How can I forward a message in Go msgraph-sdk-go and include Cc and/or Bcc recipients?

Using the Go msgraph-sdk-go library, I am trying to forward a message. If I only have a "To" recipient, I can do it without issue but if I have "Cc" and/or "Bcc" recipients, I cannot get them added to the message.

The normal requestBody (users.NewItemMailFoldersItemMessagesItemForwardPostRequestBody()) used with the Forward().Post() function only has a SetToRecipients() function but does not have SetCcRecipients() or SetBccRecipients() functions.

I went through various attempts at working around this but the closest I have come still does not work. Instead of calling Forward().Post(), I call CreateForward().Post() instead, which creates a draft of the message, returning the message object (models.Messageable).

On that message object I am then able to call the SetToRecipients(), SetCcRecipients(), and/or SetBccRecipients() functions. I then call Patch() on the message to save the changes to the server, then I call Send() but I keep getting an error indicating there are no recipients defined.

The code I am working with is (simplified) as follows:

func forwardMessage(id string, toRecipients []models.Recipientable, ccRecipients []models.Recipientable, bccRecipients []models.Recipientable) (success bool) {
	var err error
	var message models.Messageable
	var requestBody = users.NewItemMailFoldersItemMessagesItemForwardPostRequestBody()

	message, err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(id).CreateForward().Post(context.Background(), requestBody, nil)
	if err != nil {
		fmt.Println(getOdataErrorV1(err).Error())
		return false
	}

	message.SetToRecipients(toRecipients)
	if len(ccRecipients) > 0 {
		message.SetCcRecipients(ccRecipients)
	}
	if len(bccRecipients) > 0 {
		message.SetBccRecipients(bccRecipients)
	}

	message, err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(*message.GetId()).Patch(context.Background(), message, nil)
	if err != nil {
		fmt.Println(getOdataErrorV1(err).Error())
		return false
	}

	err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(*message.GetId()).Send().Post(context.Background(), nil)
	if err != nil {
		fmt.Println(getOdataErrorV1(err).Error())
		return false
	}

	return true
}

Any help figuring this out would be appreciated!

After going back and forth and trying numerous different scenarios, I finally found the solution! I had to:

• Apply the To recipients to the requestBody BEFORE I called createForward.
• After I got the new (draft) message back from that call, I saved the new ID.
• Initialize a NEW message object and apply the Cc/Bcc recipients to that.
• Call Patch on the newID message, passing the re-initialized message object.
• Send the draft message.

The updated code is as follows:

func forwardMessage(id string, toRecipients []models.Recipientable, ccRecipients []models.Recipientable, bccRecipients []models.Recipientable) (success bool) {
    var err error
    var message models.Messageable
	var newID string
    var requestBody = users.NewItemMailFoldersItemMessagesItemForwardPostRequestBody()

	requestBody.SetToRecipients(toRecipients)

    message, err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(id).CreateForward().Post(context.Background(), requestBody, nil)
    if err != nil {
        fmt.Println(getOdataErrorV1(err).Error())
        return false
    }

	newID = *message.GetId()
		
	message = models.NewMessage()
    message.SetToRecipients(toRecipients)
    if len(ccRecipients) > 0 {
        message.SetCcRecipients(ccRecipients)
    }
    if len(bccRecipients) > 0 {
        message.SetBccRecipients(bccRecipients)
    }

    _, err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(newID).Patch(context.Background(), message, nil)
    if err != nil {
        fmt.Println(getOdataErrorV1(err).Error())
        return false
    }

    err = pClient.Users().ByUserId(cpMailbox).Messages().ByMessageId(newID).Send().Post(context.Background(), nil)
    if err != nil {
        fmt.Println(getOdataErrorV1(err).Error())
        return false
    }

    return true
}