SpringBoot 启用 GZIP 对响应进行压缩

系统管理员 2024-04-07 11:17 61阅读 0赞

![28da95348d55dbf53114d5dd9c4a5899.png][]

SpringBoot Web 应用默认是不启用响应数据的压缩，对大的文本类型的响应数据进行压缩是十分必要的，如 JSON, XML 等应用数据，甚至是 JS, CSS 等。

早先的 Web 应用基本是要配置一个叫做 `GzipFilter` 之类的东西，然后判断请求的 `Accept-Encoding` 是否含有 `gzip` , 再对需要的 `Content-Type` 响应类型的数据进行压缩。

在使用了 SpringBoot 之后，在碰到有压缩响应的需求的时候，第一件事情应该要想到是否能通过在 `application.properties` (或 application.yml) 配置就行。于是查阅 SpringBoot 2.7.x 的帮助文档 [Spring Boot Reference Document][] , 搜索关键字 `compression` ，翻几页就能找到 17.3.6. [Enable HTTP Response Compression][] , 介绍了三个配置项

1.  server.compression.enable=true (默认为 false, 不启用压缩)
2.  server.compression.min-response-size=2048 (默认至少 2K 字节以及以上大小的响应数据才被压缩, 要在网络带宽与 CPU 消耗上找到一个平衡)
3.  server.compression.mim-types=text/html,text/xml,text/plain,text/css,text/javascript,application/json,application/xml (默认压缩的响应类型)

再往下找到 [.A.11.Server Properties][] , 还有一个相关的选项

*  server.compression.exclude-user-agents= (默认为空，逗号分隔的 user-agent, 针对什么 user-agent 不启用压缩，可能给测试用的)

如果是 SpringBoot 1.2.x 的话，启用压缩的方法是不一样的，详情同样是参考官方的文档 [64.18 Enable HTTP response compression][]

这里我们再回到当前的 SpringBoot 2.7.x 版本，其实只要是 SpringBoot 1.3+ 的版本，唯一要做的就是配置

server.compression.enable=true

其他三个选项根据基本满足我们的日常要求了，或者按需稍加调节。

下面进行一些实战烟训，默认未配置 server.compression.enable 时，即默认为 false, 不启用响应压缩，写一个 controller 方法

@GetMapping(value = "/hello")
    public String hello(@RequestParam int length) {
        return StringUtils.repeat("0", length);
    }

<table> 
 <tbody> 
  <tr> 
   <td> <p>@&nbsp;GetMapping&nbsp;(&nbsp;value&nbsp;=&nbsp;"/hello"&nbsp;)</p> <p>public&nbsp;String&nbsp;hello&nbsp;(&nbsp;@&nbsp;RequestParam&nbsp;int&nbsp;length&nbsp;)&nbsp;{ </p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;StringUtils&nbsp;.&nbsp;repeat&nbsp;(&nbsp;"0"&nbsp;,&nbsp;length&nbsp;)&nbsp;;</p> <p>}</p> </td> 
  </tr> 
 </tbody> 
</table>

curl 测试

bash-3.2$ curl -I http://localhost:8080/hello?length=2047  HTTP/1.1 200  Content-Type: text/plain;charset=UTF-8  Content-Length: 2047  Date: Tue, 30 Aug 2022 03:01:53 GMT  bash-3.2$ curl -I http://localhost:8080/hello?length=2048  HTTP/1.1 200  Content-Type: text/plain;charset=UTF-8  Content-Length: 2048  Date: Tue, 30 Aug 2022 03:01:56 GMT  bash-3.2$ curl -I -H "Accept-Encoding:gzip" http://localhost:8080/hello?length=2049  HTTP/1.1 200  Content-Type: text/plain;charset=UTF-8  Content-Length: 2049  Date: Tue, 30 Aug 2022 03:02:20 GMT

怎么都不会对响应进行压缩，现在我们在 `application.properties` 中加上

server.compression.enabled = true

<table> 
 <tbody> 
  <tr> 
   <td> <p>server&nbsp;.&nbsp;compression&nbsp;.&nbsp;enabled&nbsp;=&nbsp;true</p> </td> 
  </tr> 
 </tbody> 
</table>

重新测试

bash-3.2$ curl -I -H "Accept-Encoding:gzip" http://localhost:8080/hello?length=2047  HTTP/1.1 200  Content-Type: text/plain;charset=UTF-8  Content-Length: 2047  Date: Tue, 30 Aug 2022 13:22:14 GMT  bash-3.2$ curl -I http://localhost:8080/hello?length=2048  HTTP/1.1 200  vary: accept-encoding  Content-Type: text/plain;charset=UTF-8  Content-Length: 2048  Date: Tue, 30 Aug 2022 13:22:16 GMT  bash-3.2$ curl -I -H "Accept-Encoding:gzip" http://localhost:8080/hello?length=2048  HTTP/1.1 200  vary: accept-encoding  Content-Encoding: gzip  Content-Type: text/plain;charset=UTF-8  Transfer-Encoding: chunked  Date: Tue, 30 Aug 2022 13:22:18 GMT

响应长度为 2048 及以上会采用压缩，并且这时不管有没有 `Accept-Encoding:gzip` 都会加上 `vary: accept-encoding` 用以区分不同的响应数据，像 Varnish 就要考虑 Accept-Encoding 作为 Key 的一部分缓存是否压缩的数据。

#### 关于 server.compression.mime-types ####

前面提过它的默认值是 text/html,text/xml,text/plain,text/css,text/javascript,application/json,application/xml, 即只对这些 Content-Type 类型的数据进行压缩，不该压缩的类型注意不要重复压缩，如 image/jpg, application/octet-stream 等.

text/plain 对 `Content-Type:text/plain;charset=UTF-8` 同样是适用的

不支持通配符配置，如不能用 text/\* 来涵盖所有以 text/ 开头的类型，像 test/html, test/xml, text/plain 等。必须一个个罗列出来

server.compression.mime-types 中的配置是区分大小写的，如

server.compression.mime-types=TEXT/PLAIN

<table> 
 <tbody> 
  <tr> 
   <td> <p>server&nbsp;.&nbsp;compression&nbsp;.&nbsp;mime&nbsp;-&nbsp;types&nbsp;=&nbsp;TEXT&nbsp;/&nbsp;PLAIN</p> </td> 
  </tr> 
 </tbody> 
</table>

对 Content-Type:text/plain 是不启作用的

bash-3.2$ curl -I -H "Accept-Encoding:gzip" http://localhost:8080/hello?length=2049  HTTP/1.1 200  Content-Type: text/plain;charset=UTF-8  Content-Length: 2049  Date: Tue, 30 Aug 2022 14:20:21 GMT

如果我们把 API 的 Content-Type 也设置为 `TEXT/PLAIN` 就能被压缩了

@GetMapping(value = "/hello")
    public ResponseEntity<String> hello(HttpServletResponse response, @RequestParam int length) {
        MultiValueMap<String, String> headers = new LinkedMultiValueMap<>();
        headers.add("Content-Type", "TEXT/PLAIN");
        return new ResponseEntity<>(StringUtils.repeat("0", length), headers,  HttpStatus.OK);
    }

<table> 
 <tbody> 
  <tr> 
   <td> <p>@&nbsp;GetMapping&nbsp;(&nbsp;value&nbsp;=&nbsp;"/hello"&nbsp;)</p> <p>public&nbsp;ResponseEntity&nbsp;&lt;&nbsp;String&nbsp;&gt;&nbsp;hello&nbsp;(&nbsp;HttpServletResponse&nbsp;response&nbsp;,&nbsp;@&nbsp;RequestParam&nbsp;int&nbsp;length&nbsp;)&nbsp;{ </p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;MultiValueMap&nbsp;&lt;&nbsp;String&nbsp;,&nbsp;String&nbsp;&gt;&nbsp;headers&nbsp;=&nbsp;new&nbsp;LinkedMultiValueMap&nbsp;&lt;&gt;&nbsp;(&nbsp;)&nbsp;;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;headers&nbsp;.&nbsp;add&nbsp;(&nbsp;"Content-Type"&nbsp;,&nbsp;"TEXT/PLAIN"&nbsp;)&nbsp;;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;new&nbsp;ResponseEntity&nbsp;&lt;&gt;&nbsp;(&nbsp;StringUtils&nbsp;.&nbsp;repeat&nbsp;(&nbsp;"0"&nbsp;,&nbsp;length&nbsp;)&nbsp;,&nbsp;headers&nbsp;,&nbsp;&nbsp;&nbsp;&nbsp;HttpStatus&nbsp;.&nbsp;OK&nbsp;)&nbsp;;</p> <p>}</p> </td> 
  </tr> 
 </tbody> 
</table>

bash-3.2$ curl -I -H "Accept-Encoding:gzip" http://localhost:8080/hello?length=2049  HTTP/1.1 200  vary: accept-encoding  Content-Encoding: gzip  Content-Type: TEXT/PLAIN  Transfer-Encoding: chunked  Date: Tue, 30 Aug 2022 14:22:20 GMT

注意在 Spring Web controller 方法中，对于标准的 Content-Type 是无法通过 @GetMapping 注解的 produces 和 HttpServletResponse 来改变的

@GetMapping(value = "/hello", produces = "TEXT/PLAIN")
    public String hello(HttpServletResponse response, @RequestParam int length) {
        response.setHeader("Content-Type", "TEXT/PLAIN");
        return StringUtils.repeat("0", length);
    }

<table> 
 <tbody> 
  <tr> 
   <td> <p>@&nbsp;GetMapping&nbsp;(&nbsp;value&nbsp;=&nbsp;"/hello"&nbsp;,&nbsp;produces&nbsp;=&nbsp;"TEXT/PLAIN"&nbsp;)</p> <p>public&nbsp;String&nbsp;hello&nbsp;(&nbsp;HttpServletResponse&nbsp;response&nbsp;,&nbsp;@&nbsp;RequestParam&nbsp;int&nbsp;length&nbsp;)&nbsp;{ </p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;response&nbsp;.&nbsp;setHeader&nbsp;(&nbsp;"Content-Type"&nbsp;,&nbsp;"TEXT/PLAIN"&nbsp;)&nbsp;;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;return&nbsp;StringUtils&nbsp;.&nbsp;repeat&nbsp;(&nbsp;"0"&nbsp;,&nbsp;length&nbsp;)&nbsp;;</p> <p>}</p> </td> 
  </tr> 
 </tbody> 
</table>

以上代码最终的 `Content-Type` 仍然为 `text/plain;charset=UTF-8`

#### 其他相关的内容 ####

SpringBoot 1.2.2 - <1.3 之间启用压缩的配置

server.tomcat.compression=on
    server.tomcat.compressableMimeTypes=application/json,application/xml,text/html,text/xml,text/plain,application/javascript,text/css

<table> 
 <tbody> 
  <tr> 
   <td> <p>server&nbsp;.&nbsp;tomcat&nbsp;.&nbsp;compression&nbsp;=&nbsp;on</p> <p>server&nbsp;.&nbsp;tomcat&nbsp;.&nbsp;compressableMimeTypes&nbsp;=&nbsp;application&nbsp;/&nbsp;json&nbsp;,&nbsp;application&nbsp;/&nbsp;xml&nbsp;,&nbsp;text&nbsp;/&nbsp;html&nbsp;,&nbsp;text&nbsp;/&nbsp;xml&nbsp;,&nbsp;text&nbsp;/&nbsp;plain&nbsp;,&nbsp;application&nbsp;/&nbsp;javascript&nbsp;,&nbsp;text&nbsp;/&nbsp;css</p> </td> 
  </tr> 
 </tbody> 
</table>

SpringBoot 1.2.2 之前，在使用 Tomcat 作为内嵌应用服务器时，通过 TomcatConnectorCustomizer

@Component
    public class TomcatCustomizer implements TomcatConnectorCustomizer {
    
      @Override
      public void customize(Connector connector) {
        connector.setProperty("compression", "on");
        // Add json and xml mime types, as they're not in the mimetype list by default
        connector.setProperty("compressableMimeType", "text/html,text/xml,text/plain,application/json,application/xml");
      }
    }

<table> 
 <tbody> 
  <tr> 
   <td> <p>@&nbsp;Component</p> <p>public&nbsp;class&nbsp;TomcatCustomizer&nbsp;implements&nbsp;TomcatConnectorCustomizer&nbsp;{ </p> <p>&nbsp;&nbsp;&nbsp;@&nbsp;Override</p> <p>&nbsp;&nbsp;&nbsp;public&nbsp;void&nbsp;customize&nbsp;(&nbsp;Connector&nbsp;connector&nbsp;)&nbsp;{ </p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;connector&nbsp;.&nbsp;setProperty&nbsp;(&nbsp;"compression"&nbsp;,&nbsp;"on"&nbsp;)&nbsp;;</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;// Add json and xml mime types, as they're not in the mimetype list by default</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;connector&nbsp;.&nbsp;setProperty&nbsp;(&nbsp;"compressableMimeType"&nbsp;,&nbsp;"text/html,text/xml,text/plain,application/json,application/xml"&nbsp;)&nbsp;;</p> <p>&nbsp;&nbsp;&nbsp;}</p> <p>}</p> </td> 
  </tr> 
 </tbody> 
</table>

Tomcat 本身可配置 server.xml 中的 connector 自动实现对响应数据的压缩，在 Apache Tomcat 10 Configuration Reference - [The HTTP Connector][] 一章中查找 `compression` 就能找到下面这几个属性

*  compression: off|on|force (默认为 off)
 *  compressibleMimeType: text/html,text/xml,text/plain,text/css,text/javascript,application/javascript,application/json,application/xml
 *  compressionMinSize: 2048
 *  noCompressionUserAgents: 默认为空，可使用正则表达式

HTTP/2 connector 也继承了以上几个属性配置

#### Apache HTTP Server 的压缩模块 ####

如果部署时在应用服务器(如 Tomcat) 前端配置了 Apache HTTP Server 的话，可以由 Apache 完成对数据的压缩，要使用到的模块是 `mod_defalte`

比如在 Debian 系的 OS 中 a2enmod deflate, 或在 httpd.conf 中用 `LoadModule deflate_module modules/mod_deflate.so` 启用。然后在 http.conf 或是应用的 .htaccess 文件中

AddOutputFilterByType DEFLATE text/plain
    AddOutputFilterByType DEFLATE text/html
    ......

<table> 
 <tbody> 
  <tr> 
   <td> <p>AddOutputFilterByType&nbsp;DEFLATE&nbsp;text&nbsp;/&nbsp;plain</p> <p>AddOutputFilterByType&nbsp;DEFLATE&nbsp;text&nbsp;/&nbsp;html</p> <p>.&nbsp;.&nbsp;.&nbsp;.&nbsp;.&nbsp;.</p> </td> 
  </tr> 
 </tbody> 
</table>

逐项加入要支持压缩的响应类型

具体使用方式请参照 [Apache Module mod\_deflate][Apache Module mod_deflate] 的文档。

[28da95348d55dbf53114d5dd9c4a5899.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/07/a8ae0ab6a23342879460eb37c5a68c65.png
[Spring Boot Reference Document]: https://docs.spring.io/spring-boot/docs/2.7.x/reference/htmlsingle/
[Enable HTTP Response Compression]: https://docs.spring.io/spring-boot/docs/2.7.x/reference/htmlsingle/#howto.webserver.enable-response-compression
[.A.11.Server Properties]: https://docs.spring.io/spring-boot/docs/2.7.x/reference/htmlsingle/#appendix.application-properties.server
[64.18 Enable HTTP response compression]: https://docs.spring.io/spring-boot/docs/1.2.x/reference/htmlsingle/#how-to-enable-http-response-compression
[The HTTP Connector]: https://tomcat.apache.org/tomcat-10.0-doc/config/http.html
[Apache Module mod_deflate]: https://httpd.apache.org/docs/2.4/mod/mod_deflate.html