はここgolang

Question

に添付ファイル付きのメールを送信コードは次のとおりです。

package main 

import (
    "encoding/json" 
    "fmt" 
    "log" 
    "net/http" 
    "net/url" 
    "os" 
    "os/user" 
    "path/filepath" 

    "golang.org/x/net/context" 
    "golang.org/x/oauth2" 
    "golang.org/x/oauth2/google" 
    "google.golang.org/api/gmail/v1" 
    "encoding/base64" 
    "io/ioutil" 
) 

// getClient uses a Context and Config to retrieve a Token 
// then generate a Client. It returns the generated Client. 
func getClient(ctx context.Context, config *oauth2.Config, configFileName string) *http.Client { 
    cacheFile, err := tokenCacheFile(configFileName) 
    if err != nil { 
     log.Fatalf("Unable to get path to cached credential file. %v", err) 
    } 
    tok, err := tokenFromFile(cacheFile) 
    if err != nil { 
     tok = getTokenFromWeb(config) 
     saveToken(cacheFile, tok) 
    } 
    return config.Client(ctx, tok) 
} 

// getTokenFromWeb uses Config to request a Token. 
// It returns the retrieved Token. 
func getTokenFromWeb(config *oauth2.Config) *oauth2.Token { 
    authURL := config.AuthCodeURL("state-token", oauth2.AccessTypeOffline) 
    fmt.Printf("Go to the following link in your browser then type the " + 
    "authorization code: \n%v\n", authURL) 

    var code string 
    if _, err := fmt.Scan(&code); err != nil { 
     log.Fatalf("Unable to read authorization code %v", err) 
    } 

    tok, err := config.Exchange(oauth2.NoContext, code) 
    if err != nil { 
     log.Fatalf("Unable to retrieve token from web %v", err) 
    } 
    return tok 
} 

// tokenCacheFile generates credential file path/filename. 
// It returns the generated credential path/filename. 
func tokenCacheFile(filename string) (string, error) { 
    usr, err := user.Current() 
    if err != nil { 
     return "", err 
    } 
    tokenCacheDir := filepath.Join(usr.HomeDir, ".credentials") 
    os.MkdirAll(tokenCacheDir, 0700) 
    return filepath.Join(tokenCacheDir, 
     url.QueryEscape(filename)), err 
} 

// tokenFromFile retrieves a Token from a given file path. 
// It returns the retrieved Token and any read error encountered. 
func tokenFromFile(file string) (*oauth2.Token, error) { 
    f, err := os.Open(file) 
    if err != nil { 
     return nil, err 
    } 
    t := &oauth2.Token{} 
    err = json.NewDecoder(f).Decode(t) 
    defer f.Close() 
    return t, err 
} 

// saveToken uses a file path to create a file and store the 
// token in it. 
func saveToken(file string, token *oauth2.Token) { 
    fmt.Printf("Saving credential file to: %s\n", file) 
    f, err := os.Create(file) 
    if err != nil { 
     log.Fatalf("Unable to cache oauth token: %v", err) 
    } 
    defer f.Close() 
    json.NewEncoder(f).Encode(token) 
} 

func main() { 
    // Use oauth2.NoContext if there isn't a good context to pass in. 
    //ctx := context.TODO() 

    ctx := context.Background() 

    b, err := ioutil.ReadFile("client_secret.json") 
    if err != nil { 
     log.Fatalf("Unable to read client secret file: %v", err) 
    } 

    // If modifying these scopes, delete your previously saved credentials 
    // at ~/.credentials/gmail-go-quickstart.json 
    sendConfig, err := google.ConfigFromJSON(b, gmail.GmailSendScope) 
    if err != nil { 
     log.Fatalf("Unable to parse client secret file to config: %v", err) 
    } 
    sendClient := getClient(ctx, sendConfig, "send.json") 

    sendService, err := gmail.New(sendClient) 
    if err != nil { 
     log.Fatalf("Unable to retrieve gmail Client %v", err) 
    } 

    if err := SendEmail(ctx, sendService, "jane1988@gmail.com"); err != nil { 
     log.Fatalf("failed to send email: %v", err) 
    } 
} 

func SendEmail(ctx context.Context, svc *gmail.Service, email string) error { 

    header := make(map[string]string) 
    header["To"] = email 
    header["Subject"] = "hello there" 
    header["MIME-Version"] = "1.0" 
    header["Content-Type"] = `text/html; charset="utf-8"` 
    header["Content-Transfer-Encoding"] = "base64" 

    var msg string 
    for k, v := range header { 
     msg += fmt.Sprintf("%s: %s\n", k, v) 
    } 
    msg += "\n" + "Hello, Gmail!" 

    gmsg := gmail.Message{ 
     Raw: encodeWeb64String([]byte(msg)), 
    } 

    _, err := svc.Users.Messages.Send("me", &gmsg).Do() 
    return err 
} 

func encodeWeb64String(b []byte) string { 
    s := base64.URLEncoding.EncodeToString(b) 

    var i = len(s) - 1 
    for s[i] == '=' { 
     i-- 
    } 

    return s[0 : i + 1] 
} 

これは完璧に動作しますが、添付ファイルなし。メールにファイルを添付するにはどうしたらいいですか？

Answer 1

たぶん、あなたはmultipart/mixed（RFC 2046, Section 5.1.3）またはmultipart/alternative（RFC 2046, Section 5.1.4）にヘッダContent-Typeを変更しようとしてContent-Disposition: attachment; filename=<your file here.ext>の使用方法を確認することができます。