feat: add plugin - cache control (#810)

plugins/wasm-go/extensions/cache-control/READMD.md

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+# 功能说明
+`cache-control`插件实现了基于 URL 文件后缀来为请求的响应头部添加 `Expires` 和 `Cache-Control` 头部，从而方便浏览器对特定后缀的文件进行缓存，例如 `jpg`、`png` 等图片文件。
+
+# 配置字段
+
+| 名称      | 数据类型   | 填写要求                                                                                                | 默认值 | 描述                       |
+|---------|--------|-----------------------------------------------------------------------------------------------------|-|--------------------------|
+| suffix  | string | 选填，表示匹配的文件后缀名，例如 `jpg`、`png` 等。<br/>如果需要匹配多种后缀，需要用 `\|` 进行分割，例如 `png\|jpg`。<br/>如果不填写，表示匹配所有后缀      |   -  | 配置用于匹配的请求文件后缀            |
+| expires | string | 必填，表示缓存的最长时间。<br/>当填入的字符串为数字时，单位为秒，例如需要缓存1小时，需填写 3600。<br/>另外，还可以填写 epoch 或 max<br/>，与 nginx 中语义相同。 | - | 配置缓存的最大时间                |
+
+# 配置示例
+1. 缓存后缀为 `jpg`, `png`, `jpeg` 的文件，缓存时间为一小时
+```yaml
+suffix: jpg|png|jpeg
+expires: 3600
+```
+
+根据该配置，下列请求在访问时，将会在响应头中添加 `Expires` 和 `Cache-Control` 字段，且过期时间为 1 小时后。
+
+```bash
+curl http://example.com/test.png
+curl http://exmaple.com/test.jpg
+```
+2. 缓存所有文件，且缓存至最大时间 `“Thu, 31 Dec 2037 23:55:55 GMT”`
+```yaml
+expires: max 
+```
+

plugins/wasm-go/extensions/cache-control/VERSION

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+1.0.0

plugins/wasm-go/extensions/cache-control/go.mod

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+module github.com/alibaba/higress/plugins/wasm-go/extensions/cache-control
+
+go 1.18
+
+replace github.com/alibaba/higress/plugins/wasm-go => ../..
+
+require (
+	github.com/alibaba/higress/plugins/wasm-go v0.0.0
+	github.com/higress-group/proxy-wasm-go-sdk v0.0.0-20240226064518-b3dc4646a35a
+	github.com/tidwall/gjson v1.14.3
+)
+
+require (
+	github.com/google/uuid v1.3.0 // indirect
+	github.com/higress-group/nottinygc v0.0.0-20231101025119-e93c4c2f8520 // indirect
+	github.com/magefile/mage v1.14.0 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.0 // indirect
+	github.com/tidwall/resp v0.1.1 // indirect
+)

plugins/wasm-go/extensions/cache-control/main.go

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+package main
+
+import (
+	"github.com/alibaba/higress/plugins/wasm-go/pkg/wrapper"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm"
+	"github.com/higress-group/proxy-wasm-go-sdk/proxywasm/types"
+	"github.com/tidwall/gjson"
+	"net/http"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func main() {
+	wrapper.SetCtx(
+		"cache-control",
+		wrapper.ParseConfigBy(parseConfig),
+		wrapper.ProcessRequestHeadersBy(onHttpRequestHeaders),
+		wrapper.ProcessResponseHeadersBy(onHttpResponseHeaders),
+	)
+}
+
+type CacheControlConfig struct {
+	suffix  []string
+	expires string
+}
+
+func parseConfig(json gjson.Result, config *CacheControlConfig, log wrapper.Log) error {
+	suffix := json.Get("suffix").String()
+	if suffix != "" {
+		parts := strings.Split(suffix, "|")
+		config.suffix = parts
+	}
+
+	config.expires = json.Get("expires").String()
+
+	log.Infof("suffix: %q, expires: %s", config.suffix, config.expires)
+	return nil
+}
+
+func onHttpRequestHeaders(ctx wrapper.HttpContext, config CacheControlConfig, log wrapper.Log) types.Action {
+	path := ctx.Path()
+	if strings.Contains(path, "?") {
+		path = strings.Split(path, "?")[0]
+	}
+	ctx.SetContext("path", path)
+	log.Debugf("path: %s", path)
+
+	return types.ActionContinue
+}
+
+func onHttpResponseHeaders(ctx wrapper.HttpContext, config CacheControlConfig, log wrapper.Log) types.Action {
+	hit := false
+	if len(config.suffix) == 0 {
+		hit = true
+	} else {
+		path, ok := ctx.GetContext("path").(string)
+		if !ok {
+			log.Error("failed to get request path")
+			return types.ActionContinue
+		}
+
+		for _, part := range config.suffix {
+			if strings.HasSuffix(path, "."+part) {
+				hit = true
+				break
+			}
+		}
+	}
+	if hit {
+		if config.expires == "max" {
+			proxywasm.AddHttpResponseHeader("Expires", "Thu, 31 Dec 2037 23:55:55 GMT")
+			proxywasm.AddHttpResponseHeader("Cache-Control", "maxAge=315360000")
+		} else if config.expires == "epoch" {
+			proxywasm.AddHttpResponseHeader("Expires", "Thu, 01 Jan 1970 00:00:01 GMT")
+			proxywasm.AddHttpResponseHeader("Cache-Control", "no-cache")
+		} else {
+			maxAge, _ := strconv.ParseInt(config.expires, 10, 64)
+			currentTime := time.Now()
+			expireTime := currentTime.Add(time.Duration(maxAge) * time.Second)
+			proxywasm.AddHttpResponseHeader("Expires", expireTime.UTC().Format(http.TimeFormat))
+			proxywasm.AddHttpResponseHeader("Cache-Control", "maxAge="+strconv.FormatInt(maxAge, 10))
+		}
+	}
+	return types.ActionContinue
+}