Question

Quick question: One can set the path where a cookie is valid, but is it also possible to get (read) this path from the cookie (in PHP)?

Or else: is it possible to extend a cookie’s time, without knowing what path it’s on (but keeping the path the same)?

Answer 1

Since most browsers still use Netscape’s specification (see cached version of http://wp.netscape.com/newsref/std/cookie_spec.html) and not the one specified in RFC 2109 or RFC 2965, the list elements in the Cookie request header field will only consist of the name and value pair:

When requesting a URL from an HTTP server, the browser will match the URL against all cookies and if any of them match, a line containing the name/value pairs of all matching cookies will be included in the HTTP request. Here is the format of that line:

Cookie: NAME1=OPAQUE_STRING1; NAME2=OPAQUE_STRING2 ...

Only the newer specifications (RFC 2109 and RFC 2965) allow the client to send the path within the request (excerpt from RFC 2109):

The syntax for the header is:

cookie          =       "Cookie:" cookie-version
                        1*((";" | ",") cookie-value)
cookie-value    =       NAME "=" VALUE [";" path] [";" domain]
cookie-version  =       "$Version" "=" value
NAME            =       attr
VALUE           =       value
path            =       "$Path" "=" value
domain          =       "$Domain" "=" value

[…] The value for
the path attribute must be the value from the Path attribute, if any,
of the corresponding Set-Cookie response header. Otherwise the
attribute should be omitted from the Cookie request header. […]