Nginx模块讲解_http_sub_module

1、http_sub_module详解

（1）http_sub_module作用

（2）举例

    location / {
        sub_filter '<a href="http://127.0.0.1:8080/'  '<a href="https://$host/';
        sub_filter '<img src="http://127.0.0.1:8080/' '<img src="https://$host/';
        sub_filter_once on;
    }

2、sub语法

（1）sub_filter语法

Syntax:	sub_filter string replacement;
Default:	—
Context:	http,server,location

语法解释：

sub_filter string replacement；

string 表示被替换的字符串

replacement 表示替换字符串

Sets a string to replace and a replacement string. The string to replace is matched ignoring the case. The string to replace (1.9.4) and replacement string can contain variables. Several sub_filter directives can be specified on one configuration level (1.9.4). These directives are inherited from the previous level if and only if there are no sub_filter directives defined on the current level.

（2）sub_filter_last_modified语法

Syntax:	sub_filter_last_modified on \| off;
Default:	sub_filter_last_modified off;
Context:	http,server,location

This directive appeared in version 1.5.1.

语法解释：

sub_filter_last_modified on 表示允许在替换期间保留原始响应中的“Last-Modified”头字段，以便于响应缓存。

Allows preserving the “Last-Modified” header field from the original response during replacement to facilitate response caching.

By default, the header field is removed as contents of the response are modified during processing.

（3）sub_filter_once语法

Syntax:	sub_filter_once on \| off;
Default:	sub_filter_once on;
Context:	http,server,location

语法解释：

sub_filter_once on 表示只替换第一次匹配的字符串

Indicates whether to look for each string to replace once or repeatedly.

（4）sub_filter_types语法

Syntax:	sub_filter_types mime-type ...;
Default:	sub_filter_types text/html;
Context:	http,server,location

语法解释：

sub_filter_types text/html 表示替换文件类型，“*”表示匹配所有MIME类型

Enables string replacement in responses with the specified MIME types in addition to “text/html”. The special value “*” matches any MIME type (0.8.29).

3、sub_filter配置

（1）HTTP内容替换

（2）server1.html修改

4、验证sub_filter配置是否生效

（1）验证sub_filter配置是否生效

此时发现，只有第一个匹配的字符串被替换了；

原因：sub_filter_once默认配置为on

（2）显示关闭sub_filter_once配置

（3）验证sub_filter_once配置是否生效

sub_filter_once off配置生效，所有的匹配到的字符串全部被替换：