HTTP Request and Response Headers

These flashcards cover key concepts related to HTTP request and response headers.

What does the Accept header indicate in an HTTP request?

It indicates which content types the client can process (e.g., text/html, application/json).

What is the purpose of the Accept-Language header?

It lists the client’s preferred languages, from most to least preferred (e.g., en-US,en;q=0.8).

What does the Accept-Encoding header specify?

It specifies which content encodings (usually compression formats like gzip, br) are supported by the client.

What is the function of the Cookie header?

It sends stored cookies back to the server; used to maintain sessions and preferences.

What does the Host header indicate?

It specifies the target host (domain name and optional port) and is mandatory in HTTP/1.1 requests.

What does the If-Modified-Since header contain?

It contains the last modification date of a cached resource, which the server uses to validate the cached version.

What is the purpose of the If-None-Match header in an HTTP request?

It sends the ETag previously received for a resource to detect changes in the resource.

What information does the Referer header provide?

It identifies the URL of the page that originated the current request.

What does the User-Agent header describe?

It describes the client software making the request (browser name, version, OS, etc.).

What does the Cache-Control header provide in an HTTP response?

It provides caching instructions for the client and intermediate proxies (e.g., no-cache, max-age=3600).

What is an ETag in the context of HTTP responses?

A unique identifier (hash) that represents the current version of the resource, used for cache validation.

What does the Expires header specify?

It specifies the exact date/time when the resource should be considered stale (used for caching).

What does the Vary header list?

It lists which request headers might cause a variation in the response content (e.g., Accept-Language).

What does the Location header indicate in an HTTP response?

It indicates the new URL to request when the response is a redirection (e.g., status code 301 or 302).

What information does the Server header provide?

It identifies the software used by the origin server (e.g., Apache/2.4.58).

What is the purpose of the Set-Cookie header?

It sends cookies to the client; these will be stored and returned in future requests.