rclone authorize: Send and receive extra config options to fix oauth

Before this change any backends which required extra config in the
oauth phase (like the `region` for zoho) didn't work with `rclone
authorize`.

This change serializes the extra config and passes it to `rclone
authorize` and returns new config items to be set from rclone
authorize.

`rclone authorize` will still accept its previous configuration
parameters for use with old rclones.

Fixes #5178

fs/config/authorize.go

@@ -18,7 +18,7 @@ import (
 func Authorize(ctx context.Context, args []string, noAutoBrowser bool) error {
 	ctx = suppressConfirm(ctx)
 	switch len(args) {
-	case 1, 3:
+	case 1, 2, 3:
 	default:
 		return errors.Errorf("invalid number of arguments: %d", len(args))
 	}
@@ -40,7 +40,13 @@ func Authorize(ctx context.Context, args []string, noAutoBrowser bool) error {
 		inM[ConfigAuthNoBrowser] = "true"
 	}
 
-	if len(args) == 3 {
+	// Add extra parameters if supplied
+	if len(args) == 2 {
+		err := inM.Decode(args[1])
+		if err != nil {
+			return err
+		}
+	} else if len(args) == 3 {
 		inM[ConfigClientID] = args[1]
 		inM[ConfigClientSecret] = args[2]
 	}
@@ -52,13 +58,21 @@ func Authorize(ctx context.Context, args []string, noAutoBrowser bool) error {
 	outM := configmap.Simple{}
 	m.ClearSetters()
 	m.AddSetter(outM)
+	m.AddGetter(outM, configmap.PriorityNormal)
 
 	ri.Config(ctx, name, m)
 
-	// Print code if we are doing a manual auth
-	fmt.Printf("Paste the following into your remote machine --->\n%s\n<---End paste\n", outM["token"])
+	// Print the code for the user to paste
+	out := outM["token"]
 
-	fs.Debugf(nil, "Set parameters %q", outM)
+	// If received a config blob, then return one
+	if len(args) == 2 {
+		out, err = outM.Encode()
+		if err != nil {
+			return err
+		}
+	}
+	fmt.Printf("Paste the following into your remote machine --->\n%s\n<---End paste\n", out)
 
 	return nil
 }

lib/oauthutil/oauthutil.go

@@ -447,19 +447,46 @@ Execute the following on the machine with the web browser (same rclone
 version recommended):
 
 `)
-			if changed {
-				fmt.Printf("\trclone authorize %q -- %q %q\n", id, oauthConfig.ClientID, oauthConfig.ClientSecret)
+			// Find the configuration
+			ri, err := fs.Find(id)
+			if err != nil {
+				return errors.Wrap(err, "oauthutil authorize")
+			}
+			// Find the overridden options
+			inM := ri.Options.NonDefault(m)
+			delete(inM, config.ConfigToken) // delete token as we are refreshing it
+			for k, v := range inM {
+				fs.Debugf(nil, "sending %s = %q", k, v)
+			}
+			// Encode them into a string
+			mCopyString, err := inM.Encode()
+			if err != nil {
+				return errors.Wrap(err, "oauthutil authorize encode")
+			}
+			// Write what the user has to do
+			if len(mCopyString) > 0 {
+				fmt.Printf("\trclone authorize %q %q\n", id, mCopyString)
 			} else {
 				fmt.Printf("\trclone authorize %q\n", id)
 			}
 			fmt.Println("\nThen paste the result below:")
+			// Read the updates to the config
+			var outM configmap.Simple
+			for {
+				outM = configmap.Simple{}
 				code := config.ReadNonEmptyLine("result> ")
-			token := &oauth2.Token{}
-			err := json.Unmarshal([]byte(code), token)
-			if err != nil {
-				return err
+				err = outM.Decode(code)
+				if err == nil {
+					break
 				}
-			return PutToken(name, m, token, true)
+				fmt.Printf("Couldn't decode response - try again (make sure you are using a matching version of rclone on both sides: %v\n", err)
+			}
+			// Save the config updates
+			for k, v := range outM {
+				m.Set(k, v)
+				fs.Debugf(nil, "received %s = %q", k, v)
+			}
+			return nil
 		}
 	}