Slack.NetStandard

.NET Core NuGet package that helps with Slack interactions Available at https://www.nuget.org/packages/Slack.NetStandard

Create OAuth URL

using Slack.NetStandard.Auth;

var builder = new OAuthV2Builder("clientId")
{
    State = "stateGoesHere", 
    BotScope = "channels:read"
};
var redirectUri = builder.BuildUri();

Get OAuth Access Token from Code

using Slack.NetStandard.Auth;

var token = await OAuthV2Builder.Exchange(code,clientId,clientSecret);

Verify Incoming Request is from Slack

using Slack.NetStandard;

var verifier = new RequestVerifier(signingSecret);
var verified = verifier.Verify(request.Headers[RequestVerifier.SignatureHeaderName], long.Parse(request.Headers[RequestVerifier.TimestampHeaderName]), request.Body);

Receive/Respond to a slash command payload

var command = new SlashCommand(payloadText);

var message = new InteractionMessage();
message.Blocks.Add(new Section{Text = new PlainText("Only title is required")});
message.Blocks.Add(new Divider());
message.Send(command.ResponseUrl);

await command.Respond(message);

// or - if it's not from a slash command, any response url can use
await command.Response(responseUrl);

Building & sending a modal

var view = new View
{
    Type = "modal",
    Title = "Create New Story",
    Close = "Cancel",
    Submit = "Submit",
    Blocks = new IMessageBlock[]
    {
       new Section{Text = new PlainText("Only title is required")}
    }
};

var client = new SlackWebApiClient(accessToken);
var response = await client.View.Open(triggerId,view);

Sending a new message to a channel

var request = new PostMessageRequest {Channel = "C123456"};
request.Blocks.Add(new Section{Text = new PlainText("Hi There!")});

var client = new SlackWebApiClient("token");
await client.Chat.Post(request);

Parse Events API Body

using Slack.NetStandard.EventsApi;
using Slack.NetStandard.EventsApi.CallbackEvents;

var eventObject = JsonConvert.DeserializeObject<Event>(input.Body);

if (eventObject is EventCallback callback)
{
    switch(callback.Event)
    {
        case AppHomeOpened appHome:
            break;
        case GroupClose groupClose:
            break;

    }
}

Parse incoming text for entities (channels, users, links etc.)

var entities = TextParser.FindEntities("<@W123456|Steven>");
if(entities.First() is UserMention mention)
{
    var userId = mention.UserId //W123456
    var label = mention.Label //Steven
}

Socket Mode - getting to your payload

if(msg.Contains("envelope_id")) //If there's no envelope ID it's a Hello or Disconnect object
{
   var env = JsonConvert.DeserializeObject<Envelope>(msg);
   switch(env.Payload) {
     case SlashCommand command:
       //logic here
       break;
     case EventCallback evt: 
       //logic here
       break;
     case InteractionPayload payload:
       //logic here
       break;
   }
   var ack = new Acknowledge{EnvelopeId=env.EnvelopeId} //All messages must be acknowledged within a few seconds
   Send(ack);
}

For a .NET 3.1 client that helps with a lot of the Socket Mode plumbing, the SocketSample app is now available at Slack.NetStandard.AsyncEnumerable