foxcord/Foxcord/Rest/DiscordRestClient.cs

using System.Net;
using System.Net.Http.Json;
using System.Text.Json;
using Foxcord.Models;
using Foxcord.Rest.Rate;
using Foxcord.Rest.Types;
using Foxcord.Serialization;
using Polly;
using Serilog;

namespace Foxcord.Rest;

public class DiscordRestClient : BaseRestClient
{
    public DiscordRestClient(ILogger logger, DiscordRestClientOptions options) : base(logger, new RestClientOptions
    {
        JsonSerializerOptions = JsonSerializerOptions,
        ApiBaseUrl = options.ApiBaseUrl ?? DefaultApiBaseUrl,
        UserAgent = options.UserAgent ?? DefaultUserAgent,
        TokenFactory = () => $"Bot {options.Token}",
        ErrorHandler = HandleError,
    })
    {
        Pipeline = new ResiliencePipelineBuilder<HttpResponseMessage>()
            .AddDiscordStrategy(new RateLimiter(logger.ForContext<DiscordRestClient>()))
            .Build();
    }

    public const string DefaultUserAgent = "DiscordBot (https://code.vulpine.solutions/sam/Foxcord, v1)";
    public const string DefaultApiBaseUrl = "https://discord.com/api/v10";

    public async Task<GetGatewayBotResponse> GatewayBotAsync(CancellationToken ct = default) =>
        await RequestAsync<GetGatewayBotResponse>(HttpMethod.Get, "/gateway/bot", ct);

    public async Task<Message> CreateMessageAsync(Snowflake channelId, CreateMessageParams message,
        CancellationToken ct = default) =>
        await RequestAsync<CreateMessageParams, Message>(HttpMethod.Post, $"/channels/{channelId}/messages", message,
            ct);

    #region BaseRestClient parameters

    private static readonly JsonSerializerOptions JsonSerializerOptions = JsonSerializerExtensions.CreateSerializer();

    private static async Task HandleError(HttpResponseMessage resp, CancellationToken ct)
    {
        if (resp.IsSuccessStatusCode) return;

        if (resp.StatusCode == HttpStatusCode.TooManyRequests)
        {
            throw new RateLimitError(resp.Headers);
        }

        var error = await resp.Content.ReadFromJsonAsync<DiscordRestError>(JsonSerializerOptions, ct);
        if (error == null) throw new ArgumentNullException(nameof(resp), "Response was deserialized as null");
        throw error;
    }

    #endregion
}

public class DiscordRestClientOptions
{
    public required string Token { get; init; }
    public string? UserAgent { get; init; }
    public string? ApiBaseUrl { get; init; }
}