InterceptingClientHttpRequest is always buffered despite the delegate [SPR-16380]

[spring-projects-issues]

Wyatt Smith opened SPR-16380 and commented

When writing an application, I had to upload a large file (~600 MB) using the RestTemplate, as well as use an oAuth2 bearer header. To do this, I added a custom interceptor to write the oauth header:

restTemplate.getInterceptors().add(new OauthAuthorizationInterceptor(accessToken));

Because the file is so large, I was getting an OutOfMemoryException, so I disabled buffering:

HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
requestFactory.setBufferRequestBody(false);
restTemplate = new RestTemplate(requestFactory);

The application continued getting the memory exception. Upon investigation, it appears as though the ClientHttpRequestFactory is wrapped by an InterceptingClientHttpRequestFactory because of the interceptor (InterceptingHttpAccessor#getRequestFactory). InterceptingClientHttpRequestFactory.getRequestFactory() returns a InterceptingClientHttpRequest, which is a AbstractBufferingClientHttpRequest (InterceptingClientHttpRequestFactory#createRequest). Despite requestFactory.setBufferRequestBody(false), a buffered request is made.

My temporary solution is to manually add the Authorization header everywhere and eliminate the interceptor so InterceptingHttpAccessor#getRequestFactory returns my original HttpComponentsClientHttpRequestFactory with buffering disabled instead of a InterceptingClientHttpRequestFactory wrapping it.

The long term solution should be for the InterceptingClientHttpRequestFactory to be allowed to be streaming instead of buffered.

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Affects: 4.3.9

Issue Links:

• HttpComponentsStreamingClientHttpRequest fails if restTemplate has interceptors [SPR-17113] #21650 HttpComponentsStreamingClientHttpRequest fails if restTemplate has interceptors

[spring-projects-issues]

Rossen Stoyanchev commented

As per the answer to the similar request #21650, we're not going to support this, now that the WebClient is available and provides first-class support for streaming.