# ngx\_http\_sub\_module

* [示例配置](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#example_configuration)
* [指令](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#directives)
  * [sub\_filter](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#sub_filter)
  * [sub\_filter\_last\_modified](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#sub_filter_last_modified)
  * [sub\_filter\_once](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#sub_filter_once)
  * [sub\_filter\_types](/nginx-docs/he-xin-gong-neng/http/ngx_http_sub_module.md#sub_filter_types)

`ngx_http_sub_module` 模块是一个过滤器，它通过替换指定的字符串来修改响应数据。

默认不构建此模块，可在构建时使用 `--with-http_sub_module` 配置参数启用。

## 示例配置 <a href="#example_configuration" id="example_configuration"></a>

```
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;
}
```

## 指令 <a href="#directives" id="directives"></a>

### sub\_filter

| -       | 说明                                    |
| ------- | ------------------------------------- |
| **语法**  | **sub\_filter** `string replacement`; |
| **默认**  | ——                                    |
| **上下文** | http、server、location                  |

设置要替换的字符串（`string`）和要替换成的字符串（`replacement`）。要替换的字符串匹配忽略大小写。要替换的字符串（1.9.4）和要替换成的字符串可以包含变量。可以在一个配置级别指定几个 `sub_filter` 指令（1.9.4）。当且仅当在当前级别上没有定义 `sub_filter` 指令时，这些指令才从上级继承。

### sub\_filter\_last\_modified

| -       | 说明                                             |
| ------- | ---------------------------------------------- |
| **语法**  | **sub\_filter\_last\_modified** `on` \| `off`; |
| **默认**  | sub\_filter\_last\_modified off;               |
| **上下文** | http、server、location                           |
| **提示**  | 该指令在 1.5.1 版本中出现                               |

允许在替换期间保留原始响应中的 **Last-Modified** 头字段，用于响应缓存。

默认情况下，在处理期间修改响应的内容时，将删除头字段。

### sub\_filter\_once

| -       | 说明                                   |
| ------- | ------------------------------------ |
| **语法**  | **sub\_filter\_once** `on` \| `off`; |
| **默认**  | sub\_filter\_once on;                |
| **上下文** | http、server、location                 |

只查找一次要替换的每个字符串或重复查找。

### sub\_filter\_types

| -       | 说明                                      |
| ------- | --------------------------------------- |
| **语法**  | **sub\_filter\_types** `mime-type ...`; |
| **默认**  | sub\_filter\_types text/html;           |
| **上下文** | http、server、location                    |

除了 **text/html** 之外，还指定在其他 MIME 类型的响应中启用字符串替换。特殊值 `*` 匹配任何 MIME 类型（0.8.29）。

## 原文档

* <http://nginx.org/en/docs/http/ngx_http_sub_module.html>


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