PHP-在复杂的应用程序中打印回溯
PHPdebug_backtrace[man]函数对于了解在何处调用函数/方法非常有用。
它打印代码的后跟踪。
示例：在当前使用的框架中，有ORM类来访问DB。因此，需要很长时间才能了解在需要时在哪里启动查询。解决方案：在全局变量（或类的字段）中保存已启动查询的列表以及已启动每个查询的代码。
代码：
class DB {
# …
public function query($query) {
if (DEBUG_MODE) { ##
$_dbt = debug_backtrace();
$_fromFile = isset( $_dbt[0]['file']) ? str_replace(_ROOT, “”,$_dbt[0]['file']) : “”;
$_fromLine = isset( $_dbt[0]['line']) ? $_dbt[0]['line'] : “”;
$_launchedFrom = “launched from $_fromFile:$_fromLine“;
$this->logQueries[] = “[$query][$_launchedFrom]“;
# ..query.
}
}
# …
}结果示例：
Array ( [0] => [set names utf8][launched from C:\wamp\www\dev\index.php:68] [1] => [SELECT * FROM `Setting` WHERE `id` = 1][launched from \class\Setting.class.php:20] [2] => [SELECT id FROM `User`WHERE id = 293968 LIMIT 1][launched from \class\User.class.php:598] [3] => [SELECT * FROM `User` WHERE `id` = 293968][launched from \class\User.class.php:45] [4] => [SELECTf.store_idFROM `Store_Monthly_Featured` f ORDER BYf.orderASC][launched from \class\Store_Monthly_Featured.class.php:16] )
仅打印行和数字的有用功能
function debug_backtrace_filelines() {
$ret = array();
$b = debug_backtrace();
foreach ($b as $elements) {
$ret[] = $elements['file'].‘:’.$elements['line'];
}
}