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Posted to cvs@httpd.apache.org by rb...@apache.org on 2002/03/02 17:15:29 UTC
cvs commit: httpd-2.0/docs/manual/mod mod_include.xml
rbowen 02/03/02 08:15:29
Added: docs/manual/mod mod_include.xml
Log:
Initial conversion. Need to clean this up a little.
Revision Changes Path
1.1 httpd-2.0/docs/manual/mod/mod_include.xml
Index: mod_include.xml
===================================================================
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="../style/manual.xsl"?>
<modulesynopsis>
<name>mod_include</name>
<status>Base</status>
<identifier>include_module</identifier>
<source>mod_include.c</source>
<compatibility></compatibility>
<description>This module provides for server-parsed html
documents.</description>
<summary>
<p>This module provides a filter which will process files
before they are sent to the client. The processing is
controlled by specially formated SGML comments, referred to as
<em>elements</em>. These elements allow conditional text, the
inclusion other files or programs, as well as the setting and
printing of environment variables.</p>
<seealso><strong>See also</strong>:
<directive module="core">Options</directive>,
<directive module="core">SetOutputFilter</directive>
and <directive module="core">AcceptPathInfo</directive>.</seealso>
</summary>
<section id="enabling">
<title>Enabling Server-Side Includes</title>
<p>Server Side Includes are implemented by the
<code>INCLUDES</code> <a href="../filter.html">filter</a>. If
documents containing server-side include directives are given
the extension .shtml, the following directives will make Apache
parse them and assign the resulting document the mime type of
<code>text/html</code>:</p>
<example>
AddType text/html .shtml<br />
AddOutputFilter INCLUDES .shtml
</example>
<p>The following directive must be given for the directories
containing the shtml files (typically in a
<code><Directory></code> section, but this directive is
also valid .htaccess files if <code>AllowOverride
Options</code> is set):</p>
<example>
Options +Includes
</example>
<p>For backwards compatibility, the <code>server-parsed</code>
<a href="../handler.html">handler</a> also activates the
INCLUDES filter. As well, Apache will activate the INCLUDES
filter for any document with mime type
<code>text/x-server-parsed-html</code> or
<code>text/x-server-parsed-html3</code> (and the resulting
output will have the mime type <code>text/html</code>).</p>
<p>For more information, see our <a
href="../howto/ssi.html">Tutorial on Server Side
Includes</a>.</p>
</section>
<section id="basic">
<title>Basic Elements</title>
<p>The document is parsed as an HTML document, with special
commands embedded as SGML comments. A command has the syntax: </p>
<example>
<code><!--#</code><em>element attribute=value
attribute=value ...</em> <code>--></code>
</example>
<p>The value will often be enclosed in double quotes; many
commands only allow a single attribute-value pair. Note that
the comment terminator (<samp>--></samp>) should be preceded
by whitespace to ensure that it isn't considered part of an SSI
token. </p>
<p>The allowed elements are:</p>
<dl>
<dt><strong>config</strong></dt>
<dd>
This command controls various aspects of the parsing. The
valid attributes are:
<dl>
<dt><strong>errmsg</strong></dt>
<dd>The value is a message that is sent back to the
client if an error occurs whilst parsing the
document.</dd>
<dt><strong>sizefmt</strong></dt>
<dd>The value sets the format to be used which displaying
the size of a file. Valid values are <code>bytes</code>
for a count in bytes, or <code>abbrev</code> for a count
in Kb or Mb as appropriate.</dd>
<dt><strong>timefmt</strong></dt>
<dd>The value is a string to be used by the
<code>strftime(3)</code> library routine when printing
dates.</dd>
</dl>
</dd>
<dt><strong><a id="echo" name="echo">echo</a></strong></dt>
<dd>
This command prints one of the <a href="#includevars">include
variables</a>, defined
below. If the variable is unset, it is printed as
<code>(none)</code>. Any dates printed are subject to the
currently configured <code>timefmt</code>. Attributes:
<dl>
<dt><strong>var</strong></dt>
<dd>The value is the name of the variable to print.</dd>
<dt><strong>encoding</strong></dt>
<dd>Specifies how Apache should encode special characters
contained in the variable before outputting them. If set
to "none", no encoding will be done. If set to "url",
then URL encoding (also known as %-encoding; this is
appropriate for use within URLs in links, etc.) will be
performed. At the start of an <code>echo</code> element,
the default is set to "entity", resulting in entity
encoding (which is appropriate in the context of a
block-level HTML element, eg. a paragraph of text). This
can be changed by adding an <code>encoding</code>
attribute, which will remain in effect until the next
<code>encoding</code> attribute is encountered or the
element ends, whichever comes first. Note that the
<code>encoding</code> attribute must <em>precede</em> the
corresponding <code>var</code> attribute to be effective,
and that only special characters as defined in the
ISO-8859-1 character encoding will be encoded. This
encoding process may not have the desired result if a
different character encoding is in use. Apache 1.3.12 and
above; previous versions do no encoding.</dd>
</dl>
</dd>
<dt><strong>exec</strong></dt>
<dd>
The exec command executes a given shell command or CGI
script. The IncludesNOEXEC <a
href="core.html#options">Option</a> disables this command
completely. The valid attributes are:
<dl>
<dt><strong>cgi</strong></dt>
<dd>
The value specifies a (%-encoded) URL relative path to
the CGI script. If the path does not begin with a (/),
then it is taken to be relative to the current
document. The document referenced by this path is
invoked as a CGI script, even if the server would not
normally recognize it as such. However, the directory
containing the script must be enabled for CGI scripts
(with <a
href="mod_alias.html#scriptalias">ScriptAlias</a> or
the ExecCGI <a href="core.html#options">Option</a>).
<p>The CGI script is given the PATH_INFO and query
string (QUERY_STRING) of the original request from the
client; these cannot be specified in the URL path. The
include variables will be available to the script in
addition to the standard <a href="mod_cgi.html">CGI</a>
environment.</p>
<p>For example:</p>
<code><!--#exec cgi="/cgi-bin/example.cgi" --></code>
<p>If the script returns a Location: header instead of
output, then this will be translated into an HTML
anchor.</p>
<p>The <code><a href="#includevirtual">include
virtual</a></code> element should be
used in preference to <code>exec cgi</code>. In particular,
if you need to pass additional arguments to a CGI program,
using the query string, this cannot be done with <code>exec
cgi</code>, but can be done with <code>include
virtual</code>, as shown here:</p>
<code><!--#include virtual="/cgi-bin/example.cgi?argument=value" --></code>
</dd>
<dt><strong>cmd</strong></dt>
<dd>
<p>The server will execute the given string using
<code>/bin/sh</code>. The <a
href="#includevars">include variables</a> are available
to the command, in addition to the usual set of CGI
variables.</p>
<p>The use of <code><a href="#includevirtual">#include
virtual</a></code> is almost always
prefered to using either <code>#exec cgi</code> or <code>#exec
cmd</code>. The former (<code>#include virtual</code>) used the
standard Apache sub-request mechanism to include files or
scripts. It is much better tested and maintained.</p>
<p>In addition, on some platforms, like Win32, and on unix
when using suexec, you cannot pass arguments to a command in
an <code>exec</code> directive, or otherwise include spaces in
the command. Thus, while the following will work under a
non-suexec configuration on unix, it will not produce the
desired result under Win32, or when running suexec:</p>
<code><!--#exec cmd="perl /path/to/perlscript arg1 arg2" --></code>
</dd>
</dl>
</dd>
<dt><strong>fsize</strong></dt>
<dd>
This command prints the size of the specified file, subject
to the <code>sizefmt</code> format specification.
Attributes:
<dl>
<dt><strong>file</strong></dt>
<dd>The value is a path relative to the directory
containing the current document being parsed.</dd>
<dt><strong>virtual</strong></dt>
<dd>The value is a (%-encoded) URL-path relative to the
current document being parsed. If it does not begin with
a slash (/) then it is taken to be relative to the
current document.</dd>
</dl>
</dd>
<dt><strong>flastmod</strong></dt>
<dd>This command prints the last modification date of the
specified file, subject to the <code>timefmt</code> format
specification. The attributes are the same as for the
<code>fsize</code> command.</dd>
<dt><strong>include</strong></dt>
<dd>
This command inserts the text of another document or file
into the parsed file. Any included file is subject to the
usual access control. If the directory containing the
parsed file has the <a href="core.html#options">Option</a>
IncludesNOEXEC set, and the including the document would
cause a program to be executed, then it will not be
included; this prevents the execution of CGI scripts.
Otherwise CGI scripts are invoked as normal using the
complete URL given in the command, including any query
string.
<p>An attribute defines the location of the document; the
inclusion is done for each attribute given to the include
command. The valid attributes are:</p>
<dl>
<dt><strong>file</strong></dt>
<dd>The value is a path relative to the directory
containing the current document being parsed. It cannot
contain <code>../</code>, nor can it be an absolute path.
Therefore, you cannot include files that are outside of the
document root, or above the current document in the directory
structure.
The <code>virtual</code> attribute should always be used
in preference to this one.</dd>
<dt><strong><a name="includevirtual">virtual</a></strong></dt>
<dd>
<p>The value is a (%-encoded) URL relative to the
current document being parsed. The URL cannot contain a
scheme or hostname, only a path and an optional query
string. If it does not begin with a slash (/) then it is
taken to be relative to the current document.</p>
<p>A URL is constructed from the attribute, and the output the
server would return if the URL were accessed by the client
is included in the parsed output. Thus included files can
be nested.</p>
<p>If the specified URL is a CGI program, the program will
be executed and its output inserted in place of the directive
in the parsed file. You may include a query string in a CGI
url:</p>
<code><!--#include virtual="/cgi-bin/example.cgi?argument=value" --></code>
<p><code>include virtual</code> should be used in preference
to <code>exec cgi</code> to include the output of CGI
programs into an HTML document.</p>
</dd>
</dl>
</dd>
<dt><strong>printenv</strong></dt>
<dd>
<p>This prints out a listing of all existing variables and
their values. Starting with Apache 1.3.12, special characters
are entity encoded (see the <a
href="#echo"><code>echo</code></a> element for details)
before being output. There are no attributes.</p>
<p>For example:</p>
<p><code><!--#printenv --></code></p>
<p>The <strong>printenv</strong> element is available only in
Apache 1.2 and above.</p>
</dd>
<dt><strong>set</strong></dt>
<dd>
This sets the value of a variable. Attributes:
<dl>
<dt><strong>var</strong></dt>
<dd>The name of the variable to set.</dd>
<dt><strong>value</strong></dt>
<dd>The value to give a variable.</dd>
</dl>
<p>
For example: <code><!--#set var="category" value="help"
--></code></p>
<p>The <strong>set</strong> element is available only in
Apache 1.2 and above.</p>
</dd>
</dl>
</section>
<section id="includevars">
<title>Include Variables</title>
In addition to the variables in the standard CGI environment,
these are available for the <code>echo</code> command, for
<code>if</code> and <code>elif</code>, and to any program
invoked by the document.
<dl>
<dt>DATE_GMT</dt>
<dd>The current date in Greenwich Mean Time.</dd>
<dt>DATE_LOCAL</dt>
<dd>The current date in the local time zone.</dd>
<dt>DOCUMENT_NAME</dt>
<dd>The filename (excluding directories) of the document
requested by the user.</dd>
<dt>DOCUMENT_URI</dt>
<dd>The (%-decoded) URL path of the document requested by the
user. Note that in the case of nested include files, this is
<em>not</em> then URL for the current document.</dd>
<dt>LAST_MODIFIED</dt>
<dd>The last modification date of the document requested by
the user.</dd>
</dl>
</section>
<section>
<title>Variable Substitution</title>
<p>Variable substitution is done within quoted strings in most
cases where they may reasonably occur as an argument to an SSI
directive. This includes the <samp>config</samp>,
<samp>exec</samp>, <samp>flastmod</samp>, <samp>fsize</samp>,
<samp>include</samp>, and <samp>set</samp> directives, as well
as the arguments to conditional operators. You can insert a
literal dollar sign into the string using backslash
quoting:</p>
<pre>
<!--#if expr="$a = \$test" -->
</pre>
<p>If a variable reference needs to be substituted in the
middle of a character sequence that might otherwise be
considered a valid identifier in its own right, it can be
disambiguated by enclosing the reference in braces,
<em>a la</em> shell substitution:</p>
<pre>
<!--#set var="Zed" value="${REMOTE_HOST}_${REQUEST_METHOD}" -->
</pre>
<p>This will result in the <samp>Zed</samp> variable being set
to "<samp>X_Y</samp>" if <samp>REMOTE_HOST</samp> is
"<samp>X</samp>" and <samp>REQUEST_METHOD</samp> is
"<samp>Y</samp>".</p>
<p>EXAMPLE: the below example will print "in foo" if the
DOCUMENT_URI is /foo/file.html, "in bar" if it is
/bar/file.html and "in neither" otherwise:</p>
<pre>
<!--#if expr="\"$DOCUMENT_URI\" = \"/foo/file.html\"" -->
in foo
<!--#elif expr="\"$DOCUMENT_URI\" = \"/bar/file.html\"" -->
in bar
<!--#else -->
in neither
<!--#endif -->
</pre>
</section>
<section>
<title id="flowctrl">Flow Control Elements</title>
These are available in Apache 1.2 and above. The basic flow
control elements are:
<pre>
<!--#if expr="<em>test_condition</em>" -->
<!--#elif expr="<em>test_condition</em>" -->
<!--#else -->
<!--#endif -->
</pre>
<p>The <strong><code>if</code></strong> element works like an
if statement in a programming language. The test condition is
evaluated and if the result is true, then the text until the
next <strong><code>elif</code></strong>,
<strong><code>else</code></strong>. or
<strong><code>endif</code></strong> element is included in the
output stream.</p>
<p>The <strong><code>elif</code></strong> or
<strong><code>else</code></strong> statements are be used the
put text into the output stream if the original test_condition
was false. These elements are optional.</p>
<p>The <strong><code>endif</code></strong> element ends the
<strong><code>if</code></strong> element and is required.</p>
<p><em>test_condition</em> is one of the following:</p>
<dl>
<dt><em>string</em></dt>
<dd>true if <em>string</em> is not empty</dd>
<dt><em>string1</em> = <em>string2</em><br />
<em>string1</em> != <em>string2</em><br />
<em>string1</em> < <em>string2</em><br />
<em>string1</em> <= <em>string2</em><br />
<em>string1</em> > <em>string2</em><br />
<em>string1</em> >= <em>string2</em></dt>
<dd>Compare string1 with string 2. If string2 has the form
<em>/string/</em> then it is compared as a regular
expression. Regular expressions have the same syntax as those
found in the Unix <samp>egrep</samp> command.</dd>
<dt>( <em>test_condition</em> )</dt>
<dd>true if <em>test_condition</em> is true</dd>
<dt>! <em>test_condition</em></dt>
<dd>true if <em>test_condition</em> is false</dd>
<dt><em>test_condition1</em> &&
<em>test_condition2</em></dt>
<dd>true if both <em>test_condition1</em> and
<em>test_condition2</em> are true</dd>
<dt><em>test_condition1</em> || <em>test_condition2</em></dt>
<dd>true if either <em>test_condition1</em> or
<em>test_condition2</em> is true</dd>
</dl>
<p>"<em>=</em>" and "<em>!=</em>" bind more tightly than
"<em>&&</em>" and "<em>||</em>". "<em>!</em>" binds
most tightly. Thus, the following are equivalent:</p>
<pre>
<!--#if expr="$a = test1 && $b = test2" -->
<!--#if expr="($a = test1) && ($b = test2)" -->
</pre>
<p>Anything that's not recognized as a variable or an operator
is treated as a string. Strings can also be quoted:
<em>'string'</em>. Unquoted strings can't contain whitespace
(blanks and tabs) because it is used to separate tokens such as
variables. If multiple strings are found in a row, they are
concatenated using blanks. So,</p>
<pre>
<em>string1 string2</em> results in <em>string1 string2</em>
<em>'string1 string2'</em> results in <em>string1 string2</em>
</pre>
</section>
<section>
<title>Using Server Side Includes for ErrorDocuments</title>
There is <a href="../misc/custom_errordocs.html">a document</a>
which describes how to use the features of mod_include to offer
internationalized customized server error documents.
<h2>PATH_INFO with Server Side Includes</h2>
<p>Files processed for server-side includes no longer accept
requests with PATH_INFO (trailing pathname information) by
default. You can use the <a
href="core.html#AcceptPathInfo">AcceptPathInfo</a> directive to
configure the server to accept requests with PATH_INFO.</p>
</section>
<directivesynopsis>
<name>SSIEndTag</name>
<description>Changes the string that mod_include looks for to end an
include command.</description>
<syntax>SSIEndTag <em>tag</em></syntax>
<default>SSIEndTag "-->"</default>
<contextlist><context>server config</context>
<context>virtual host</context></contextlist>
<override>FileInfo</override>
<compatibility>Apache 1.2 and Available in version 2.0.30 and later.
</compatibility>
<usage>
<p>This directive changes the string that mod_include looks for
to mark the end of a include command.</p>
<seealso>See also: <directive>SSIStartTag</directive>.</seealso>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>SSIErrorMsg</name>
<description>Changes the error message displayed when there is an error</description>
<syntax>SSIErrorMsg <em>message</em></syntax>
<default>SSIErrorMsg
"[an error occurred while processing this directive]"</default>
<contextlist>
<context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<override></override>
<compatibility>Available in version 2.0.30 and later.</compatibility>
<usage>
<p>The SSIErrorMsg directive changes the error message displayed
when mod_include encounters an error. For production servers you
may consider changing the default error message to
<code>"<-- Error -->"</code> so that the message
is not presented to the user.
</p>
<p>This directive has the same effect as the <code><--#config
errmsg=<em>message</em> --></code> element.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>SSIStartTag</name>
<description></description>
<syntax>Changes the string that mod_include looks for to start an
include element</syntax>
<default>SSIStartTag "<--!"</default>
<contextlist>
<context>server config</context>
<context>virtual host</context>
</contextlist>
<override></override>
<compatibility>Available in version 2.0.30 and later.</compatibility>
<usage>
<p>This directive changes the string that mod_include looks for
to mark an include element to process.</p>
<p>You may want to use this option if have 2 servers parsing the
output of a file each processing different commands (possibly at
different times).</p>
<seealso>See also: <directive>SSIEndTag</directive></seealso>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>SSITimeFormat</name>
<description>Configures the format in which date strings are
displayed</description>
<syntax>SSITimeFormat <em>formatstring</em></syntax>
<default>SSITimeFormat "%A, %d-%b-%Y %H:%M:%S %Z"</default>
<contextlist>
<context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<override></override>
<compatibility>Available in version 2.0.30 and later.</compatibility>
<usage>
<p>This directive changes the format in which date strings are displayed
when echoing DATE environment variables. The <em>formatstring</em>
is as in strftime(3) from the C standard library.</p>
<p>This directive has the same effect as the <code><--#config
timefmt=<em>formatstring</em> --></code> element.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>XBitHack</name>
<syntax>XBitHack on|off|full</syntax>
<default>XBitHack off</default>
<contextlist>
<context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<override>Options</override>
<compatibility></compatibility>
<description>Parse SSI directives in files with the execute
bit set</description>
<usage>
<p>The XBitHack directives controls the parsing of ordinary
html documents. This directive only affects files associated
with the MIME type <code>text/html</code>. XBitHack can take on
the following values:</p>
<dl>
<dt>off</dt>
<dd>No special treatment of executable files.</dd>
<dt>on</dt>
<dd>Any text/html file that has the user-execute bit set will
be treated as a server-parsed html document.</dd>
<dt>full</dt>
<dd>
As for <code>on</code> but also test the group-execute bit.
If it is set, then set the Last-modified date of the
returned file to be the last modified time of the file. If
it is not set, then no last-modified date is sent. Setting
this bit allows clients and proxies to cache the result of
the request.
<p><strong>Note:</strong> you would not want to use the full
option, unless you assure the group-execute bit is unset for
every SSI script which might <code>#include</code> a CGI
or otherwise produces different output on each hit (or could
potentially change on subsequent requests).</p>
</dd>
</dl>
</usage>
</directivesynopsis>
</modulesynopsis>