Message.Payload is always null for all messages. How do I get this data?

Question

It is returning the correct number of message, but the only fields that are populated are Id and ThreadId. Everything else is null

        var service = new GmailService(new BaseClientService.Initializer()
        {
            HttpClientInitializer = credential,
            ApplicationName = ApplicationName,
        });

        ListMessagesResponse response = service.Users.Messages.List(emailAddress).Execute();

        IList<Google.Apis.Gmail.v1.Data.Message> messages = response.Messages;

        Console.WriteLine("Messages:");
        if (messages != null && messages.Count > 0)
        {
            foreach (var message in messages)
            {
                Console.WriteLine("{0}", message.Payload.Body);
                Console.WriteLine();
            }
        }
        else
        {
            Console.WriteLine("No Messages found.");
        }

score 12 · Accepted Answer · edited Aug 15 '20 at 13:48

12

Messages.List() only returns message and thread ids. To retrieve message contents, you need to invoke Get() for each message you are interested in. Updated version of your foreach loop example:

foreach (var message in messages)
{
    Message m = service.Users.Messages.Get("me", message.Id).Execute();
    // m.Payload is populated now.
    foreach (var part in m.Payload.Parts)
    {
        byte[] data = Convert.FromBase64String(part.Body.Data);
        string decodedString = Encoding.UTF8.GetString(data);
        Console.WriteLine(decodedString);
    }
}

Note: You may need to run a string replace on the part.Body.Data string. See this post for instructions.

edited Aug 15 '20 at 13:48

Dan Beaulieu

19,406
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answered Apr 01 '16 at 21:09

Brandon Jewett-Hall

739
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You wouldn't know how to get the info from Message.Paylod.Body.Data to text would you? – Samuel Elrod Apr 01 '16 at 21:12
1

Updated code snippet with example of parsing mime parts. – Brandon Jewett-Hall Apr 01 '16 at 21:22
1

Yeah, thats what I've been trying; I get: The input is not a valid Base-64 string as it contains a non-base 64 character, – Samuel Elrod Apr 01 '16 at 21:23
1

Nevermind, it was a padding issue, fixed by this: switch (s.Length % 4) // Pad with trailing '='s { case 0: break; // No pad chars in this case case 2: s += "=="; break; // Two pad chars case 3: s += "="; break; // One pad char default: throw new System.Exception( "Illegal base64url string!"); } – Samuel Elrod Apr 01 '16 at 21:29
1

>Messages.List() only returns message and thread ids. \n Can you link to where this is documented please? – hermancain Jul 16 '17 at 18:41
@Brandon Jewett-Hall I went to Gmail API documentation and there is no mention on the messages.list method that explains I should use the Get() function. It says completely the opposite, it gives a field to choose for fields of message you would like to fetch and payload is included on that list although you can check on the api itself it wont work. I honestly think it is a bug on the API. https://developers.google.com/apis-explorer/#p/gmail/v1/gmail.users.messages.list – Murilo Nov 01 '17 at 20:13

Message.Payload is always null for all messages. How do I get this data?

1 Answers1