捕获php中的错误与异常

关于配置

1、display_errors

; This directive controls whether or not and where PHP will output errors,
; notices and warnings too. Error output is very useful during development, but
; it could be very dangerous in production environments. Depending on the code
; which is triggering the error, sensitive information could potentially leak
; out of your application such as database usernames and passwords or worse.
; For production environments, we recommend logging errors rather than
; sending them to STDOUT.
; Possible Values:
;   Off = Do not display any errors
;   stderr = Display errors to STDERR (affects only CGI/CLI binaries!)
;   On or stdout = Display errors to STDOUT
; Default Value: On
; Development Value: On
; Production Value: Off
; http://php.net/display-errors
display_errors = Off
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此配置会将errors,notices,warnings类型的信息发送给标准输出STDOUT，也就是会打印出错误信息，建议开发环境设置为On，正式环境设置为Off。

运行时设置ini_set('display_errors', TRUE);

2、error_reporting

; This directive informs PHP of which errors, warnings and notices you would like
; it to take action for. The recommended way of setting values for this
; directive is through the use of the error level constants and bitwise
; operators. The error level constants are below here for convenience as well as
; some common settings and their meanings.
; By default, PHP is set to take action on all errors, notices and warnings EXCEPT
; those related to E_NOTICE and E_STRICT, which together cover best practices and
; recommended coding standards in PHP. For performance reasons, this is the
; recommend error reporting setting. Your production server shouldn't be wasting
; resources complaining about best practices and coding standards. That's what
; development servers and development settings are for.
; Note: The php.ini-development file has this setting as E_ALL. This
; means it pretty much reports everything which is exactly what you want during
; development and early testing.
;
; Error Level Constants:
; E_ALL             - All errors and warnings (includes E_STRICT as of PHP 5.4.0)
; E_ERROR           - fatal run-time errors
; E_RECOVERABLE_ERROR  - almost fatal run-time errors
; E_WARNING         - run-time warnings (non-fatal errors)
; E_PARSE           - compile-time parse errors
; E_NOTICE          - run-time notices (these are warnings which often result
;                     from a bug in your code, but it's possible that it was
;                     intentional (e.g., using an uninitialized variable and
;                     relying on the fact it is automatically initialized to an
;                     empty string)
; E_STRICT          - run-time notices, enable to have PHP suggest changes
;                     to your code which will ensure the best interoperability
;                     and forward compatibility of your code
; E_CORE_ERROR      - fatal errors that occur during PHP's initial startup
; E_CORE_WARNING    - warnings (non-fatal errors) that occur during PHP's
;                     initial startup
; E_COMPILE_ERROR   - fatal compile-time errors
; E_COMPILE_WARNING - compile-time warnings (non-fatal errors)
; E_USER_ERROR      - user-generated error message
; E_USER_WARNING    - user-generated warning message
; E_USER_NOTICE     - user-generated notice message
; E_DEPRECATED      - warn about code that will not work in future versions
;                     of PHP
; E_USER_DEPRECATED - user-generated deprecation warnings
;
; Common Values:
;   E_ALL (Show all errors, warnings and notices including coding standards.)
;   E_ALL & ~E_NOTICE  (Show all errors, except for notices)
;   E_ALL & ~E_NOTICE & ~E_STRICT  (Show all errors, except for notices and coding standards warnings.)
;   E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR  (Show only errors)
; Default Value: E_ALL & ~E_NOTICE & ~E_STRICT & ~E_DEPRECATED
; Development Value: E_ALL
; Production Value: E_ALL & ~E_DEPRECATED & ~E_STRICT
; http://php.net/error-reporting

error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT
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此配置是报告哪些错误类型。默认值为E_ALL & ~E_DEPRECATED & ~E_STRICT。

其中E_ALL & ~E_NOTICE 等价于 E_ALL ^E_NOTICE，意为报告所有信息，除了E_NOTICE类型。

运行时设置error_reporting(E_ALL ^E_NOTICE);

返回当前的报告级别 error_reporting();

错误码类型：

try…catch 能做什么

可以捕获异常和错误，在php中有预定义的异常和错误，系统会自动抛出，这些是可以通过try...catch来捕获的。

https://www.php.net/manual/en/reserved.exceptions.php

Exception
ErrorException
Error
ArgumentCountError
ArithmeticError
AssertionError
DivisionByZeroError
CompileError
ParseError
TypeError
ValueError
UnhandledMatchError
FiberError
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我们最常用的捕获自定义的异常

try {
    throw new MyException('xxx');
} catch (MyException $e){
    
}
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假如我们调用了一个未定义的方法，那么内核会抛出一个预定义的Error，比如Uncaught Error: Call to undefined function checkOrderFormats() in /www/chpay/api/order_status.php:29这是一个E_ERROR类型，会导致程序中止。

此时我们可以这样写

try {
    checkOrderFormats();
    throw new MyException('xxx');
} catch (MyException $e){
    
} catch (Error $e){
    
}
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于是我们会发现，php内置的预定义Exception和Error挺多的，再加上我们自定义的Exception，要想通过try...catch来全部捕获他们实在不现实，也不友好。

register_shutdown_function

此函数在php中止时被执行。在这个函数里我们可以获取到没有被try…catch捕获或其他程序处理的错误，并记录到日志文件中。

register_shutdown_function("shutdownLog");

function shutdownLog()
{
	if (!is_null($e = error_get_last())) {
		addLog($e['message'], "ERROR");
	}
}
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上面提到的调用了一个未定义的方法会导致程序中止，在此处就可以被捕获到，当然，如果你使用了try...catch捕获了预定义的Error，那么此处就没有了。

set_error_handler

设置用户自定义的错误处理函数，自定义的错误类型指的是E_USER_ERROR，E_USER_WARNING，E_USER_NOTICE。

set_error_handler("myErrorHandlerLog", E_ALL ^ E_NOTICE);

function myErrorHandlerLog($errno, $errstr, $errfile, $errline)
{
	addLog(sprintf("[%d] %s in %s:%d", $errno, $errstr, $errfile, $errline), "ERROR");
	return true;
}
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此处如果返回false，那么错误信息将会继续向下传导，因此返回true即可。

上面提到的调用了一个未定义的方法（E_ERROR），在此处没有捕获到，另外它还不能捕获E_ERROR、 E_PARSE、 E_CORE_ERROR、 E_CORE_WARNING、 E_COMPILE_ERROR、E_COMPILE_WARNING，以及在调用 set_error_handler() 函数所在文件中产生的大多数 E_STRICT。

重要的是要记住 error_types 里指定的错误类型都会绕过 PHP 标准错误处理程序， 除非回调函数返回了 false。 error_reporting() 设置将不会起到作用而你的错误处理函数继续会被调用 —— 不过你仍然可以获取 error_reporting 的当前值，并做适当处理。 需要特别注意的是带 @ error-control operator 前缀的语句发生错误时，这个值会是 0。

但是我发现它能捕获E_WARNING的错误，比如$a = 10 / 0;

总结

最终的错误处理的方式

error_reporting(E_ALL);
ini_set('display_errors', FALSE);

// 位置尽量靠前
register_shutdown_function("shutdownLog");
set_error_handler("myErrorHandlerLog", E_ALL);

function shutdownLog()
{
	if (!is_null($e = error_get_last())) {
		addLog(sprintf("[%d] %s in %s:%d", $e['type'], $e['message'], $e['file'], $e['line']), "ERROR");
	}
}

function myErrorHandlerLog($errno, $errstr, $errfile, $errline)
{
	addLog(sprintf("[%d] %s in %s:%d", $errno, $errstr, $errfile, $errline), "ERROR");
	return true;
}
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基本上就能捕获所有的信息了。