


In-depth understanding of PHP Error and Logging functions_PHP Tutorial
PHP Error and Logging Introduction
error and logging functions allow you to process and log errors. The
error function allows users to define error handling rules and modify the way errors are logged. The
logging function allows users to log applications and send log messages to email, system logs, or other machines.
Installation
The error and logging functions are part of the core of PHP. No installation is required to use these functions.
PHP Error and Logging functions
PHP: Indicates the earliest PHP version that supports this function.
Function Description PHP
debug_backtrace() generates backtrace. 4
debug_print_backtrace() output backtrace. 5
error_get_last() Get the last error that occurred. 5
error_log() Send an error to the server error log, file or remote target. 4
error_reporting() specifies which error to report. 4
restore_error_handler() Restores the previous error handler. 4
restore_exception_handler() Restores the previous exception handler. 5
set_error_handler() Set user-defined error handling function. 4
set_exception_handler() Sets a user-defined exception handling function. 5
trigger_error() Create user-defined error message. 4
user_error() Alias of trigger_error(). 4
PHP Error and Logging constants
PHP: Indicates the earliest PHP version that supports this constant.
Value Constant Description PHP
1 E_ERROR Fatal runtime error. The error cannot be recovered. Execution of the script was interrupted.
2 E_WARNING Non-fatal runtime error. The execution of the script is not interrupted.
4 E_PARSE Compile-time syntax parsing error. Parsing errors should only be generated by the parser.
8 E_NOTICE Runtime prompt. It could be a bug or it could happen while running the script normally.
16 E_CORE_ERROR Error generated internally by PHP. 4
32 E_CORE_WARNING Warning generated internally by PHP. 4
64 E_COMPILE_ERROR An error generated internally by the Zend script engine. 4
128 E_COMPILE_WARNING A warning generated internally by the Zend script engine. 4
256 E_USER_ERROR A runtime error generated by calling the trigger_error() function. 4
512 E_USER_WARNING A runtime warning generated by calling the trigger_error() function. 4
1024 E_USER_NOTICE A runtime prompt generated by calling the trigger_error() function. 4
2048 E_STRICT runtime prompt. It is beneficial to enhance code interoperability and compatibility. 5
4096 E_RECOVERABLE_ERROR Trapable fatal error. (See set_error_handler()) 5
8191 E_ALL All errors and warnings except E_STRICT. 5

TomakePHPapplicationsfaster,followthesesteps:1)UseOpcodeCachinglikeOPcachetostoreprecompiledscriptbytecode.2)MinimizeDatabaseQueriesbyusingquerycachingandefficientindexing.3)LeveragePHP7 Featuresforbettercodeefficiency.4)ImplementCachingStrategiessuc

ToimprovePHPapplicationspeed,followthesesteps:1)EnableopcodecachingwithAPCutoreducescriptexecutiontime.2)ImplementdatabasequerycachingusingPDOtominimizedatabasehits.3)UseHTTP/2tomultiplexrequestsandreduceconnectionoverhead.4)Limitsessionusagebyclosin

Dependency injection (DI) significantly improves the testability of PHP code by explicitly transitive dependencies. 1) DI decoupling classes and specific implementations make testing and maintenance more flexible. 2) Among the three types, the constructor injects explicit expression dependencies to keep the state consistent. 3) Use DI containers to manage complex dependencies to improve code quality and development efficiency.

DatabasequeryoptimizationinPHPinvolvesseveralstrategiestoenhanceperformance.1)Selectonlynecessarycolumnstoreducedatatransfer.2)Useindexingtospeedupdataretrieval.3)Implementquerycachingtostoreresultsoffrequentqueries.4)Utilizepreparedstatementsforeffi

PHPisusedforsendingemailsduetoitsbuilt-inmail()functionandsupportivelibrarieslikePHPMailerandSwiftMailer.1)Usethemail()functionforbasicemails,butithaslimitations.2)EmployPHPMailerforadvancedfeatureslikeHTMLemailsandattachments.3)Improvedeliverability

PHP performance bottlenecks can be solved through the following steps: 1) Use Xdebug or Blackfire for performance analysis to find out the problem; 2) Optimize database queries and use caches, such as APCu; 3) Use efficient functions such as array_filter to optimize array operations; 4) Configure OPcache for bytecode cache; 5) Optimize the front-end, such as reducing HTTP requests and optimizing pictures; 6) Continuously monitor and optimize performance. Through these methods, the performance of PHP applications can be significantly improved.

DependencyInjection(DI)inPHPisadesignpatternthatmanagesandreducesclassdependencies,enhancingcodemodularity,testability,andmaintainability.Itallowspassingdependencieslikedatabaseconnectionstoclassesasparameters,facilitatingeasiertestingandscalability.

CachingimprovesPHPperformancebystoringresultsofcomputationsorqueriesforquickretrieval,reducingserverloadandenhancingresponsetimes.Effectivestrategiesinclude:1)Opcodecaching,whichstorescompiledPHPscriptsinmemorytoskipcompilation;2)DatacachingusingMemc


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