.. _zend.log.formatters:
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.
.. _zend.log.formatters.simple:
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:
.. code-block:: php
:linenos:
$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:
.. code-block:: php
:linenos:
$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();
$logger->addWriter($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. You can retrieve the default keys by using the DEFAULT_FORMAT constant from
``Zend\Log\Formatter\Simple``.
.. _zend.log.formatters.xml:
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:
.. code-block:: php
:linenos:
$writer = new Zend\Log\Writer\Stream('php://output');
$formatter = new Zend\Log\Formatter\Xml();
$writer->setFormatter($formatter);
$logger = new Zend\Log\Logger();
$logger->addWriter($writer);
$logger->info('informational message');
The code above outputs the following *XML* (space added for clarity):
.. code-block:: xml
:linenos:
2007-04-06T07:24:37-07:00
informational message
6
INFO
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:
.. code-block:: php
:linenos:
$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();
$logger->addWriter($writer);
$logger->info('informational message');
The code above changes the root element from its default of ``logEntry`` to ``log``. It also maps the element
``msg`` to the event data item ``message``. This results in the following output:
.. code-block:: xml
:linenos:
informational message
INFO
.. _zend.log.formatters.firebug:
Formatting to FirePhp
---------------------
``Zend\Log\Formatter\FirePhp`` formats log data for the `Firebug`_ extension for Firefox.
.. _`Firebug`: http://getfirebug.com/