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JavaScript Express Basics (2015) The Request and Response Objects in Express Responses and the Response Object

Nikolay Komolov
Nikolay Komolov
23,033 Points
Posted by Nikolay Komolov
Nikolay Komolov
23,033 Points

Get status code 304 on response

When visiting the '/blog' route, I get the status code 304 instead of 200.

What can be the reason? Thanks!

1 Answer

Jaro Schwab
Jaro Schwab
8,957 Points

The status Code 304 is not a problem. It simply means that your response is not modified and your browser turns to cache to fetch the resource.

Definition from https://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html:

"If the client has performed a conditional GET request and access is allowed, but the document has not been modified, the server SHOULD respond with this status code. The 304 response MUST NOT contain a message-body, and thus is always terminated by the first empty line after the header fields.

The response MUST include the following header fields:

Date, unless its omission is required by section 14.18.1 If a clockless origin server obeys these rules, and proxies and clients add their own Date to any response received without one (as already specified by [RFC 2068], section 14.19), caches will operate correctly.

ETag and/or Content-Location, if the header would have been sent in a 200 response to the same request Expires, Cache-Control, and/or Vary, if the field-value might differ from that sent in any previous response for the same variant If the conditional GET used a strong cache validator (see section 13.3.3), the response SHOULD NOT include other entity-headers. Otherwise (i.e., the conditional GET used a weak validator), the response MUST NOT include other entity-headers; this prevents inconsistencies between cached entity-bodies and updated headers.

If a 304 response indicates an entity not currently cached, then the cache MUST disregard the response and repeat the request without the conditional.

If a cache uses a received 304 response to update a cache entry, the cache MUST update the entry to reflect any new field values given in the response."