apisix/doc/zh-cn/plugins/proxy-cache.md
2020-06-19 12:03:55 +08:00

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[English](../../plugins/proxy-cache.md)
# proxy-cache
代理缓存插件,该插件提供缓存后端响应数据的能力,它可以和其他插件一起使用。该插件支持基于磁盘的缓存,未来也会支持基于内存的缓存。目前可以根据响应码、请求 Method 来指定需要缓存的数据,另外也可以通过 no_cache 和 cache_bypass 配置更复杂的缓存策略。
基于磁盘的缓存需要注意:
1. 不能动态配置缓存的过期时间,只能通过后端服务响应头 Expires 或 Cache-Control 来设置过期时间,如果后端响应头中没有 Expires 或 Cache-Control那么 APISIX 将默认只缓存10秒钟
2. 如果后端服务不可用, APISIX 将返回502或504那么502或504将被缓存10秒钟
### 参数
|名称 |必须|类型|描述|
|------- |-----|------|------|
|cache_zone|是|string|指定使用哪个缓存区域不同的缓存区域可以配置不同的路径在conf/config.yaml文件中可以预定义使用的缓存区域|
|cache_key|是|array[string]|缓存key可以使用变量。例如["$host", "$uri", "-cache-id"]|
|cache_bypass|否|array[string]|是否跳过缓存检索,即不在缓存中查找数据,可以使用变量,需要注意当此参数的值不为空或非'0'时将会跳过缓存的检索。例如:["$arg_bypass"]|
|cache_method|否|array[string]|根据请求method决定是否需要缓存|
|cache_http_status|否|array[integer]|根据响应码决定是否需要缓存|
|hide_cache_headers|否|boolean|是否将 Expires 和 Cache-Control 响应头返回给客户端,默认为 false|
|no_cache|否|array[string]|是否缓存数据,可以使用变量,需要注意当此参数的值不为空或非'0'时将不会缓存数据。|
注:变量以$开头,也可以使用变量和字符串的结合,但是需要以数组的形式分开写,最终变量被解析后会和字符串拼接在一起。
### 示例
#### 启用插件
示例1为特定路由启用 `proxy-cache` 插件:
```shell
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
"plugins": {
"proxy-cache": {
"cache_zone": "disk_cache_one",
"cache_key": ["$uri", "-cache-id"],
"cache_bypass": ["$arg_bypass"],
"cache_method": ["GET"],
"cache_http_status": [200],
"hide_cache_headers": true,
"no_cache": ["$arg_test"]
}
},
"upstream": {
"nodes": {
"127.0.0.1:1999": 1
},
"type": "roundrobin"
},
"uri": "/hello"
}'
```
测试:
```shell
$ curl http://127.0.0.1:9080/hello -i
HTTP/1.1 200 OK
Content-Type: application/octet-stream
Content-Length: 6
Connection: keep-alive
Server: APISIX web server
Date: Tue, 03 Mar 2020 10:45:36 GMT
Last-Modified: Tue, 03 Mar 2020 10:36:38 GMT
Apisix-Cache-Status: MISS
hello
```
> http status 返回`200`并且响应头中包含`Apisix-Cache-Status`,表示该插件已启用。
示例2验证文件是否被缓存再次请求上边的地址
测试:
```shell
$ curl http://127.0.0.1:9080/hello -i
HTTP/1.1 200 OK
Content-Type: application/octet-stream
Content-Length: 6
Connection: keep-alive
Server: APISIX web server
Date: Tue, 03 Mar 2020 11:14:46 GMT
Last-Modified: Thu, 20 Feb 2020 14:21:41 GMT
Apisix-Cache-Status: HIT
hello
```
> 响应头 Apisix-Cache-Status 值变为了 HIT说明文件已经被缓存
示例3如何清理缓存的文件只需要指定请求的 method 为 PURGE
测试:
```shell
$ curl -i http://127.0.0.1:9080/hello -X PURGE
HTTP/1.1 200 OK
Date: Tue, 03 Mar 2020 11:17:35 GMT
Content-Type: text/plain
Transfer-Encoding: chunked
Connection: keep-alive
Server: APISIX web server
```
> 响应码为200即表示删除成功如果文件未找到将返回404
#### 禁用插件
移除插件配置中相应的 JSON 配置可立即禁用该插件,无需重启服务:
```shell
curl http://127.0.0.1:9080/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
{
"uri": "/hello",
"plugins": {},
"upstream": {
"type": "roundrobin",
"nodes": {
"127.0.0.1:1999": 1
}
}
}'
```
这时该插件已被禁用。