Php if（$ var）曾经工作过 [英] Php if($var) used to work

问题描述

我有一个网站的som代码，以前用得很好。我想检查是否设置了变量或会话。我使用了以下代码：

I have som code for a website, that used to work fine with. I want to check if a variable or session is set. I used the following code:

if ($_GET['something']){ //Do something }

现在我尝试在本地服务器上安装它，我得到一个错误代码，说有一个未定义的索引。

Now i try to install it on a local server, at i get a error code, saying that there is an undefined index.

它要求我这样做：

if (isset($_GET['']) { //Do something }

我可以快速解决这个问题，因为我不想更改代码那么多地方？

Can i make a quick fix for this, as i don't want to change the code so many places?

推荐答案

之前没有收到错误，因为你的error_reporting和/或display_error设置设置得过于宽泛。你的第一个片段 试图访问可能不存在的数组中的值。如果不是PHP 总是 发出通知。

只有在发出通知后才可以放心（通过关闭 display_errors 或设置 error_reporting 不报告通知（ ~E_NOTICE ）。

You didn't get the error before, because your error_reporting and/or display_error settings were set too forgiving. Your first snippet is attempting to access a value in an array that might not exist. If it doesn't PHP always issues a notice.
It's only after the notice has been issued that it can be hushed up (by turning off display_errors or setting error_reporting to not report notices (~E_NOTICE).

您要求快速修复：

if (isset($_GET['something']))

只要求你添加 isset（）。这很快，它解决了这个问题。此外：使用 isset 是你应该做的事情。总是。

only requires you to add isset(). That's quick, and it fixes the issue. Besides: using isset is what you should do. Always.

偏离主题，但也许有用：

正如我在评论中所解释的那样：现在最好的解决方法是解决问题本身，而不是忽略通知。为此，一个简单的脚本扫描你的项目目录中的.php文件（使用 glob ），读取它们并查找模式可能有用：

Off-topic, but perhaps useful:
As I've explained in the comments: the best course of action for you now is to fix the issue itself, not ignoring the notices. To that end, a simple script that scans your projects directories for .php files (using glob), reads them in and looks for a pattern might prove useful:

foreach ($phpFiles as $file)
{
    $code = file_get_contents($file);//read the file
    if (preg_match_all('/if\s*\(\$[^[]+\[[^]]+\]\s*\)/',$code, $matches))
    {//find all usages of "if ($rawVar['offset'])" in code
        echo 'Expressions to check or fix in file: ', $file,':', PHP_EOL, '=>';
        echo implode(PHP_EOL.'=>', $matches[0]), PHP_EOL;
    }
}

运行脚本，或许将输出写入temp文件，并设置为工作。输出应如下所示：

run the script, perhaps write the output to a temp file, and set to work. The output should look something like:

Expressions to check or fix in file: scriptname.php:
=> if ($_GET['something'])
=> if ($var[123])

依此类推。这是一种可行的格式，并且给定时间，您也可以编写脚本来自动重构代码。

也许在这里使用更全面（如完整的）正则表达式喜欢：

And so on. It's a workable format, and given time, you might be able to write a script for you to automatically refactor the code, too.
Perhaps a more comprehensive (as in complete) regex to use here would be something like:

/if\s*\((\|\||&&|\()?\$[^[]+\[[^]]+\]\s*(\|\||&&|\))?/

但是，这也有一些警告，但这是一个开始。

But this, too, has some caveats still, but it's a start.

添加作业 - 我还会为你做一个好处：添加修复你在赋值表达式中遇到的问题的代码，比如 $ var = $ _GET ['something']; 。这可以自动完成，也非常容易：

Adding assignments - I'll do you one more favour: adding code that fixes the issues you get in assignment expressions like $var = $_GET['something'];. This can be done automatically, and quite easily, too:

foreach ($phpFiles as $file)
{
    $code = file_get_contents($file);//read the file
    $clean = preg_replace(
        '/(\$[^\s]+\s*={1}\s*)(\$[^[]+[^]]+\])\s*;/',
        '$1isset($2) ? $2 : null;',
        $code
    );
    file_put_contents($file, $clean);
}

我已经测试过这样的代码：

I've tested this code like so:

$code = '$foo = 123;
$foo = $_GET["bar"];';
$clean = preg_replace(
    '/(\$[^\s]+\s*={1}\s*)(\$[^[]+[^]]+\])\s*;/',
    '$1isset($2) ? $2 : null;',
    $code
);
echo $clean, PHP_EOL;

它产生了预期的产出：

$foo = 123;
$foo = isset($_GET["bar"]) ? $_GET["bar"] : null;

结合这两个正则表达式，你应该很好地重构你拥有的代码......

Combine these two regex's and you should be well on your way to refactoring the code you have...

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