thomascorthals commented on pull request #495: URL: https://github.com/apache/solr/pull/495#issuecomment-1005223884
I'm afraid setting `Content-Length: 0` is incorrect for a `HEAD` request. https://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html#sec9.4 (emphasis mine) > The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the **HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request**. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. This method is often used for testing hypertext links for validity, accessibility, and recent modification. > > The response to a HEAD request MAY be cacheable in the sense that the information contained in the response MAY be used to update a previously cached entity from that resource. If the new field values indicate that the cached entity differs from the current entity (as would be indicated by a change in Content-Length, Content-MD5, ETag or Last-Modified), then the cache MUST treat the cache entry as stale. The [MDN Web Docs](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods/HEAD) even use this as an explicit example. > For example, if a URL might produce a large download, a `HEAD` request could read its `Content-Length` header to check the filesize without actually downloading the file. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
