During the development process, for example, if you want to modify the code developed by others or debug the problematic code, you need to track the code process step by step, find the problematic areas, and make modifications. If there is a method that can get which method a certain piece of code is called, and can go back to the place where it was first called (including the file called, the number of lines, parameters, etc.), it will be easy to locate the problem. place.
php's debug_backtrace method can trace code calls to facilitate debugging the code.
debug_backtrace method description
Generate a backtrace (backtrace)
array debug_backtrace ([ int $options = DEBUG_BACKTRACE_PROVIDE_OBJECT [, int $limit = 0 ]] )
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Parameters
options
##DEBUG_BACKTRACE_PROVIDE_OBJECT
Whether to fill the index of "object".
DEBUG_BACKTRACE_IGNORE_ARGS
Whether to ignore the index of "args", including all function/method parameters, can save memory overhead.
limit This parameter can be used to limit the number of stack frames returned. The default is (limit=0), and all stack frames are returned.
Return value
Returns an array containing many associative arrays. Possible returned elements:
名字 类型 说明function string 当前的函数名，参见： __FUNCTION__。
line integer 当前的行号。参见： __LINE__。
file string 当前的文件名。参见： __FILE__。class string 当前 class 的名称。参见 __CLASS__object object 当前的 object。
type string 当前调用的类型。如果是一个方法，会返回 "->"。如果是一个静态方法，会返回 "::"。 如果是一个函数调用，则返回空。
args array 如果在一个函数里，这会列出函数的参数。 如果是在一个被包含的文件里，会列出包含的文件名。
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Instance
To obtain the user information and user information of the order, the calling process is index->order->user->message, and finally returns the sorted information.
Suppose we find that the data of the message is incorrect during debugging, we can use the debug_backtrace method on the message to view the calling process and the parameters of the call, and check which step has the problem.
Use
DEBUG_BACKTRACE_IGNORE_ARGS will ignore args (parameters of method call)
index.php
<?phprequire 'order.php';// 获取用户订单资料$order_id = 1000000;$oOrder = new Order;$order_info = $oOrder->get_order($order_id);?>
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order.php
<?phprequire 'user.php';// 订单资料class Order{
// 获取订单资料
function get_order($order_id){
$user_id = 1001; // 获取用户资料
$oUser = new User; $user_info = $oUser->get_user($user_id); // 订单资料
$order_info = array( 'order_id' => $order_id, 'order_name' => 'my order', 'user_info' => $user_info,
); return $order_info;
}
}?>Copy after login
user.php
<?phprequire 'message.php';// 用户资料class User{
// 获取用户资料
function get_user($user_id){
// 获取用户讯息
$oMessage = new Message; $user_message = $oMessage->get_message($user_id); $user_info = array( 'user_id' => $user_id, 'name' => 'fdipzone', 'message' => $user_message
); return $user_info;
}
}?>Copy after login
message.php
<?php// 用户讯息class Message{
// 获取用户讯息
function get_message($user_id){
$message = array( array('id'=>1, 'title'=>'message1'), array('id'=>2, 'title'=>'message2'),
); // 加入跟踪调试
$backtrace = debug_backtrace();
var_dump($backtrace); return $message;
}
}?>Copy after login
Run index.php, output
/message.php:15:array (size=3) 0 =>
array (size=7) 'file' => string '/user.php' (length=9) 'line' => int 12
'function' => string 'get_message' (length=11) 'class' => string 'Message' (length=7) 'object' =>
object(Message)[3] 'type' => string '->' (length=2) 'args' =>
array (size=1) 0 => int 1001
1 =>
array (size=7) 'file' => string '/order.php' (length=10) 'line' => int 14
'function' => string 'get_user' (length=8) 'class' => string 'User' (length=4) 'object' =>
object(User)[2] 'type' => string '->' (length=2) 'args' =>
array (size=1) 0 => int 1001
2 =>
array (size=7) 'file' => string '/index.php' (length=9) 'line' => int 8
'function' => string 'get_order' (length=9) 'class' => string 'Order' (length=5) 'object' =>
object(Order)[1] 'type' => string '->' (length=2) 'args' =>
array (size=1) 0 => int 1000000Copy after login
, you can see that the calling process is
1.index. php
line 8
class Order
function get_order
args int 1000000
2.order.php
line 14
class User
function get_user
args int 1001
3.user.php
line 12
class Message
function get_message
args int 1001
This article explains the implementation through php The debug_backtrace method tracks code calls. For more related content, please pay attention to the PHP Chinese website.
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