Server-Side Processing

Server-side processing involves using the web server to interpret and process input on a web page.
The files to be processed can be stored on the server and inserted into the web page by the server when the user accesses the page.

Sorts of uses

• Form processing.
• Building and displaying pages created from a database
• Guestbooks
• BBS systems
• Chat systems
• Mailing lists
• Database manipulation
• Searches
• Form processing
• Shopping carts
• Surveys sed to run all sorts of applications that require dynamic processing

(1) CGI Script Processing

A lot of serverside processing is run by serverside scripts

Those written in Perl, Python, C, C++ are commonly called CGI scripts (Common Gateway Interface) and will be linked to HTML pages to process tasks.

The script is created to do a specific job and is stored in a specific folder/directory on the web server. (commonly called cgi bin) in your own web area or is held on the central web server.To process it a command is embedded into your page which is then acted upon by the server.

NB Your web account may not support CGI scripts - if it does you will have cgi-bin and can use serverside scripts.

(PHP scripts and ASP, JSP scripts will be saved as separate pages on the server and not in a cgi-bin).

(2) PHP, ASP, JSP, and CFML scripting technologies
These are termed 'server-side processing technologies' and are other ways of processing forms and creating dynamic web pages. The web server you are using must support scripts in these formats.
Pages made using these languages are uploaded as normal to the main directory of the site, not into the cgi-bin.

Windows based servers commonly support ASP scripting and Linux based servers PHP scripting.

(3) Server-side Includes
The files to be processed can be stored on the server and inserted into the web page by the server when the user accesses the page
This can be done by inserting a 'server-side include' into your page or by using serverside processsing technologies.

See Serverside Includes

There are different types of SSI each doing particular jobs

• include - allows a section of code to be inserted in a file

• echo - allows you to insert environment variables such as LAST_MODIFIED, DOCUMENT_NAME, DATE_LOCAL, SERVER_NAME
  Syntax is <!-- #echo var=" " -->

• fsize - inserts the file size of the file specified.
  Syntax is <!-- #fsize file=" " -->

• exec - parameter cgi will exec a file like a cgi script to allow it to work to carry out processing word on a page of HTML.
  Syntax is <!-- #exec cgi="/cgi-bin/script.pl " -->
• Parameter cmd will take any command that runs on a server.
  Typical syntax is <!-- #cmd ="/bin/ls -1 /home/www/public_html" --> This will return listing of the public_html folder on your server

• flastmod - returns the modification date of the file specified
  Syntax is <!-- #flast file=" " -->

• config allows you to tailor the output of other ssi on the page
  eg to configure DATE_LOCAL the command <!--#config timefmt="%H:%M:%S"--> might be given so that it only displays time.

The Time and Date and Modified commands are echo commands and are ssi includes on this page

This is your local Date: Saturday, 11-Oct-2008 20:26:24 GMT
Modification date of this page Tuesday, 29-Jan-2008 11:34:27 GMT