DiscordWebhook.cs

using AzureDevOpsDiscord.Models.Discord;
using RestSharp;

namespace AzureDevOpsDiscord
{
    public static class DiscordWebhook
    {
        // the post to Discord will reject the hook unless it includes valid User-Agent
        static readonly string USER_AGENT = "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.103 Safari/537.36";

        // https://discordapp.com/developers/docs/resources/channel#embed-limits
        static readonly int MAX_DESCRIPTION_LENGTH = 2048;


        static readonly string? DISCORD_ID = Environment.GetEnvironmentVariable("discord_id");
        static readonly string? DISCORD_TOKEN = Environment.GetEnvironmentVariable("discord_token");

        public static async Task<bool> SendDiscordWebhook(string title, string? url, string description, string? author, int color)
        {
            if (string.IsNullOrEmpty(DISCORD_ID) || string.IsNullOrEmpty(DISCORD_TOKEN))
            {
                Console.WriteLine("Discord id or token is not defined in the lambda enviroment variable.");
                return false;
            }

            var client = new RestClient($"https://discordapp.com/api/webhooks/{DISCORD_ID}/{DISCORD_TOKEN}");
            var request = new RestRequest();
            request.AddHeader("User-Agent", USER_AGENT);
            request.AddJsonBody(ConstructBodyString(title, url, description, author, color));
            var response = await client.ExecutePostAsync(request);

            if (response.IsSuccessful)
            {
                client.Dispose();
                return true;
            }
            else
            {
                Console.WriteLine($"{response.StatusCode} {response.Content}");
                Console.WriteLine($"{response.ErrorMessage} {response.ErrorException}");
                client.Dispose();
                return false;
            }
        }

        /**
		  * {
		  *   "username": "JIRA",
		  *   "avatar_url": "https://wiki.jenkins-ci.org/download/attachments/2916393/headshot.png",
		  *   "embeds": [{
		  *     "title": "This is the Title",
		  *     "url": "https://example.com",
		  *     "description": "This is a description that supports markdown txt",
		  *     "color": 1681177,
		  *     "footer": {
		  *       "text": "This is a footer"
		  *      }
		  *    }]
		  * }
		  */
        private static DiscordEmbedMsg ConstructBodyString(string title, string? url, string description, string? author, int color)
        {
            return new DiscordEmbedMsg()
            {
                Username = "Azure Devops",
                AvatarUrl = "https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcTkhERSc6r4X73FQTWhB2F_0OYlq7qZMfZcIzarA08oZNbB3ZYjEBfCOo3DhvLlOv_02ww&usqp=CAU",
                Embeds = new List<Embed>()
                {
                    new Embed()
                    {
                        Title = title,
                        Url = url,
                        Description = Truncate(description, MAX_DESCRIPTION_LENGTH),
                        Color = color,
                        Footer = new EmbedFooter()
                        {
                            Text = author
                        }
                    }
                }
            };
        }

        private static string? Truncate(string? value, int maxLength)
        {
            if (!string.IsNullOrEmpty(value) && value.Length > maxLength)
            {
                return value.Substring(0, maxLength);
            }
            return value;
        }
    }
}