数据过滤、格式化用户输入 php笔记
1.过滤
abstract class Filter{
protected $blackstr = array();
protected $whitestr = array();
abstract function filtit($str);
}
//过滤用户名的特殊符号
class LoginFilter extends Filter {
function filtit($str){
$this->blackstr = array("/[\x7f-\xff]/","/\W/");
return preg_replace($this->blackstr,"",$str);
}
}
//对输入的文本框内容过滤
class EditFilter extends Filter {
function filtit($str){
$this->blackstr = array("/\&/", "/\"/", "/\"/", "/\", "/\>/",
"/\\\\/", "/\//", "/-/", "/\*/", "/ /" );
$this->whitestr = array("&","'","","\'","/","-","*"," ");
return preg_replace($this->blackstr,$this->whitestr,$str);
}
}
2.//用户的留言是一段代码:比如是js脚本;那么怎样及时避免数据的危害,取出数据时又正确显示
$js = "<script>alert('look me');</script>";//假设用户输入的是脚本
//$str1 = base64_encode($js);//使用 MIME base64 对数据进行编码
//echo $str1."
";
//$str2 = base64_decode($str1);//
echo htmlspecialchars($js);//转换特殊字符为HTML字符编码

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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