okhttp3.RequestBody body) {
            return new okhttp3.RequestBody() {
                @Override
                public okhttp3.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();
                }
            };
        }
    }
}