php从数据库里读出代码然后执行怎么实现？

CBD5C0CFCAA6

很久以前看见过，一时找不到了
网页比较慢，想到的办法之一是把include文件放到heap表里面

backwang

能说明确一点吗

CBD5C0CFCAA6

就是预先把代码存到数据库里面,需要运行它的时候再读出来
别的好说, 问题是读出来怎么插到脚本里面

xabbca

不知道你想干什么

lnux

原帖由 "CBD5C0CFCAA6" 发表：
就是预先把代码存到数据库里面,需要运行它的时候再读出来
别的好说, 问题是读出来怎么插到脚本里面

估计你的意思是这样：
echo "从数据库读出的代码";

CBD5C0CFCAA6

如果怎么也不明白也罢了
在这种专业论坛里面, 调侃很酷吗?

imbiss

按照我的理解。楼主的意思是
比如我在数据库里保存 <?php print "Hallo"; ?>;
我们可以通过访问数据库，把它显示出从来，但是不能执行。

我所能想到的办法
如果有写权限，可以把它写入一个文件里，然后再include进来

sleep_meng

Folow is my test. You can try it for yourself.

1. 
   
2. <?php
   
3. $str = "<?php ";
   
4. $str .= "echo \"hello 0<br/>;\";";
   
5. $str .= "echo \"hello 1<br>;\";";
   
6. $str .= "echo \"hello 2<br>;\";";
   
7. $str .= "echo \"hello 3<br>;\";";
   
8. $str .= "echo \"hello 4<br>;\";";
   
9. $str .= "echo \"hello 5<br>;\";";
   
10. $str .= " ?>;";
    
11. $std = shell_exec("echo '$str' | php");
    
12. echo substr($std,49);
    
13. ?>;
    
14. 
    
15. Outpu:
    
16. 
    
17. hello 0
    
18. hello 1
    
19. hello 2
    
20. hello 3
    
21. hello 4
    
22. hello 5
    

复制代码

lnux

原帖由 "CBD5C0CFCAA6" 发表：
如果怎么也不明白也罢了
在这种专业论坛里面, 调侃很酷吗?

其实你写的东西就是很难让人明白，根本就不知道你要干什么，回答你的问题的人也是猜测你的意思去回答，可能答非所问。

lares

eval
(PHP 3, PHP 4 )

eval -- Evaluate a string as PHP code
Description
mixed eval ( string code_str)


eval() evaluates the string given in code_str as PHP code. Among other things, this can be useful for storing code in a database text field for later execution.

There are some factors to keep in mind when using eval(). Remember that the string passed must be valid PHP code, including things like terminating statements with a semicolon so the parser doesn't die on the line after the eval(), and properly escaping things in code_str.

Also remember that variables given values under eval() will retain these values in the main script afterwards.

A return statement will terminate the evaluation of the string immediately. In PHP 4, eval() returns NULL unless return is called in the evaluated code, in which case the value passed to return is returned. In PHP 3, eval() does not return a value.

例子 1. eval() example - simple text merge

<?php
$string = 'cup';
$name = 'coffee';
$str = 'This is a $string with my $name in it.';
echo $str. "\n";
eval("\$str = \"$str\";";
echo $str. "\n";
?>;  

The above example will show:

This is a $string with my $name in it.
This is a cup with my coffee in it.