Commit 804771db authored by Graham Leggett's avatar Graham Leggett
Browse files

Updated mod_headers documentation to coincide with addition of RequestHeader 

directive.
PR:
Obtained from:
Reviewed by:


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89181 13f79535-47bb-0310-9956-ffa450edef68
parent ffc72f7a

docs/manual/mod/mod_headers.html

+109 −12
Original line number Diff line number Diff line
@@ -36,21 +36,117 @@ REL="Help" 
<A

HREF="module-dict.html#Compatibility"

REL="Help"

><STRONG>Compatibility:</STRONG></A> Available in Apache 1.2 and later.

><STRONG>Compatibility:</STRONG></A> Available in Apache 1.2 and later. In

Apache 2.0 the Header directive was replaced with Header.

</P>



<h2>Summary</h2>



This module provides a directive to control the sending of HTTP

headers.  Headers can be merged, replaced or removed. 

This module provides directives to control and modify HTTP

request and response headers.  Headers can be merged,

replaced or removed.



<H2>Directives</H2>

<UL>

<LI><A HREF="#header">RequestHeader</A>

<LI><A HREF="#header">Header</A>

</UL>



<HR>



<H2><A NAME="header">RequestHeader</A> directive</H2>

<A

 HREF="directive-dict.html#Syntax"

 REL="Help"

><STRONG>Syntax:</STRONG></A> RequestHeader set|append|add

 <EM>header</EM> <EM>value</EM><BR>

<A

 HREF="directive-dict.html#Syntax"

 REL="Help"

><STRONG>Syntax:</STRONG></A> RequestHeader unset <EM>header</EM><BR>

<A

 HREF="directive-dict.html#Context"

 REL="Help"

><STRONG>Context:</STRONG></A> server config, virtual host, access.conf,

 .htaccess<BR>

<A

 HREF="directive-dict.html#Override"

 REL="Help"

><STRONG>Override:</STRONG></A> FileInfo<BR>

<A

 HREF="directive-dict.html#Status"

 REL="Help"

><STRONG>Status:</STRONG></A> Extension<BR>

<A

 HREF="directive-dict.html#Module"

 REL="Help"

><STRONG>Module:</STRONG></A> mod_header<P>



This directive can replace, merge or remove HTTP request headers. The header

is modified just before the content handler is run, allowing incoming 

headers to be modified. The action it performs is determined by the first 

argument. This can be one of the following values:



<UL>

<LI><STRONG>set</STRONG><BR>

  The request header is set, replacing any previous header with this name



<LI><STRONG>append</STRONG><BR>

  The request header is appended to any existing header of the same

  name. When a new value is merged onto an existing header it is

  separated from the existing header with a comma. This is the HTTP standard

  way of giving a header multiple values.



<LI><STRONG>add</STRONG><BR>

  The request header is added to the existing set of headers, even if

  this header already exists. This can result in two (or more) headers

  having the same name. This can lead to unforeseen consequences, and in

  general "append" should be used instead.



<LI><STRONG>unset</STRONG><BR>

  The request header of this name is removed, if it exists. If there are

  multiple headers of the same name, all will be removed.

</UL>



This argument is followed by a header name, which can include the

final colon, but it is not required. Case is ignored. For

add, append and set a value is given as the third argument. If this

value contains spaces, it should be surrounded by double quotes.

For unset, no value should be given.



<H3>Order of Processing</H3>



The RequestHeader (and Header) directives can occur almost anywhere within 

the server configuration. It is valid in the main server config and virtual 

host sections, inside &lt;Directory&gt;, &lt;Location&gt; and &lt;Files&gt;

sections, and within .htaccess files.

<P>

The RequestHeader directives are processed in the following order:

<OL>

<LI>main server

<LI>virtual host

<LI>&lt;Directory&gt; sections and .htaccess

<LI>&lt;Location&gt;

<LI>&lt;Files&gt;

</OL>



Order is important. These two headers have a different effect if reversed:

<PRE>

RequestHeader append MirrorID "mirror 12"

RequestHeader unset MirrorID

</PRE>



This way round, the MirrorID header is not set. If reversed, the MirrorID

header is set to "mirror 12".

<P>



The RequestHeader directive is processed just before the request is run

by its handler in the fixup phase. This should allow headers generated by

the browser, or by Apache input filters to be overridden or modified. 

<P>



<HR>



<H2><A NAME="header">Header</A> directive</H2>

<A

 HREF="directive-dict.html#Syntax"
@@ -79,9 +175,11 @@ headers. Headers can be merged, replaced or removed. 
 REL="Help"

><STRONG>Module:</STRONG></A> mod_header<P>



This directive can replace, merge or remove HTTP response headers. The

action it performs is determined by the first argument. This can be one

of the following values:

This directive can replace, merge or remove HTTP response headers. The header

is modified just after the content handler and output filters are run, 

allowing outgoing headers to be modified. The action it performs is determined 

by the first argument. This can be one of the following values, as with

RequestHeader:



<UL>

<LI><STRONG>set</STRONG><BR>
@@ -112,9 +210,9 @@ For unset, no value should be given. 


<H3>Order of Processing</H3>



The Header directive can occur almost anywhere within the server

configuration. It is valid in the main server config and virtual host

sections, inside &lt;Directory&gt;, &lt;Location&gt; and &lt;Files&gt;

The Header (like the RequestHeader) directives can occur almost anywhere within 

the server configuration. It is valid in the main server config and virtual 

host sections, inside &lt;Directory&gt;, &lt;Location&gt; and &lt;Files&gt;

sections, and within .htaccess files.

<P>

The Header directives are processed in the following order:
@@ -137,9 +235,8 @@ header is set to "John P. Doe". 
<P>



The Header directives are processed just before the response is sent

by its handler. These means that some headers that are added just

before the response is sent cannot be unset or overridden. This

includes headers such as "Date" and "Server".

to the network. These means that it is possible to set and/or override

most headers, except for those headers added by the header filter.

<P>



<!--#include virtual="footer.html" -->