即使使用 Etag，max-age：0、must-revalidate 和 no-cache，更改静态文件的 URL 仍然是 returns 304

Question

我正在尝试为我的 Spring 引导应用程序实现 Etag 功能，以便浏览器可以在服务器图像更改时更新图像缓存。

我通过 YAML 文件更改了 Spring 引导设置：

spring:
  jackson:
    serialization:
      WRITE_DATES_AS_TIMESTAMPS: false
  resources:
    static-locations: classpath:static/
    chain:
      strategy:
        content:
          enabled: true
    cache:
      cachecontrol:
        max-age: 0
        must-revalidate: true
        no-cache: true
  mvc:
    static-path-pattern: /resources/**

并添加了一个 ShallowEtagHeaderFilter bean：

@Configuration
public class MvcConfig implements WebMvcConfigurer {
    @Bean
    public ShallowEtagHeaderFilter shallowEtagHeaderFilter() {
        return new ShallowEtagHeaderFilter();
    }
}

第一个请求&响应header：

GET /resources/image/product/list/foo.png HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36
DNT: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,ko-KR;q=0.8,ko;q=0.7,vi;q=0.6
Cookie: _ga=GA1.1.134751806.1551948465; loginFlag=undefined; branchId=admin

HTTP/1.1 200
Last-Modified: Wed, 08 May 2019 05:17:32 GMT
Cache-Control: no-cache, must-revalidate
Accept-Ranges: bytes
ETag: "0b99ccc3070d4e65cd155b768a56f97e4"
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
X-Frame-Options: DENY
Content-Type: image/png
Content-Length: 101070
Date: Fri, 10 May 2019 08:03:37 GMT

第二次请求&响应header 不改变静态文件：

GET /resources/image/product/list/foo.png HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36
DNT: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,ko-KR;q=0.8,ko;q=0.7,vi;q=0.6
Cookie: _ga=GA1.1.134751806.1551948465; loginFlag=undefined; branchId=admin
If-None-Match: "0b99ccc3070d4e65cd155b768a56f97e4"
If-Modified-Since: Wed, 08 May 2019 05:17:32 GMT

HTTP/1.1 304
Last-Modified: Wed, 08 May 2019 05:17:32 GMT
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
X-Frame-Options: DENY
Date: Fri, 10 May 2019 08:05:32 GMT

对于第三个，我停止了 localhost 服务器，用另一个文件覆盖了 foo.png，重建了项目和运行服务器。我预计请求应该 return 更改后的图像文件，但状态为 304，图像与以前相同：

GET /resources/image/product/list/foo.png HTTP/1.1
Host: localhost:8080
Connection: keep-alive
Cache-Control: max-age=0
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36
DNT: 1
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.9,ko-KR;q=0.8,ko;q=0.7,vi;q=0.6
Cookie: _ga=GA1.1.134751806.1551948465; loginFlag=undefined; branchId=admin
If-None-Match: "0b99ccc3070d4e65cd155b768a56f97e4"
If-Modified-Since: Wed, 08 May 2019 05:17:32 GMT

HTTP/1.1 304
Last-Modified: Sun, 05 May 2019 19:08:52 GMT
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
X-Frame-Options: DENY
Date: Fri, 10 May 2019 08:09:32 GMT

我不知道如何在文件更改时刷新浏览器的缓存。我错过了什么？

Answer 1

看来设置没有问题。我没有通过 IDE(IntelliJ IDEA) 构建和运行项目，而是尝试 Gradle bootJar 和运行 jar 文件及其按预期工作。

即使使用 Etag，max-age：0、must-revalidate 和 no-cache，更改静态文件的 URL 仍然是 returns 304

Changed static file's URL still returns 304 even with Etag, max-age: 0, must-revalidate and no-cache

http

cache-control

browser-cache

http-headers

spring-boot