From ec51a15b114d28d2ca87b0059f72ca92d2b97ab8 Mon Sep 17 00:00:00 2001
From: "Roy T. Fielding"
+ This module is contained in the
+ This module controls the setting of the
+ The
+
+ Syntax: ExpiresActive boolean
+
+ This directive enables or disables the generation of the
+
+ Note that this directive does not guarantee that an
+
+ Syntax: ExpiresByType mime-type <code>seconds
+
+ This directive defines the value of the
+ The base time is either the last modification time of the file, or the
+ time of the client's access to the document. Which should be used is
+ specified by the
+ The difference in effect is subtle. If M is used, all current
+ copies of the document in all caches will expire at the same time,
+ which can be good for something like a weekly notice that's always
+ found at the same URL. If A is used, the date of expiration
+ is different for each client; this can be good for image files that
+ don't change very often, particularly for a set of related documents
+ that all refer to the same images (i.e., the images will be
+ accessed repeatedly within a relatively short timespan).
+
+ Example:
+
+ Module mod_expires
+ mod_expires.c
file, and
+ is not compiled in by default. It provides for the
+ generation of Expires
headers according to user-specified
+ criteria.
+ Summary
+ Expires
HTTP
+ header in server responses. The expiration date can set to be
+ relative to either the time the source file was last modified, or to
+ the time of the client access.
+ Expires
HTTP header is an instruction to the client
+ about the document's validity and persistence. If cached, the document
+ may be fetched from the cache rather than from the source until this
+ time has passed. After that, the cache copy is considered
+ "expired" and invalid, and a new copy must be obtained from
+ the source.
+ Directives
+
+
+ ExpiresActive directive
+
+
+
+ Context: server config, virtual host, directory, .htaccess
+
+ Override: Indexes
+
+ Status: Extension
+
+ Module: mod_expires
+ Expires
header for the document realm in question. (That
+ is, if found in an .htaccess
file, for instance, it
+ applies only to documents generated from that directory.) If set to
+ Off
, no Expires
header will be
+ generated for any document in the realm (unless overridden at a lower
+ level, such as an .htaccess
file overriding a server
+ config file). If set to On
, the header will be
+ added to served documents according to the criteria defined by the
+ ExpiresByType
+ and
+ ExpiresDefault
+ directives (q.v.).
+ Expires
header will be generated. If the criteria aren't
+ met, no header will be sent, and the effect will be as though this
+ directive wasn't even specified.
+
+
+ ExpiresByType directive
+
+
+
+ Context: server config, virtual host, directory, .htaccess
+
+ Override: Indexes
+
+ Status: Extension
+
+ Module: mod_expires
+ Expires
header
+ generated for documents of the specified type (e.g.,
+ text/html
). The second argument sets the number of
+ seconds that will be added to a base time to construct the expiration
+ date.
+ <code>
field;
+ M means that the file's last modification time should
+ be used as the base time, and A means the client's
+ access time should be used.
+
+ ExpiresActive On # enable expirations
+ ExpiresByType image/gif A2592000 # expire GIF images after a month
+ # in the client's cache
+ ExpiresByType text/html M604800 # HTML documents are good for a
+ # week from the time they were
+ # changed, period
+
+
+ Note that this directive only has effect if ExpiresActive
+ On
has been specified. It overrides, for the specified MIME
+ type only, any expiration date set by the
+ ExpiresDefault
+ directive.
+
+ Syntax: ExpiresDefault <code>seconds
+
+ Context: server config, virtual host, directory, .htaccess
+
+ Override: Indexes
+
+ Status: Extension
+
+ Module: mod_expires
+
+ This directive sets the default algorithm for calculating the + expiration time for all documents in the affected realm. It can be + overridden on a type-by-type basis by the + ExpiresByType + directive. See the description of that directive for details about + the syntax of the argument. +
+ + + -- 2.40.0