About SSI
SSI Commands
The INCLUDE Command
The ECHO Command
The EXEC Command
The FSIZE Command
The FLASTMOD Command
The CONFIG Command
ABOUT SERVER SIDE INCLUDESA
server side include, or SSI, is a piece of code that is embedded into an HTML page and
interpreted by the the server before the page is sent to the client's browser. SSI's allow
you to include information in your HTML files like a file's date of last modification,
another HTML file, a counter, or the output of any CGI script.
Server Side Includes are server intensive. Because
all files need to be parsed by the server, having all of your pages SSI would cut
performance.
Any file that has the extension .shtml will
automatically be parsed by the server. You can use index.shtml instead of index.html
as your default directory file.
SSI COMMANDS
SSI Commands The following is a list of Server Side
Include basics: A server side include command is contained within a comment tag:
<!--#command argument="value"
-->
Syntax must be correct, or your include will not work.
The INCLUDE Command
To include the contents of another file in a shtml
file, you use the include command.
The include command has two possible arguments: virtual
and file.
"Virtual" is used when the path to the
document is given relative to the document root (usually your www directory.)
"File" is used when the path to the
document is given relative to the shtml file itself. However, you cannot use
"file" to go up a directory ( "../slime.html" won't work.)
Say we want to include the file named
"file.html" which resides in the same sub directory of as this shtml file.
- To include it using "virtual," you
would use:
- <!--#include
virtual="/mirror/ssi/file.html" -->
This would return: This is from file.html
- To include it using "file," you would
use:
- <!--#include file="file.html" -->
This would return: This is from file.html
The ECHO Command
The echo command includes, or "echoes,"
the contents of an environment variable. Here are some examples showing the SSI tag and
the results :
- <!--#echo var="DOCUMENT_NAME" -->
- This document is named: man7.htm
- <!--#echo var="DATE_LOCAL" -->
- You accessed this document: Tuesday, 03-Jan-98
14:02:35 EDT
- <!--#echo var="DATE_GMT" -->
- This is the same as the above, but in Greenwich Mean
Time: Tuesday, 03-Jan-98 18:02:35 EST
- <!--#echo var="DOCUMENT_URI" -->
- The URI (the path form document root) of this
document is: /manual/man7.htm
- <!--#echo var="LAST_MODIFIED" -->
- This document was last modified: Friday, 01-Nov-96
15:22:57 EST
- <!--#echo var="HTTP_REFERER" -->
- The user came by way of a link from:
http://www.youthofamerica.net/lw/index.html
- <!--#echo var="HTTP_USER_AGENT"
-->
- The browser used to access this document was:
Mozilla/4.0b3 [en] (WinNT; I)
Echo
Command Values
SERVER_SOFTWARE server application
SERVER_NAME hostname of the server
SERVER_PROTOCOL server protocol
SERVER_PORT listening TCP port
REQUEST_METHOD HTTP method used by the client
REMOTE_HOST domain name of the client, note DNS option must
be set
REMOTE_ADDR IP address of the client
AUTH_TYPE method that the client used for authorization
REMOTE_USER username entered by the remote client
CONTENT_TYPE MIME type of the content posted by the client
CONTENT_LENGTH size of the data posted by the client
DOCUMENT_NAME name of the document requested
DOCUMENT_URI URL of the document requested
DATE_LOCAL current date, format specified by the config
command
DATE_GMT The current GMT, format specified by the config
command
LAST_MODIFIED document modified date, format specified by the
config command
PAGE_COUNT number of hits on the current document
since server came on-line
TOTAL_HITS number of documents server has served since
coming on-line
REFERRER The URL of the document the viewer came from
The EXEC Command
The exec command executes a Unix command or CGI
script. It always takes the argument "cmd".
- <!--#exec cmd="/usr/bin/date" -->
This executes the Unix date command.
- <!--#exec cgi="./hello.cgi" -->
This executes the CGI script, hello.cgi.
If you look carefully you will notice the second line uses
the statement exec cgi opposed to the previous line which used exec cmd. The
second line is calling a CGI script that was written, the first a UNIX command. Here is
the perl code contained in hello.cgi:
#!/bin/perl
print "Hello";
exit;
All the environment variables passed to the CGI
script are the same as those for the shtml file itself.
So, you cannot pass a query string using a question
mark (?), as in:
<!--#exec
cmd="hello.cgi?query" -->
The query string passed to the CGI script will be
the same as the query string passed to the shtml file itself. If this file were referenced
as "ssi.shtml?snort", than the word "snort" would also be passed to
the "hello.cgi" script above.
The FSIZE Command
The fsize command returns the size of the specified
file in bytes. It uses the argument "virtual," which is the path to the file is
given relative to the document root (usually your www directory.)
To find the size of picture.gif, you would use:
<!--#fsize
virtual="graphics/picture.gif" -->
This would return then return the file size.
Your probably now asking, what can I use this
for? Example: You offer some files available for download on your site and would like to
give people an idea of how big the files are.
The FLASTMOD Command
The flastmod command returns the date the specified
file was last modified.
The flastmod command uses the argument
"virtual," which is the path to the file is given relative to the document root
(usually your www directory.)
To find the last modified date of a file, you would
use:
<!--#flastmod
virtual="filename.txt" -->
This would return: Friday, 06-Sep-96 03:36:06 EDT
The CONFIG Command
The config command is used to control how the
results of other SSI are displayed. There are three possible arguments: timefmt, sizefmt
and errmesg.
To set the format for the date to dd/mm/yy, you
will use:
<!--#config
timefmt="%d/%m/%y" -->
The date will now be displayed as: 03/06/97
The field descriptors used by this SSI tag are the
same as those used by the Unix date command.
Notice the dates displayed above this config
command use the normal date format, the one below it uses the new format.
To set the format for how file sizes are displayed,
you use:
<!--#config sizefmt="abbrev"
-->
or:
<!--#config sizefmt="bytes"
-->
Depending on whether you want the size given in
total bytes or abbreviated as "1k".
To set error message returned when an SSI tag
fails, use:
<!--#config errmsg="Error"
-->
A failed SSI tag will now return: Error
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