org.graylog2.telemetry.okhttp.GzipRequestInterceptor Maven / Gradle / Ivy

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package org.graylog2.telemetry.okhttp;

import com.google.common.net.HttpHeaders;
import com.squareup.okhttp.Interceptor;
import com.squareup.okhttp.MediaType;
import com.squareup.okhttp.Request;
import com.squareup.okhttp.RequestBody;
import com.squareup.okhttp.Response;
import okio.BufferedSink;
import okio.GzipSink;
import okio.Okio;

import java.io.IOException;

/**
 * This {@link com.squareup.okhttp.Interceptor} compresses the HTTP request body with gzip.
 * 
 * Many web servers can't handle this but we know that the Telemetry API is able to do this.
 * 
 *
 * @see OkHttp Wiki
 */
public final class GzipRequestInterceptor implements Interceptor {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Request originalRequest = chain.request();
        if (originalRequest.body() == null || originalRequest.header(HttpHeaders.CONTENT_ENCODING) != null) {
            return chain.proceed(originalRequest);
        }

        Request compressedRequest = originalRequest.newBuilder()
                .header(HttpHeaders.CONTENT_ENCODING, "gzip")
                .method(originalRequest.method(), gzip(originalRequest.body()))
                .build();
        return chain.proceed(compressedRequest);
    }

    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();
            }
        };
    }
}