HEAD requests the headers that would be returned if the
HEAD request's URL was instead requested with the HTTP
GET method. 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.
A response to a
HEAD method should not have a body. If it has one anyway, that body must be ignored: any entity headers that might describe the erroneous body are instead assumed to describe the response which a similar
GET request would have received.
If the response to a
HEAD request shows that a cached URL response is now outdated, the cached copy is invalidated even if no
GET request was made.
|Request has body||No|
|Successful response has body||No|
|Allowed in HTML forms||No|
|RFC 7231, section 4.3.2: HEAD||Hypertext Transfer Protocol (HTTP/1.1): Semantics and Content|
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