Sending RichText messages invalid_blocks error

[AlesDo]

I am facing a problem sending a message containing a rich text block. I get the error invalid_blocks. This happens using the following basic sample..

var slackWebApiClient = new SlackWebApiClient(Environment.GetEnvironmentVariable("SLACK_BOT_TOKEN"));

var richText = new RichText(
    new RichTextSection()
    {
        Elements = new List<RichTextElement>()
        {
            new TextElement()
            {
                Text = "Hello Rich Text"
            } 
        }
    });
var blocks = [richText];
var postMessageRequest = new PostMessageRequest()
{
    Channel = "<ValidChannelID>", 
    Text = "Hello From API",
    Blocks = blocks
};
var response =await slackWebApiClient.Chat.Post(postMessageRequest);

Am I doing something wrong or this is not supported?

[stoiveyp]

Morning @AlesDo - I'm at work right now so I can't replicate the issue for a little while.

when you look at the response object - is there a pointer returned with the error messager (like /blocks[0]...) that could help us narrow down the problem? The example you sent works in the Block Kit Builder so just seeing if there's more help coming from Slack until I can try and recreate it

[AlesDo]

Hi @stoiveyp !

Thanks for your quick reply.
The pointer returned is: must provide a string [json-pointer:/blocks/0/elements/0/elements/0/type].
It looks like it is a serialization issue that the type is not set for elements. it is set to null if I serialize the PostMessageReaquest using JsonConvert.SerializeObject.
Here is the output from serializing the request:

{
  "mrkdwn": false,
  "channel": "U06EE5LP7Q9",
  "blocks": [
    {
      "type": "rich_text",
      "block_id": "d2ff47786b264d7389c67a5695a587a0",
      "elements": [
        {
          "type": "rich_text_section",
          "elements": [
            {
              "text": "Hello World",
              "type": null
            }
          ]
        }
      ]
    }
  ],
  "text": "Hello from slack app!!!!!",
  "parse": "none"
}

[stoiveyp]

Oh! Yeah that's clearly wrong. I'll get a new test written and fix it once my working day is done. Apologies and thanks for raising it 👍

[stoiveyp]

This should now be fixed in v8.2.1 - please let me know 👍

[AlesDo]

Yes now it works. Thanks for the quick fix.
There is just one detail more. If you don't provide the BlockId on the rich text block it serializes to null which again cause an error. must provide a string [json-pointer:/blocks/0/block_id]. It should be omitted if it is not specified since it is an optional field https://api.slack.com/reference/block-kit/blocks#rich_fields

[stoiveyp]

v9.0.0 onward has Rich Text block_id set to optional