go 文件服务(读取须权限)

 1 package Network
 2 
 3 import (
 4     "encoding/base64"
 5     "encoding/json"
 6     "net/http"
 7     "os"
 8     "strings"
 9     "time"
10     "token"
11 )
12 
13 func getFile(w http.ResponseWriter, req *http.Request) {
14     var (
15         code     int         = Success
16         msg      string      = ""
17         result   interface{} = nil
18         httpCode int         = http.StatusOK
19     )
20     defer func() {
21         w.WriteHeader(httpCode)
22         if httpCode != http.StatusOK {
23             writeHTTPResult(w, code, msg, result)
24         }
25     }()
26     Token := req.FormValue("token")
27     user, ok := token.GetUser(Token)
28     if !ok {
29         httpCode = http.StatusForbidden
30         code = errNoPermission
31         msg = "token 无效"
32         return
33     }
34 
35     httpCode, fileInfo, base64FileName := Decode(req)
36 
37     if user.ID == fileInfo.ReceiverID || user.ID == fileInfo.SenderID {
38         httpCode, code, msg = WriteFile(w, req, fileInfo, base64FileName)
39         return
40     }
41 
42     code, msg = IsGroupID(fileInfo.ReceiverID)
43     if code != Success {
44         httpCode = http.StatusForbidden
45         if code == errInvalidID {
46             code = errNoPermission
47             msg = "you have no permission to get this file"
48         }
49         return
50     }
51 
52     code, msg = IsGroupMember(user.ID, fileInfo.ReceiverID)
53     if code != Success {
54         httpCode = http.StatusForbidden
55         if code == errInvalidID {
56             code = errNoPermission
57             msg = "you have no permission to get this file"
58         }
59         return
60     }
61 
62     httpCode, code, msg = WriteFile(w, req, fileInfo, base64FileName)
63     return
64 
65 }
66 func WriteFile(w http.ResponseWriter, req *http.Request, fileInfo *FileInfo, base64FileName string) (httpCode int, code int, msg string) {
67     file, err := os.Open(publicFileDir + "/" + fileInfo.FileType + "/" + base64FileName)
68     if err != nil {
69         httpCode = http.StatusNotFound
70         code = errFileNotFound
71         msg = err.Error()
72         return
73     }
74     defer file.Close()
75     w.Header().Set("Filename", fileInfo.FileName)
76     http.ServeContent(w, req, fileInfo.FileName, time.Time{}, file)
77     return http.StatusOK, Success, ""
78 }
79 
80 func Decode(req *http.Request) (httpCode int, fileInfo *FileInfo, base64FileName string) {
81     fileInfo = new(FileInfo)
82     URL := strings.Split(req.URL.Path, "/")
83     if len(URL) == 0 {
84         return http.StatusNotFound, nil, base64FileName
85     }
86     base64FileName = URL[len(URL)-1]
87     fileName, err := base64.StdEncoding.DecodeString(base64FileName)
88     if err != nil {
89         return http.StatusBadRequest, nil, base64FileName
90     }
91     err = json.Unmarshal(fileName, fileInfo)
92     if err != nil {
93         return http.StatusForbidden, nil, base64FileName
94     }
95     return http.StatusOK, fileInfo, base64FileName
96 }

getFile(server)

 1 func getFile(uri string, fileName string) error {
 2     resp, err := http.Get(uri)
 3     if err != nil {
 4         return err
 5     }
 6     defer resp.Body.Close()
 7     if resp.StatusCode != http.StatusOK {
 8         body, err := ioutil.ReadAll(resp.Body)
 9         if err != nil {
10             return err
11         }
12         return errors.New("statusCode:" + fmt.Sprint(resp.StatusCode) + "
" + string(body))
13     }
14     if fileName == "" {
15         if resp.Header["Filename"] != nil {
16             fileName = resp.Header["Filename"][0]
17         } else {
18             fileName = "notFound"
19         }
20     }
21     icon, err := os.Create(fileName)
22     if err != nil {
23         return err
24     }
25     _, err = io.Copy(icon, resp.Body)
26     if err != nil {
27         return err
28     }
29     logs.Print(resp.Header)
30     return nil
31 }

getFile(client)

这里由于http response的body完全是文件的二进制流，所以Filename要么是前端定义，要么是后端通过header返回

文件的url是一个base64编码的字符串，包含验证读取权限相关的所有信息和源文件名(服务器存文件时用的是base64编码作为文件名)