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Performance Issues
If you have already read the performance issues in the SSI section, you can skip
this section as the information is basically the same.
Before you decide to start using PHP you should be aware of the performance issues
involved. Basically, it slows down the loading of your documents.
On a standard server setup without PHP, when a document is requested it opens the file and sends
the contents back to the requesting browser. The server does not attach any meaning to the
contents, or even check that it is what you say it is.
For instance, if you accidentally placed a sound or image into a file called
mypage.html, the server would neither know or care. It just supplies the file to the
browser byte for byte.
With PHP installed and enabled, the server has to work a lot harder. It has to look at the
contents of files and try to process them. Although it doesn't have to act on the entire
contents, it does have to search for and act on any special PHP commands the document contains.
If the command is to include the content of another document, it has to open that document and
process it too. If the scripting language is used, it also has to use precious CPU time for
that.
All this searching and processing takes time - enough time to be noticeable to visitors.
You are going to have to decide whether the reduced development time is enough of a reason to slow
down the delivery of your pages.
Having said that, in many cases using PHP instead of a combination of SSI and CGI can actually
be quicker. It is still noticeably slower than static HTML though.
Restrictions
There are also several restrictions on using PHP at Spaceports:-
- Location
- Any documents containing PHP commands and related files to be included must be on the CGI-BIN
server. (See the CGI-BIN section for restrictions inherent
in using that server.)
File names- HTML documents containing PHP code must have an extension of .php for the commands
within them to be processed. Included files do not have this restriction, unless they too
contain PHP code.
Version- The version of PHP installed is currently PHP 4. Certain functions from previous versions
of PHP do not work as intended, or in some cases at all. Most freeware scripts you find
should by now have a PHP 4 compatible version available (PHP 4 files usually have a .php
extension instead of .php3)
Commands- The options available for sending server commands via PHP are restricted for security
reasons.
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