go GCM加密解密 gin中间件加密解密，gin文件流处理

​要给已有的系统启用加密解密，目前推荐的是aes的gcm模式的加密和解密，在微服务如果向前有公共方法处理 读取数据和写返回数据，那么比较简单，修改以前的公共方法，但是这样本地调试平时肯定是明文，所以要加判断，如果以前的读数据和写数据是五花八门那就比较麻烦，在微服务体系里面一般有网关这个服务，所以加密和解密就放在网关服务，大致如下：

​

 常规的请求有GET，POST JSON， POST file,以及POST Form表单，返回一般是json 或者下载文件流，所以我们需要截获请求流和返回流，收到请求流解密数据 然后重新写入到请求流，收到返回流加密数据，重写返回流。

首先来看aes加密和解密程序aes.go

package aes

import (
    "crypto/aes"
    "crypto/cipher"
    "crypto/md5"
    "crypto/rand"
    "encoding/base64"
    "encoding/hex"
    "errors"
    "io"
)

//加密字符串
func GcmEncrypt(key, plaintext string) (string, error) {
    if len(key) != 32 && len(key) != 24 && len(key) != 16 {
        return "", errors.New("the length of key is error")
    }

    if len(plaintext) < 1 {
        return "", errors.New("plaintext is null")
    }

    keyByte := []byte(key)
    plainByte:=[]byte(plaintext)

    block, err := aes.NewCipher(keyByte)
    if err != nil {
        return "", err
    }

    aesGcm, err := cipher.NewGCM(block)
    if err != nil {
        return "", err
    }

    nonce := make([]byte, 12)
    if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
        return "", err
    }

    seal := aesGcm.Seal(nonce, nonce, plainByte, nil)
    return base64.URLEncoding.EncodeToString(seal), nil
}

//解密字符串
func GcmDecrypt(key, cipherText string) (string, error) {
    if len(key) != 32 && len(key) != 24 && len(key) != 16 {
        return "", errors.New("the length of key is error")
    }

    if len(cipherText) < 1 {
        return "", errors.New("cipherText is null")
    }

    cipherByte, err := base64.URLEncoding.DecodeString(cipherText)
    if err != nil {
        return "", err
    }

    if len(cipherByte) < 12 {
        return "", errors.New("cipherByte is error")
    }

    nonce, cipherByte := cipherByte[:12], cipherByte[12:]

    keyByte := []byte(key)
    block, err := aes.NewCipher(keyByte)
    if err != nil {
        return "", err
    }

    aesGcm, err := cipher.NewGCM(block)
    if err != nil {
        return "", err
    }

    plainByte, err := aesGcm.Open(nil, nonce, cipherByte, nil)
    if err != nil {
        return "", err
    }

    return string(plainByte), nil
}

//生成32位md5字串
func GetAesKey(s string) string {
        h := md5.New()
        h.Write([]byte(s))
        return hex.EncodeToString(h.Sum(nil))

}

再来看看网关转发程序proxy.go

package middleware

import (
    "fmt"
    "github.com/gin-gonic/gin"
    "github.com/valyala/fasthttp"
    "io/ioutil"
    "runtime/debug"
    "time"
)

var fastClient *fasthttp.Client

func init() {
    fastClient = &fasthttp.Client{}
    fastClient.MaxIdemponentCallAttempts = 1
    fastClient.ReadTimeout = time.Second * 60
}

func GetHttpClient() *fasthttp.Client {
    return fastClient
}
func GateWay() gin.HandlerFunc {
    return func(c *gin.Context) {
        defer func() {
            if e := recover(); e != nil {
                stack := debug.Stack()
                log("GateWay Recovery: err:%v, stack:%v", e, string(stack))
            }
        }()

        err := Forward(c)
        if err != nil {
            response(c, 9999, "系统错误", err.Error())
        }
        return
    }
}

func Forward(ctx *gin.Context) error {
    req := &fasthttp.Request{}

    //请求-获取服务地址
    host := "http://localhost:8000/" + ctx.Request.URL.String()
    //请求-url
    req.SetRequestURI(host)

    //请求-header
    for k, v := range ctx.Request.Header {
        req.Header.Set(k, v[0])
    }

    //请求-body
    data, err := ioutil.ReadAll(ctx.Request.Body)
    if err != nil {
        log("Forward err:%v", err)
        return fmt.Errorf("系统错误")
    }
    req.SetBody(data)

    //请求-方法
    req.Header.SetMethod(ctx.Request.Method)

    //请求-发送
    resp := &fasthttp.Response{}

    //请求-新增调用链
    /*
        err = opentracing.GlobalTracer().Inject(
            opentracing.SpanFromContext(ctx.Request.Context()).Context(),
            opentracing.TextMap,
            HTTPHeadersCarrier{&req.Header},
        )
    */

    err = GetHttpClient().Do(req, resp)
    if err != nil {
        log("Forward GetHttpClient DO err:%v", err)
        return fmt.Errorf("系统错误")
    }

    //请求-响应
    ContentType := fmt.Sprintf("%s", resp.Header.Peek("Content-Type"))
    ctx.Data(resp.StatusCode(), ContentType, resp.Body())

    return nil
}

type HTTPHeadersCarrier struct {
    *fasthttp.RequestHeader
}

func (c HTTPHeadersCarrier) Set(key, val string) {
    h := c.RequestHeader
    h.Add(key, val)
}

最后来看一下gin的中间件crypto.go

package middleware

import (
    "bytes"
    "demo/aes"
    "encoding/json"
    "errors"
    "fmt"
    "github.com/gin-gonic/gin"
    "io"
    "io/ioutil"
    "mime"
    "mime/multipart"
    "net/url"
    "runtime/debug"
    "strconv"
    "strings"
)

type aesWriter struct {
    gin.ResponseWriter
    body *bytes.Buffer
}

func (w *aesWriter) Write(b []byte) (int, error) {
    return w.body.Write(b)
}

func (w *aesWriter) WriteString(s string) (int, error) {
    return w.body.WriteString(s)
}

//只有经过token 验证的才会加密 和解密
//handleFile 表示是否处理上传文件， 默认网关不处理上传文件的encryptString数据， 如果处理会导致具体服务无法接收到具体参数
func AesGcmDecrypt() gin.HandlerFunc {
    return func(c *gin.Context) {
        defer func() {
            if e := recover(); e != nil {
                stack := debug.Stack()
                log("AesGcmDecrypt Recovery: err:%v, stack:%v", e, string(stack))
            }
        }()

        if c.Request.Method == "OPTIONS" {
            c.Next()
        } else {
            md5key := aes.GetAesKey("gavin12345678")
            log("AesGcmDecrypt start url:%s  ,md5key:%s, Method:%s, Header:%+v", c.Request.URL.String(), md5key, c.Request.Method, c.Request.Header)
            handleAes(c, md5key)
        }
    }
}

//请求和返回都加密 解密
func handleAes(c *gin.Context, md5key string) {
    contentType := c.Request.Header.Get("Content-Type")
    isJsonRequest := strings.Contains(contentType, "application/json")
    isFileRequest := strings.Contains(contentType, "multipart/form-data")
    isFormUrl := strings.Contains(contentType, "application/x-www-form-urlencoded")

    if c.Request.Method == "GET" {
        err := parseQuery(c, md5key)
        if err != nil {
            log("handleAes parseQuery  err:%v", err)
            //这里输出应该密文 一旦加密解密调试好 这里就不会走进来
            response(c, 2001, "系统错误", err.Error())
            return
        }
    } else if isJsonRequest {
        err := parseJson(c, md5key)
        if err != nil {
            log("handleAes parseJson err:%v", err)
            //这里输出应该密文 一旦加密解密调试好 这里就不会走进来
            response(c, 2001, "系统错误", err.Error())
            return
        }
    } else if isFormUrl {
        err := parseForm(c, md5key)
        if err != nil {
            log("handleAes parseForm err:%v", err)
            //这里输出应该密文 一旦加密解密调试好 这里就不会走进来
            response(c, 2001, "系统错误", err.Error())
            return
        }
    } else if isFileRequest {
        err := parseFile(c, md5key)
        if err != nil {
            log("handleAes parseFile err:%v", err)
            //这里输出应该密文 一旦加密解密调试好 这里就不会走进来
            response(c, 2001, "系统错误", err.Error())
            return
        }
    }

    ///截取 response body
    oldWriter := c.Writer
    blw := &aesWriter{body: bytes.NewBufferString(""), ResponseWriter: c.Writer}
    c.Writer = blw

    // 走流程
    c.Next()

    ///获取返回数据
    responseByte := blw.body.Bytes()

    //日志
    c.Writer = oldWriter
    //如果返回的不是json格式 那么直接返回,应为文件下载之类的不应该加密
    if !isJsonResponse(c) {
        _, _ = c.Writer.Write(responseByte)
        return
    }

    ///加密
    encryptStr, err := aes.GcmEncrypt(md5key, string(responseByte))
    if err != nil {
        log("handleAes GcmEncrypt err:%v", err)
        response(c, 2001, "系统错误", err.Error())
        return
    }

    _, _ = c.Writer.WriteString(encryptStr)
}

//处理json
func parseJson(c *gin.Context, md5key string) error {
    //读取数据 body处理
    payload, err := c.GetRawData()
    if err != nil {
        return err
    }

    ///解密body数据 请求的json是{"encryptString":{value}} value含有gcm的12字节nonce,实际长度大于32
    if payload != nil && len(payload) > 20 {
        var jsonData encryptJson
        log("AesGcmDecrypt  parseJson url:%s md5key:%s,old data:%s,", c.Request.URL.String(), md5key, string(payload))

        err := json.Unmarshal(payload, &jsonData)
        if err != nil {
            log("AesGcmDecrypt parseJson Unmarshal err:%v", err)
            return err
        }

        payloadText := jsonData.EncryptString
        if len(payloadText) > 0 {
            payloadText, err = aes.GcmDecrypt(md5key, payloadText)
            if err != nil {
                log("AesGcmDecrypt parseJson GcmDecryptByte err:%v", err)
                return err
            }
            payload = []byte(payloadText)
            log("AesGcmDecrypt  parseJson url:%s md5key:%s,encryptString:%s,decrypt data:%s", c.Request.URL.String(), md5key, jsonData.EncryptString, payloadText)
        }
    }

    c.Request.Body = ioutil.NopCloser(bytes.NewBuffer(payload))

    return nil
}

func parseForm(c *gin.Context, md5key string) error {
    //读取数据 body处理
    payload, err := c.GetRawData()
    if err != nil {
        return err
    }

    ///解密body数据 请求的json是"encryptString= value含有gcm的12字节nonce,实际长度大于32
    if payload != nil && len(payload) > 20 {
        var jsonData encryptJson
        log("AesGcmDecrypt  parseForm url:%s md5key:%s,old data:%s,", c.Request.URL.String(), md5key, string(payload))

        values, err := url.ParseQuery(string(payload))
        if err != nil {
            log("AesGcmDecrypt parseForm ParseQuery err:%v", err)
            return err
        }

        payloadText := values.Get("encryptString")
        if len(payloadText) > 0 {
            mapData, err := gcmDecryptString(md5key, payloadText)
            if err != nil {
                log("AesGcmDecrypt parseForm gcmDecryptString err:%v", err)
                return err
            }

            for k, v := range mapData {
                values.Add(k, getStr(v))
            }

            formData := values.Encode()
            log("AesGcmDecrypt  parseForm url:%s md5key:%s,encryptString:%s,decrypt data:%s", c.Request.URL.String(), md5key, jsonData.EncryptString, formData)
            payload = []byte(formData)
        }
    }

    c.Request.Body = ioutil.NopCloser(bytes.NewBuffer(payload))

    return nil
}

//处理get url的解密
func parseQuery(c *gin.Context, md5Key string) error {
    encryptString := c.Query("encryptString")
    log("AesGcmDecrypt parseQuery url:%s, md5key:%s, encryptString:%s", c.Request.URL.String(), md5Key, encryptString)

    if len(encryptString) < 1 {
        return nil
    }

    queryData, err := gcmDecryptString(md5Key, encryptString)
    if err != nil {
        return err
    }

    var args []string
    var logs []string
    for k, v := range queryData {
        val := getStr(v)
        args = append(args, fmt.Sprintf("%s=%s", k, url.QueryEscape(val)))
        logs = append(logs, fmt.Sprintf("%s=%s", k, val))
    }

    log("AesGcmDecrypt parseQuery  url:%s, md5key:%s, encryptString:%s, decrypt data:%s", c.Request.URL.String(), md5Key, encryptString, strings.Join(logs, "&"))
    c.Request.URL.RawQuery = strings.Join(args, "&")
    return nil
}

func parseFile(c *gin.Context, md5Key string) error {
    contentType := c.Request.Header.Get("Content-Type")
    _, params, _ := mime.ParseMediaType(contentType)
    boundary, ok := params["boundary"]
    if !ok {
        return errors.New("no multipart boundary param in Content-Type")
    }

    //准备重写数据
    bodyBuf := &bytes.Buffer{}
    wr := multipart.NewWriter(bodyBuf)
    mr := multipart.NewReader(c.Request.Body, boundary)
    for {
        p, err := mr.NextPart() //p的类型为Part
        if err == io.EOF {
            break
        }

        if err != nil {
            log("NextPart err:%v", err)
            break
        }

        fileByte, err := ioutil.ReadAll(p)
        if err != nil {
            log("ReadAll err:%v", err)
            break
        }

        pName := p.FormName()
        fileName := p.FileName()
        if len(fileName) < 1 {
            if pName == "encryptString" {
                formData, err := gcmDecryptString(md5Key, string(fileByte))
                if err != nil {
                    log("AesGcmDecrypt writeFile gcmDecryptString err:%v", err)
                    break
                }

                for k, v := range formData {
                    val := getStr(v)
                    err = wr.WriteField(k, val)
                    if err != nil {
                        log("AesGcmDecrypt writeFile WriteField :%s=%s, err:%v", k, val, err)
                        break
                    }
                }
            } else {
                wr.WriteField(pName, string(fileByte))
            }
        } else {
            tmp, err := wr.CreateFormFile(pName, fileName)
            if err != nil {
                log("AesGcmDecrypt parseFile CreateFormFile err:%v", err)
                continue
            }
            tmp.Write(fileByte)
        }
    }

    //写结尾标志
    _ = wr.Close()
    c.Request.Header.Set("Content-Type", wr.FormDataContentType())
    c.Request.Body = ioutil.NopCloser(bytes.NewBuffer(bodyBuf.Bytes()))

    return nil
}

func gcmDecryptString(md5Key, encryptString string) (map[string]interface{}, error) {
    formData := make(map[string]interface{}, 0)
    if len(encryptString) < 1 {
        return formData, nil
    }

    plaintext, err := aes.GcmDecrypt(md5Key, encryptString)
    if err != nil {
        return formData, err
    }

    if len(plaintext) < 3 {
        //plaintext 应该是json 串 {}
        return formData, nil
    }

    err = json.Unmarshal([]byte(plaintext), &formData)
    if err != nil {
        return formData, err
    }

    return formData, nil
}

func isJsonResponse(c *gin.Context) bool {
    contentType := c.Writer.Header().Get("Content-Type")
    return strings.Contains(contentType, "application/json")
}

func getStr(v interface{}) string {
    val := ""
    switch v.(type) {
    case float64:
        //tmp, _ := decimal.NewFromString(fmt.Sprintf("%.10f", v))
        fl, _ := v.(float64)
        val = strconv.FormatFloat(fl, 'f', -1, 64)
    default:
        val = fmt.Sprintf("%v", v)
    }
    return val
}

type encryptJson struct {
    EncryptString string `json:"encryptString"`
}

func log(format string, arg ...interface{}) {
    fmt.Print(fmt.Sprintf(format, arg...))
}
func response(c *gin.Context, code int, msg string, data interface{}) {
    mapData := make(map[string]interface{}, 0)
    mapData["code"] = code
    mapData["msg"] = msg
    mapData["data"] = data
    c.JSON(200, data)
    c.Abort()
    return
}

最后我们来写一个demo程序main.go

package main

import (
    "demo/middleware"
    "fmt"
    "github.com/gin-gonic/gin"
    "os"
)

func main() {
    go func() {
        gateway := gin.Default()
        gateway.Use(middleware.AesGcmDecrypt())
        gateway.Use(middleware.GateWay())
        gateway.Run(":8080")
    }()

    // 1.创建路由
    r := gin.Default()
    r.Use(middleware.Logger())

    r.GET("/", func(c *gin.Context) {
        c.Writer.WriteString("pong")
    })

    r.GET("/demo", func(c *gin.Context) {
        req := ReqObj{}
        err := c.ShouldBindQuery(&req)
        if err != nil {
            fmt.Print(err)
        }
        response(c, 200, "ok", req)
    })

    r.POST("/test", func(c *gin.Context) {
        req := ReqObj{}
        err := c.ShouldBind(&req)
        if err != nil {
            fmt.Print(err)
        }
        response(c, 200, "ok", req)
    })

    r.POST("/form", func(c *gin.Context) {
        req := ReqObj{}
        err := c.ShouldBind(&req)
        if err != nil {
            fmt.Print(err)
        }
        response(c, 200, "ok", req)
    })

    r.POST("/upload", func(c *gin.Context) {
        file, err := c.FormFile("file")
        if err != nil {
            fmt.Print(err)
        }
        folder := c.Request.FormValue("folder")
        tmp, _ := os.Getwd()
        filePath := tmp + "/upload/" + folder + "/" + file.Filename
        c.SaveUploadedFile(file, filePath)
    })

    r.Run(":8000")
}

type ReqObj struct {
    Name       string `json:"name" form:"name"`
    Age        int64  `json:"age"  form:"age"`
    UpdateTime int64  `json:"update_time"  form:"update_time"`
    Folder     string `json:"folder"  form:"folder"`
}

func response(c *gin.Context, code int, msg string, data interface{}) {
    mapData := make(map[string]interface{}, 0)
    mapData["code"] = code
    mapData["msg"] = msg
    mapData["data"] = data
    c.JSON(200, data)
    c.Abort()
    return
}

 来让我们一次验证一下运行结果：

1.GET请求

  2.看看post json

 3验证postform

  最后来看一下文件上传：

下载地址：https://github.com/dz45693/gindemo.git