SSI Tutorial

SSI Tutorial

SSI (server-side includes) is a very useful tool in designing a web page for yourself, or for others. SSI is very easy to use, if you can use SSI at all. To find out if you can use SSI, first you have to know if your server allows SSI use. We'll be doing that first. This is a basic tutorial, simply to get you introduced to SSI and how to use it. Please note that SSI can create a major security hole in your site so be careful using it and never let your visitors have access to posting ssi tags of their own.

First off, let's check to see if your site is SSI compatible. To save you time, there are a few commonly known free web site providers that do not support SSI. A few of the most widely known are: GeoCities, Tripod, and FreeWeb. Xoom. If your site is at any of those places, then you need to change hosts if you want to use ssi. However, Hypermart for instance does allow ssi. If your site is not at one of those places, there are several ways to find out if you can use SSI.

The first way is to visit the home page of your web site provider and read the information found there. The information there will most likely mention whether or not SSI is supported. The second way is just to email your host and ask

The third way is to simply rename a file with an .shtml extension, insert some code from below, and see if it works.

Most, but not all, servers are configured so that only files with an .shtml extension will be parsed for SSI commands. This means that putting a SSI tag in a file with the extention .html will not work (hypermart allows SSI in .html files). But once again, contact your host.

Now that you know if your site supports the power of SSI, we will start with the syntax for a command. Every SSI command follows this basic sytax.

Notice here that there is no space between the . If the spacing is wrong, you will get an error and it will not work properly.

Now we can delve into the 5 basic SSI commands:

• #include
• #echo
• #exec
• #fsize
• #flastmod

The first command is #include. It allows you to include, or embed, another file into the .shtml file. However, #include will not include CGI script output. For that you must use #exec, as described below. There are two types of arguments for the #include command. They are virtual and file.

Both those commands take file.html and place all of its contents within your .shtml file. You can have plan text or HTML tags within the file since your browser will view both.

The second command I will introduce is #echo. Like a true echo, the #echo command echoes the environment variables. Some examples are using Echo Var:

AUTH_TYPE	client authorization method if any
CONTENT_LENGTH	size of input posted from client
CONTENT_TYPE	MIME type of content
DATE_GMT	The current GMT can be formatted using #config
DATE_LOCAL	current time/date, can be formatted using #config
DOCUMENT_NAME	document name that was requested
DOCUMENT_URI	URL of the document
LAST_MODIFIED	document modified date, can be formatted using #config
PAGE_COUNT	number of accesses to current document since server was brought on line
HTTP_REFERER	URL of the document the client came from
REMOTE_ADDR	Numeric IP address of the client
REMOTE_HOST	domain name of the client
REMOTE_USER	ID of user
REQUEST_METHOD	HTTP method: GET OR POST
SERVER_NAME	server hostname
SERVER_PORT	the port used by httpd
SERVER_PROTOCOL	Which version of Httpd compliance
SERVER_SOFTWARE	The name of the server software,
TOTAL_HITS	total pages served by server since brought on line

There are many other types of variables for #echo. Once you know how to use SSI more fluently, you can learn how to use them from the advanced tutorial!

The next SSI command to learn is #exec. #exec will execute a CGI script or a Unix (or Linux) command. Some examples of executing a CGI script using #exec are:

Now make named "myscript.cgi", or use one that you already have to test this out..

This would run the unix command located at /usr/bin/date.
This is only an example of what can be run by #exec.

In all likelihood you have at least one file on your page for download. And the people visiting your site probably want to know exactly how big the file is. Use this to solve that little problem: . Easy. The next SSI command is #flastmod. Below is an example that tells you when the file was last modified.