PHP eval() - 只有一个函数 [英] PHP eval() - just one function

问题描述

有一些 PHP 代码分配给一个变量 ($phpCode)，该变量可能包含一个名为 runjustthis() 的函数或/和任何其他 php 代码.

There's some PHP code assigned to one variable ($phpCode) that may contain a function called runjustthis() or/and any other php code.

我正在寻找使用 eval() 仅运行该函数 runjustthis() 的可能性.

I'm looking for a possibility to run just that function runjustthis() with eval().

换句话说，我如何从字符串 $phpCode 中提取(使用正则表达式?)函数 runjustthis()，然后在提取的字符串上调用 eval()?

In other words, how do I extract (with a regex?) the function runjustthis() from the string $phpCode and then call eval() on the extracted string?

伪代码:

$phpCode = "
 function runjustthis() {
   // some code here...
 }
 
 // maybe some more code here...
  // Don't execute that: 
  $something = '123'; 
  somethingElse();
";

$runjustthis = extractFunction("runjustthis", $phpCode); 
eval($runjustthis);

推荐答案

您不需要其他任何东西.正如 doc 所说:

You do not need anything else. as the doc says:

代码将在调用 eval() 的代码范围内执行.因此，在 eval() 调用中定义或更改的任何变量在它终止后都将保持可见.

The code will be executed in the scope of the code calling eval(). Thus any variables defined or changed in the eval() call will remain visible after it terminates.

所以你只需要:

<?php
$phpCode = "
 function runjustthis() {
    return 'Hi';
 }
 
 function runjustthis2(){
     return 'working?';
 }
";

eval($phpCode);
echo runjustthis(). PHP_EOL;
echo runjustthis2();

输出

Hi
working?

但是如果你坚持只获得你想要的功能($phpCode 的一部分)，那么你可以这样做:

But if you insists on getting only the function you want(part of $phpCode), so you can do this:

<?php
$phpCode = "
 function runjustthis() {
    return 'Hi';
 }
 
 function runjustthis2(){
     return 'working?';
 }
";
function extractFunction($functionName, $code){
    $pattern = "/function (?<functionName>$functionName+)\(\)(\s+)?\{[^\}]+\}/m";
    preg_match_all($pattern, $code, $matches);
    return($matches[0][0]);
}

$runjustthis = extractFunction("runjustthis", $phpCode); 
eval($runjustthis);
echo runjustthis();

这只会执行 runjustthis() 函数，而不是在 $phpCode 中编写的其他代码，所以如果我们尝试 runjustthis2() 它会得到这个错误:

This would only execute the runjustthis() function not other codes which wrote in $phpCode, so if we try runjustthis2() it will get this error:

PHP Fatal error:  Uncaught Error: Call to undefined function runjustthis2() in your/file/directory/file_name.php

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