LegacyRedirectInterceptor.java

import java.io.IOException;
import okhttp3.Interceptor;
import okhttp3.Response;

import static okhttp3.internal.http.StatusLine.HTTP_PERM_REDIRECT;
import static okhttp3.internal.http.StatusLine.HTTP_TEMP_REDIRECT;

/**
 * In OkHttp 4.5 and earlier, HTTP 307 and 308 redirects were only honored if the request method
 * was GET or HEAD.
 *
 * In OkHttp 4.6 and later, HTTP 307 and 308 redirects are honored for all request methods.
 *
 * If you're upgrading to OkHttp 4.6 and would like to retain the previous behavior, install this
 * as a **network interceptor**. It will strip the `Location` header of impacted responses to
 * prevent the redirect.
 *
 * <pre>{@code
 *
 *    OkHttpClient client = client.newBuilder()
 *        .addNetworkInterceptor(new LegacyRedirectInterceptor())
 *        .build();
 *
 * }</pre>
 */
class LegacyRedirectInterceptor implements Interceptor {
  @Override public Response intercept(Chain chain) throws IOException {
    Response response = chain.proceed(chain.request());

    int code = response.code();
    if (code != HTTP_TEMP_REDIRECT && code != HTTP_PERM_REDIRECT) return response;

    String method = response.request().method();
    if (method.equals("GET") || method.equals("HEAD")) return response;

    String location = response.header("Location");
    if (location == null) return response;

    return response.newBuilder()
        .removeHeader("Location")
        .header("LegacyRedirectInterceptor-Location", location)
        .build();
  }
}