> Apache2.2 中文手册 > mod_include

Apache模块 mod_include

说明 实现服务端包含文档(SSI)处理
状态 基本(B)
模块名 include_module
源文件 mod_include.c
兼容性 Implemented as an output filter since Apache 2.0


This module provides a filter which will process files before they are sent to the client. The processing is controlled by specially formatted SGML comments, referred to as elements. These elements allow conditional text, the inclusion of other files or programs, as well as the setting and printing of environment variables.


filter. 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 text/html:

AddType text/html .shtml
AddOutputFilter INCLUDES .shtml

The following directive must be given for the directories containing the shtml files (typically in a <Directory> section, but this directive is also valid in .htaccess files if AllowOverride Options is set):

Options +Includes

For backwards compatibility, the server-parsed 处理器 also activates the INCLUDES filter. As well, Apache will activate the INCLUDES filter for any document with mime type text/x-server-parsed-htmltext/x-server-parsed-html3 (and the resulting output will have the mime type text/html).

For more information, see our Tutorial on Server Side Includes.


AcceptPathInfo directive to configure the server to accept requests with PATH_INFO.


config configure output formats echo print variables exec execute external programs fsize print size of a file flastmod print last modification time of a file include include a file printenv print all available variables set set a value of a variable

SSI elements may be defined by modules other than mod_include. In fact, the exec element is provided by mod_cgi, and will only be available if this module is loaded.

The config Element

This command controls various aspects of the parsing. The valid attributes are:

echomsg (Apache 2.1 and later)
The value is a message that is sent back to the client if the echo element attempts to echo an undefined variable. This overrides any SSIUndefinedEcho directives.
The value is a message that is sent back to the client if an error occurs while parsing the document. This overrides any SSIErrorMsg directives.
The value sets the format to be used which displaying the size of a file. Valid values are bytes for a count in bytes, or abbrev for a count in Kb or Mb as appropriate, for example a size of 1024 bytes will be printed as "1K".
The value is a string to be used by the strftime(3) library routine when printing dates.

include variables, defined below. If the variable is unset, the result is determined by the SSIUndefinedEcho directive. Any dates printed are subject to the currently configured timefmt.


The value is the name of the variable to print.

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 echo element, the default is set to entity, resulting in entity encoding (which is appropriate in the context of a block-level HTML element, 例如, a paragraph of text). This can be changed by adding an encoding attribute, which will remain in effect until the next encoding attribute is encountered or the element ends, whichever comes first.

encoding attribute must precede the corresponding var attribute to be effective, and 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.

In order to avoid cross-site scripting issues, you should always encode user supplied data.

The exec Element

exec command executes a given shell command or CGI script. It requires mod_cgi to be present in the server. If Options IncludesNOEXEC is set, this command is completely disabled. The valid attributes are:


The value specifies a (%-encoded) URL-path to the CGI script. If the path does not begin with a slash (/), 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 ScriptAliasOptions ExecCGI).

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 CGI environment.


<!--#exec cgi="/cgi-bin/example.cgi" -->

If the script returns a Location: header instead of output, then this will be translated into an HTML anchor.

include virtual element should be used in preference to exec cgi. In particular, if you need to pass additional arguments to a CGI program, using the query string, this cannot be done with exec cgi, but can be done with include virtual, as shown here:

<!--#include virtual="/cgi-bin/example.cgi?argument=value" -->


The server will execute the given string using /bin/sh. The include variables are available to the command, in addition to the usual set of CGI variables.

The use of #include virtual is almost always prefered to using either #exec cgi#exec cmd. The former (#include virtual) uses the standard Apache sub-request mechanism to include files or scripts. It is much better tested and maintained.

In addition, on some platforms, like Win32, and on unix when using suexec, you cannot pass arguments to a command in an exec 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:

<!--#exec cmd="perl /path/to/perlscript arg1 arg2" -->

The fsize Element

This command prints the size of the specified file, subject to the sizefmt format specification. Attributes:

The value is a path relative to the directory containing the current document being parsed.
The value is a (%-encoded) URL-path. If it does not begin with a slash (/) then it is taken to be relative to the current document. Note, that this does not print the size of any CGI output, but the size of the CGI script itself.

The flastmod Element

This command prints the last modification date of the specified file, subject to the timefmt format specification. The attributes are the same as for the fsize command.

Options IncludesNOEXEC set, then only documents with a text MIME-type (text/plain, text/html etc.) will be included. Otherwise CGI scripts are invoked as normal using the complete URL given in the command, including any query string.

An attribute defines the location of the document; the inclusion is done for each attribute given to the include command. The valid attributes are:

The value is a path relative to the directory containing the current document being parsed. It cannot contain ../, 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 virtual attribute should always be used in preference to this one.

The value is a (%-encoded) URL-path. 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.

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.

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:

<!--#include virtual="/cgi-bin/example.cgi?argument=value" -->

include virtual should be used in preference to exec cgi to include the output of CGI programs into an HTML document.

The printenv Element

This prints out a listing of all existing variables and their values. Special characters are entity encoded (see the echo element for details) before being output. There are no attributes.


<!--#printenv -->

The set Element

This sets the value of a variable. Attributes:

The name of the variable to set.
The value to give a variable.


<!--#set var="category" value="help" -->


Include Variables

In addition to the variables in the standard CGI environment, these are available for the echo command, for ifelif, and to any program invoked by the document.

The current date in Greenwich Mean Time.
The current date in the local time zone.
The filename (excluding directories) of the document requested by the user.
The (%-decoded) URL path of the document requested by the user. Note that in the case of nested include files, this is not the URL for the current document.
The last modification date of the document requested by the user.
If a query string is present, this variable contains the (%-decoded) query string, which is escaped for shell usage (special characters like & etc. are preceded by backslashes).

Variable Substitution

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 config, exec, flastmod, fsize, include, echo, and set directives, as well as the arguments to conditional operators. You can insert a literal dollar sign into the string using backslash quoting:

<!--#if expr="$a = \$test" -->

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, a la shell substitution:

<!--#set var="Zed" value="${REMOTE_HOST}_${REQUEST_METHOD}" -->

This will result in the Zed variable being set to "X_Y" if REMOTE_HOST is "X" and REQUEST_METHOD is "Y".

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:

<!--#if expr='"$DOCUMENT_URI" = "/foo/file.html"' -->
in foo
<!--#elif expr='"$DOCUMENT_URI" = "/bar/file.html"' -->
in bar
<!--#else -->
in neither
<!--#endif -->


PCRE engine and have the same syntax as those in perl 5. Note that == is just an alias for = and behaves exactly the same way.

If you are matching positive (===), you can capture grouped parts of the regular expression. The captured parts are stored in the special variables $1 .. $9.


<!--#if expr="$QUERY_STRING = /^sid=([a-zA-Z0-9]+)/" -->
<!--#set var="session" value="$1" -->
<!--#endif -->

string1 < string2
string1 <= string2
string1 > string2
string1 >= string2
Compare string1 with string2. Note, that strings are compared literally (using strcmp(3)). Therefore the string "100" is less than "20".
( test_condition )
true if test_condition is true
! test_condition
true if test_condition is false
test_condition1 && test_condition2
true if both test_condition1test_condition2 are true
test_condition1 || test_condition2
true if either test_condition1test_condition2 is true

"=" and "!=" bind more tightly than "&&" and "||". "!" binds most tightly. Thus, the following are equivalent:

<!--#if expr="$a = test1 && $b = test2" -->
<!--#if expr="($a = test1) && ($b = test2)" -->

The boolean operators &&|| share the same priority. So if you want to bind such an operator more tightly, you should use parentheses.

Anything that's not recognized as a variable or an operator is treated as a string. Strings can also be quoted: 'string'. 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,

string1    string2 results in string1 string2

'string1    string2' results in string1    string2.

Optimization of Boolean Expressions

If the expressions become more complex and slow down processing significantly, you can try to optimize them according to the evaluation rules:

  • Expressions are evaluated from left to right
  • Binary boolean operators (&&||) are short circuited wherever possible. In conclusion with the rule above that means, mod_include evaluates at first the left expression. If the left result is sufficient to determine the end result, processing stops here. Otherwise it evaluates the right side and computes the end result from both left and right results.
  • Short circuit evaluation is turned off as long as there are regular expressions to deal with. These must be evaluated to fill in the backreference variables ($1 .. $9).

If you want to look how a particular expression is handled, you can recompile mod_include using the -DDEBUG_INCLUDE compiler option. This inserts for every parsed expression tokenizer information, the parse tree and how it is evaluated into the output sent to the client.


说明 String that ends an include element 语法 SSIEndTag tag 默认值 SSIEndTag "-->" 作用域 server config, virtual host 状态 基本(B) 模块 mod_include 兼容性 仅在 Apache 2.0.30 及以后的版本中可用

This directive changes the string that mod_include looks for to mark the end of an include element.


SSIEndTag "%>"


  • SSIStartTag

说明 Error message displayed when there is an SSI error 语法 SSIErrorMsg message 默认值 SSIErrorMsg "[an error occurred while processing this directive]" 作用域 server config, virtual host, directory, .htaccess 覆盖项 All 状态 基本(B) 模块 mod_include 兼容性 仅在 Apache 2.0.30 及以后的版本中可用

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 "<!-- Error -->" so that the message is not presented to the user.

This directive has the same effect as the <!--#config errmsg=message --> element.


SSIErrorMsg "<!-- Error -->"


说明 String that starts an include element 语法 SSIStartTag tag 默认值 SSIStartTag "<!--#" 作用域 server config, virtual host 状态 基本(B) 模块 mod_include 兼容性 仅在 Apache 2.0.30 及以后的版本中可用

This directive changes the string that mod_include looks for to mark an include element to process.

You may want to use this option if you have 2 servers parsing the output of a file each processing different commands (possibly at different times).


SSIStartTag "<%"
SSIEndTag "%>"

The example given above, which also specifies a matching SSIEndTag, will allow you to use SSI directives as shown in the example below:

SSI directives with alternate start and end tags

<%printenv %>


  • SSIEndTag

说明 Configures the format in which date strings are displayed 语法 SSITimeFormat formatstring 默认值 SSITimeFormat "%A, %d-%b-%Y %H:%M:%S %Z" 作用域 server config, virtual host, directory, .htaccess 覆盖项 All 状态 基本(B) 模块 mod_include 兼容性 仅在 Apache 2.0.30 及以后的版本中可用

This directive changes the format in which date strings are displayed when echoing DATE environment variables. The formatstring is as in strftime(3) from the C standard library.

This directive has the same effect as the <!--#config timefmt=formatstring --> element.


SSITimeFormat "%R, %B %d, %Y"

The above directive would cause times to be displayed in the format "22:26, June 14, 2002".


说明 String displayed when an unset variable is echoed 语法 SSIUndefinedEcho string 默认值 SSIUndefinedEcho "(none)" 作用域 server config, virtual host, directory, .htaccess 覆盖项 All 状态 基本(B) 模块 mod_include 兼容性 仅在 Apache 2.0.34 及以后的版本中可用

This directive changes the string that mod_include displays when a variable is not set and "echoed".


SSIUndefinedEcho "<!-- undef -->"


说明 Parse SSI directives in files with the execute bit set 语法 XBitHack on|off|full 默认值 XBitHack off 作用域 server config, virtual host, directory, .htaccess 覆盖项 Options 状态 基本(B) 模块 mod_include

XBitHack directive controls the parsing of ordinary html documents. This directive only affects files associated with the MIME-type text/html. XBitHack can take on the following values:

No special treatment of executable files.
Any text/html file that has the user-execute bit set will be treated as a server-parsed html document.
As for on 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.


You would not want to use the full option, unless you assure the group-execute bit is unset for every SSI script which might #include a CGI or otherwise produces different output on each hit (or could potentially change on subsequent requests).