Programming PHP

}
ob_start('rewrite');
?>
Visit our site now!
Visit our site now!
Compressing Output
Recent browsers support compressing the text of web pages; the server sends compressed
text and the browser decompresses it. To automatically compress your web
page, wrap it like this:
The built-in ob_gzhandler( ) function is designed to be used as a callback with ob_
start( ). It compresses the buffered page according to the Accept-Encoding header
sent by the browser. Possible compression techniques are gzip, deflate, or none.
It rarely makes sense to compress short pages, as the time for compression and
decompression exceeds the time it would take to simply send the uncompressed text.
It does make sense to compress large (greater than 5 KB) web pages, though.
Instead of adding the ob_start( ) call to the top of every page, you can set the
output_handler option in your php.ini file to a callback to be made on every page. For
compression, this is ob_gzhandler.
Error Handling
Error handling is an important part of any real-world application. PHP provides a
number of mechanisms that you can use to handle errors, both during the development
process and once your application is in a production environment.
Error Reporting
Normally, when an error occurs in a PHP script, the error message is inserted into
the script’s output. If the error is fatal, the script execution stops.
There are three levels of conditions: notices, warnings, and errors. A notice is a condition
encountered while executing a script that could be an error but could also be
encountered during normal execution (e.g., trying to access a variable that has not
been set). A warning indicates a nonfatal error condition; typically, warnings are displayed
when calling a function with invalid arguments. Scripts will continue executing
after issuing a warning. An error indicates a fatal condition from which the script
cannot recover. A parse error is a specific kind of error that occurs when a script is
syntactically incorrect. All errors except parse errors are runtime errors.
This is the Title of the Book, eMatter Edition
Copyright © 2002 O’Reilly & Associates, Inc. All rights reserved.
Error Handling | 303