PHP当字符串是mysqli_real_escape_string的两倍时会发生什么 [英] PHP what happens when a string is double times mysqli_real_escape_string

问题描述

当回显 mysqli_real_escape_string（$ db，mysqli_real_escape_string（$ db，''））;

其中一个将是输出：
1. \
2. \\\
？

是否一个安全的方法来检查一个字符串是否已被转义？

不幸的是，目前我无法测试，因为我无法访问MySQL 24小时。

解决方案

输出是 \\\（你的第二个例子） p>

我不认为你可以确定一个字符串是否已经被转义，你应该按照你只能调用 mysqli_real_escape_string（）一次。

I'm using mysqli.

When I echo mysqli_real_escape_string($db,mysqli_real_escape_string($db,'"'));

which one of those will be the output: 1. \" 2. \\\" ?

Is there a safe way to check whether a string has been already escaped?

Unfortunately, I cannot test at present as I cannot access MySQL for 24 hours.

解决方案

The output is \\\" (your second example).

I don't think you can reliably say whether a string has already been escaped or not, you should organize your code in a way that you only can call mysqli_real_escape_string() once.

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