芳草苑

httpd.conf and php.ini, which has priority? I have done some experiments, and the conclusions are -

• php settings in php.ini can be overrided by httpd.conf (or some other Apache configuration files) with php_admin_value, php_admin_flag, php_value, and php_flag.
• However, I find on Linux, if php_admin_value, php_admin_flag, php_value, or php_flag can not be put inside of VirtualHost block. They can be put inside of Directory block, but if Directory is inside of VirtualHost, they won’t work. I assume it is a php bug because on Windows php_admin_value, php_admin_flag, php_value, or php_flag can be inside of VirtualHost or Directory blocks.
• Some of php directives can only be set by php_admin_value or php_admin_flag, for example, safe_mode. Others can be set by php_admin or php_(non_admin), for example, display_errors. But if display_errors is set by php_admin, it is not overridable by .htaccess; if display_errors is set by php_(non_admin), .htaccess can override it.

今天在apache上搞基础建设，为一个小小的问题排错排了很长时间，事后想想，不就是一个简单的VirtualHost默认值的问题嘛！排完以后我才想来，其实以前已经碰到过这个问题，在一个问题绊住两次脚，浪费了一天，真是不应该！

每个VirtualHost里有一个ServerName，还可以有零个及以上ServerAlias。假设一个 domain name example.com 的 ip address 是 201.202.203.204,  如果 example.com 在 .conf 文件里找不到同时匹配的 VirtualHost 和 ServerName (或ServerAlias)，那么 example.com 将使用首个匹配的 VirtualHost （通常是 *：80 或 201.202.203.204：80）的设置。

我把apache VirtualHost的心得写下来，免得以后再绊脚。

这个问题不大。如果是我自己手写Apache conf文件，我一般不会用到NameVirtualHost。

我发现这个问题出现在Godaddy Server上，预装的是Godaddy自带的Simple Control Panel。Simple Control Panel会把Virtual Host信息保存在simplepanel.conf。如果通过Simple Control Panel重启Apache，不会看到任何症状；但如果在ssh下运行/etc/init.d/httpd restart，就会有若干个Warning “NameVirtualHost xxx.xxx.xxx.xxx:80 has no VirtualHosts”。

Simple Control Panel为每个配置的域名都添加一个ip-based NameVirtualHost directive，其实是不必要的，过多相同的NameVirtualHost就导致了Warning，删掉就可以了。