Writers

一个Writer是继承自Zend_Log_Writer_Abstract类的一个对象.Writer的职责是向存储后端纪录日志数据.

写入到流(Streams)

Zend_Log_Writer_Stream 写入日志数据到 » PHP 流中.

要把日志写入到输出缓冲区,使用URLphp:://output. 或则你可以直接发送日志数据到像STDERR 这样的流中(php://stderr).

$writer = new Zend_Log_Writer_Stream('php://output');
$logger = new Zend_Log($writer);

$logger->info('Informational message');

写入日志数据到一个文件,使用» Filesystem URLs之一:

$writer = new Zend_Log_Writer_Stream('/path/to/logfile');
$logger = new Zend_Log($writer);

$logger->info('Informational message');

默认情况流一个追加("a")的方式打开.要以不同的模式打开,Zend_Log_Writer_Stream 构造函数接受第二个参数作为可选的模式参数.

Zend_Log_Writer_Stream还接受一个现有的流资源:

$stream = @fopen('/path/to/logfile', 'a', false);
if (! $stream) {
    throw new Exception('Failed to open stream');
}

$writer = new Zend_Log_Writer_Stream($stream);
$logger = new Zend_Log($writer);

$logger->info('Informational message');

你不能给现有的流资源指定模式.这样作将导致抛出一个Zend_Log_Exception异常.

写入到数据库

Zend_Log_Writer_Db使用Zend_Db写入日志信息到数据库表中. Zend_Log_Writer_Db的构造函数接受一个Zend_Db_Adapter 实例,一个表名,和一个数据库字段到事件数据项的映射:

$params = array ('host'     => '127.0.0.1',
                 'username' => 'malory',
                 'password' => '******',
                 'dbname'   => 'camelot');
$db = Zend_Db::factory('PDO_MYSQL', $params);

$columnMapping = array('lvl' => 'priority', 'msg' => 'message');
$writer = new Zend_Log_Writer_Db($db, 'log_table_name', $columnMapping);

$logger = new Zend_Log($writer);

$logger->info('Informational message');

上面的例子写入单个行到名称为log_table_name的数据库表中.数据库字段lvs 接收优先级号,名为msg的字段接收日志消息.

踩熄Writer

Zend_Log_Writer_Null是一个不向任何地方写入任何数据的存根. 用于在测试期间关闭或踩熄日志.

$writer = new Zend_Log_Writer_Null;
$logger = new Zend_Log($writer);

// goes nowhere
$logger->info('Informational message');

测试 Mock

Zend_Log_Writer_Mock是一个非常简单的Writer,它纪录所接收到的原始的数据到到作为public属性的数组中.

$mock = new Zend_Log_Writer_Mock;
$logger = new Zend_Log($mock);

$logger->info('Informational message');

var_dump($mock->events[0]);

// Array
// (
//    [timestamp] => 2007-04-06T07:16:37-07:00
//    [message] => Informational message
//    [priority] => 6
//    [priorityName] => INFO
// )

清空有mock记录的日志,设置$mock->events = array()即可.

组合Writers

没有复合Writer对象,但是一个Log实例可以有任意个Writer.使用addWriter方法添加Writer:

$writer1 = new Zend_Log_Writer_Stream('/path/to/first/logfile');
$writer2 = new Zend_Log_Writer_Stream('/path/to/second/logfile');

$logger = new Zend_Log();
$logger->addWriter($writer1);
$logger->addWriter($writer2);

// goes to both writers
$logger->info('Informational message');