/
main.go
129 lines (112 loc) · 3.14 KB
/
main.go
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package main
import (
"encoding/base64"
"encoding/json"
"io/ioutil"
"log"
"net/http"
"net/url"
"os"
"path/filepath"
"strings"
"time"
conflib "github.com/yyoshiki41/go-gmail-drafts/lib"
"golang.org/x/net/context"
"golang.org/x/oauth2"
"golang.org/x/text/encoding/japanese"
"golang.org/x/text/transform"
"google.golang.org/api/gmail/v1"
)
// 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) *http.Client {
cacheFile := filepath.Join("./.credentials", url.QueryEscape("gmail_token.json"))
token, err := tokenFromFile(cacheFile)
if err != nil {
log.Fatalf("Unable to retrieve token from cached credential file. %v", err)
}
return config.Client(ctx, token)
}
// 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
}
// loadBodyFile returns mail body in the json template.
func loadBodyFile() (map[string]interface{}, error) {
c := make(map[string]interface{})
f, err := ioutil.ReadFile("./config/draft_tmpl.json")
if err != nil {
return c, err
}
json.Unmarshal(f, &c)
return c, nil
}
// createDraftsStr returns to, subject and message for gmail.
func createDraftsStr(draftMap map[string]interface{}) (string, string, string) {
// mail to
toStr := "to: "
if to, ok := draftMap["to"].(string); ok {
toStr += to
}
toStr += "\n"
// subject
subStr := "subject: "
if subject, ok := draftMap["subject"].(string); ok {
subStr += subject
}
subStr += "\n"
t := time.Now()
subStr = strings.Replace(subStr, "{{today}}", t.Format("01/02"), -1)
// message
msgStr := "\n"
if message, ok := draftMap["message"].(string); ok {
msgStr += message
}
msgStr = strings.Replace(msgStr, "{{today}}", t.Format("01/02"), -1)
return toStr, subStr, msgStr
}
// Convert UTF-8 to ISO2022JP
func toISO2022JP(str string) ([]byte, error) {
reader := strings.NewReader(str)
transformer := japanese.ISO2022JP.NewEncoder()
return ioutil.ReadAll(transform.NewReader(reader, transformer))
}
func main() {
ctx := context.Background()
config, err := conflib.CreateGmailConfig()
if err != nil {
log.Fatalf("Unable to parse client secret file to config: %v", err)
}
client := getClient(ctx, config)
srv, err := gmail.New(client)
if err != nil {
log.Fatalf("Unable to retrieve gmail Client %v", err)
}
_ = srv
draftMap, err := loadBodyFile()
if err != nil {
log.Fatalf("Unable to parse draft template file to map structure: %v", err)
}
toStr, subStr, msgStr := createDraftsStr(draftMap)
header, _ := toISO2022JP(toStr + subStr)
msg := []byte(msgStr)
bodyBytes := append(header, msg...)
message := gmail.Message{}
message.Raw = base64.URLEncoding.EncodeToString(bodyBytes)
user := "me"
draft := gmail.Draft{
Message: &message,
}
_, err = srv.Users.Drafts.Create(user, &draft).Do()
if err != nil {
log.Fatalf("Unable to create drafts: %v", err)
}
}