Programmer's Reference Guide
| Writers |
Formatters
A Formatter is an object that is responsible for taking an event array
describing a log event and outputting a string with a formatted log line.
Some Writers are not line-oriented and cannot use a Formatter. An example is the Database Writer, which inserts the event items directly into database columns. For Writers that cannot support a Formatter, an exception is thrown if you attempt to set a Formatter.
Simple Formatting
Zend_Log_Formatter_Simple is the default formatter. It is configured
automatically when you specify no formatter. The default configuration is equivalent
to the following:
<?php
$format = '%timestamp% %priorityName% (%priority%): %message%' . PHP_EOL;
$formatter = new Zend_Log_Formatter_Simple($format);
A formatter is set on an individual Writer object using the Writer's
setFormatter() method:
<?php
$writer = new Zend_Log_Writer_Stream('php://output');
$formatter = new Zend_Log_Formatter_Simple('hello %message%' . PHP_EOL);
$writer->setFormatter($formatter);
$logger = new Zend_Log();
$logger->addWriter($writer);
$logger->info('there');
// outputs "hello there"
The constructor of Zend_Log_Formatter_Simple accepts a single
parameter: the format string. This string contains keys surrounded by
percent signs (e.g. %message%). The format string may
contain any key from the event data array.
Formatting to XML
Zend_Log_Formatter_Xml formats log data into XML strings.
By default, it automatically logs all items in the event data array:
<?php
$writer = new Zend_Log_Writer_Stream('php://output');
$formatter = new Zend_Log_Formatter_Xml();
$writer->setFormatter($formatter);
$logger = new Zend_Log();
$logger->addWriter($writer);
$logger->info('informational message');
The code above outputs the following XML (space added for clarity):
<logEntry>
<timestamp>2007-04-06T07:24:37-07:00</timestamp>
<message>informational message</message>
<priority>6</priority>
<priorityName>INFO</priorityName>
</logEntry>
It's possible to customize the root element as well as specify a mapping
of XML elements to the items in the event data array. The constructor
of Zend_Log_Formatter_Xml accepts a string with the name of
the root element as the first parameter and an associative array with
the element mapping as the second parameter:
<?php
$writer = new Zend_Log_Writer_Stream('php://output');
$formatter = new Zend_Log_Formatter_Xml('log', array('msg' => 'message', 'level' => 'priorityName'));
$writer->setFormatter($formatter);
$logger = new Zend_Log();
$logger->addWriter($writer);
$logger->info('informational message');
logEntry to log. It also maps the element
msg to the event data item message. This
results in the following output:
<log>
<msg>informational message</msg>
<level>INFO</level>
</log>
| Writers |