Golang Gmail Api

[reddragon09]

Expected Behavior

Run code in https://developers.google.com/gmail/api/quickstart/go success

Actual Behavior

I got error:
Go to the following link in your browser then type the authorization code:
https://accounts.google.com/o/oauth2/auth?access_type=offline&client_id=547117123835-tkhmlkohvj3rncvahj0h1o59vl4kgjpk.apps.googleusercontent.com&redirect_uri=urn%3Aietf%3Awg%3Aoauth%3A2.0%3Aoob&response_type=code&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fgmail.readonly&state=state-token
2019/10/09 18:19:30 Unable to read authorization code: EOF

Steps to Reproduce the Problem

1. Flow steps in https://developers.google.com/gmail/api/quickstart/go
2. Access link to get authCode: https://accounts.google.com/o/oauth2/auth?access_type=offline&client_id=547117123835-tkhmlkohvj3rncvahj0h1o59vl4kgjpk.apps.googleusercontent.com&redirect_uri=urn%3Aietf%3Awg%3Aoauth%3A2.0%3Aoob&response_type=code&scope=https%3A%2F%2Fwww.googleapis.com%2Fauth%2Fgmail.readonly&state=state-token
3. Run project

Specifications

• Go version go1.12.9
• Linux 18.04

[reddragon09]

My code

package mail_process

import (
	"encoding/json"
	"fmt"
	"github.com/astaxie/beego"
	"io/ioutil"
	"log"
	"net/http"
	"os"

	"golang.org/x/net/context"
	"golang.org/x/oauth2"
	"golang.org/x/oauth2/google"
	"google.golang.org/api/gmail/v1"
)

// MailsController operations for Mails
type CloneMailsController struct {
	beego.Controller
	//libs.Middleware
}

// URLMapping ...
func (c *CloneMailsController) URLMapping() {
	c.Mapping("Post", c.Post)
}

// CloneMail
// @Title CloneMail
// @Description CloneMail
// @Param	Authorization	header	string	false	"token"
// @Success 201 {int}
// @Failure 403 body is empty <br> 211 Variable is not json type <br> 217 Variable required <br> 303 Save data failures
//
// @router / [post]
func (c *CloneMailsController) CloneMail() {
	GetMail()
	c.Data["json"] = ""
	c.ServeJSON()
}

//Get mail from mail server
func GetMail() {
	b, err := ioutil.ReadFile("./storage/mail_process/credentials.json")
	if err != nil {
		log.Fatalf("Unable to read client secret file: %v", err)
	}

	// If modifying these scopes, delete your previously saved token.json.
	config, err := google.ConfigFromJSON(b, gmail.GmailReadonlyScope)
	if err != nil {
		log.Fatalf("Unable to parse client secret file to config: %v", err)
	}
	client := getClient(config)
	fmt.Println("---------------------------------------------------------------")
	fmt.Println(config)
	fmt.Println(client)
	srv, err := gmail.New(client)
	if err != nil {
		log.Fatalf("Unable to retrieve Gmail client: %v", err)
	}
	fmt.Println("+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++")
	fmt.Println(srv)
	user := "me"
	r, err := srv.Users.Labels.List(user).Do()
	if err != nil {
		log.Fatalf("Unable to retrieve labels: %v", err)
	}
	if len(r.Labels) == 0 {
		fmt.Println("No labels found.")
		return
	}
	fmt.Println("Labels:")
	for _, l := range r.Labels {
		fmt.Printf("- %s\n", l.Name)
	}
}

// Retrieve a token, saves the token, then returns the generated client.
func getClient(config *oauth2.Config) *http.Client {
	// The file token.json stores the user's access and refresh tokens, and is
	// created automatically when the authorization flow completes for the first
	// time.
	tokFile := "./storage/mail_process/token.json"
	tok, err := tokenFromFile(tokFile)
	if err != nil {
		tok = getTokenFromWeb(config)
		saveToken(tokFile, tok)
	}
	return config.Client(context.Background(), tok)
}

// Request a token from the web, then 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 authCode string = "4/rwFbig35HHvO6fps4tsup3wNP1ZW8onrmHxa1_kEq5BpYst0udZ8bkw"
	if _, err := fmt.Scan(&authCode); err != nil {
		log.Fatalf("Unable to read authorization code: %v", err)
	}

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

// Retrieves a token from a local file.
func tokenFromFile(file string) (*oauth2.Token, error) {
	f, err := os.Open(file)
	if err != nil {
		return nil, err
	}
	defer f.Close()
	tok := &oauth2.Token{}
	err = json.NewDecoder(f).Decode(tok)
	fmt.Println(f)
	fmt.Println(tok)
	return tok, err
}

// Saves a token to a file path.
func saveToken(path string, token *oauth2.Token) {
	fmt.Printf("Saving credential file to: %s\n", path)
	f, err := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
	if err != nil {
		log.Fatalf("Unable to cache oauth token: %v", err)
	}
	defer f.Close()
	json.NewEncoder(f).Encode(token)
}
```
`

[hi-Ernest]

you need add your account as test user of OAuth consent screen

[etiennepericat]

exact same problem here, even with test account properly saved, do you have any fix ?

[porridge]

From your source:

	var authCode string = "4/rwFbig35HHvO6fps4tsup3wNP1ZW8onrmHxa1_kEq5BpYst0udZ8bkw"

This variable must be empty for fmt.Scan to work as intended. But in the 2023 era even if you fix that, you'll hit another problem as described in #76 😉