utils/sign_oss_mid/v1/sign.go

package v1

import (
	"context"
	"encoding/json"
	"errors"
	"net/url"
	"regexp"
	"strings"

	"gitea.drugeyes.vip/pharnexbase/utils/pkg/set"
	"github.com/aliyun/aliyun-oss-go-sdk/oss"
	"github.com/go-kratos/kratos/v2/middleware"
	"github.com/go-kratos/kratos/v2/transport"
)

type Signer struct {
	client *oss.Client
	bucketsWl []string
	expiredInSec int64 // 默认 7 天有效期
}

func NewSigner(client *oss.Client) *Signer {
	return &Signer{
		client: client,
		expiredInSec: 604800,
	}
}

type UrlInfo struct {
	Bucket   string
	Endpoint string
	Object   string
	FileName string
}

func (s *Signer) SetBucketsWhiteList(bucketsWl []string) *Signer {
	s.bucketsWl = bucketsWl
	return s
}

func (s *Signer) SetExpiredInSec(expiredInSec int64) *Signer {
	s.expiredInSec = expiredInSec
	return s
}

func (s *Signer) SignUrl() middleware.Middleware {
	return func(handler middleware.Handler) middleware.Handler {
		return func(ctx context.Context, req interface{}) (reply interface{}, err error) {
			reply, err = handler(ctx, req)
			if err != nil {
				return
			}

			if _, ok := transport.FromServerContext(ctx); ok {
				// 后置匹配 oss 地址，签名 url，替换输出
				var marshal []byte
				marshal, err = json.Marshal(reply)
				if err != nil {
					return
				}
				jsonStr := string(marshal)

				r := regexp.MustCompile("\"(https?://[-.a-z0-9]+\\.aliyuncs\\.com/[^\"\\\\]+)\\\\*\"")
				res := r.FindAllStringSubmatch(jsonStr, -1)
				for _, mu := range res {
					urlInfo, ue := GetUrlInfo(mu[1]) // url错误则不处理，用户中心不处理
					if ue == nil &&  !set.NewSetWithItems(s.bucketsWl...).Has(urlInfo.Bucket){
						var bucket *oss.Bucket
						bucket, err = s.client.Bucket(urlInfo.Bucket)
						if err != nil {
							return
						}

						// 生成用于下载的签名URL，并指定签名URL的有效时间。
						var surl string
						surl, err = bucket.SignURL(urlInfo.Object, oss.HTTPGet, s.expiredInSec)
						if err != nil {
							return
						}

						// 使用签名url替换原始url
						jsonStr = strings.Replace(jsonStr, mu[1], surl, -1)
					}
				}

				// 覆盖原始输出
				err = json.Unmarshal([]byte(jsonStr), reply)
				if err != nil {
					return
				}
			}
			return
		}
	}
}

func GetUrlInfo(ossUrl string) (*UrlInfo, error) {
	parse, err := url.Parse(ossUrl)
	if err != nil {
		return nil, err
	}

	hostInfo := strings.SplitN(parse.Host, ".", 2)
	if len(hostInfo) != 2 {
		return nil, errors.New("oss url error")
	}

	object := strings.TrimLeft(parse.Path, "/")
	if object == "" {
		return nil, errors.New("oss url error")
	}

	objectInfo := strings.Split(object, "/")
	if len(object) == 0 {
		return nil, errors.New("oss url error")
	}
	fileName := objectInfo[len(objectInfo)-1]

	return &UrlInfo{
		Bucket:   hostInfo[0],
		Endpoint: hostInfo[1],
		Object:   object,
		FileName: fileName,
	}, err
}