Relay/RelayClient/ServerAPI.cs

using System.Net.Http.Headers;
using System.Net.Http.Json;
using System.Text.Json;
using RelayShared.Rtc;

namespace RelayClient;

public class ServerAPI
{
    private static readonly HttpClient client = new()
    {
        BaseAddress = new Uri("http://localhost:5000/")
    };

    public static void setupClient()
    {
        client.DefaultRequestHeaders.Accept.Clear();
        client.DefaultRequestHeaders.Accept.Add(
            new MediaTypeWithQualityHeaderValue("application/json"));
    }

    public static async Task PostOfferAsync(RtcOffer offer)
    {
        var response = await client.PostAsJsonAsync("api/rtc/offer", offer);
        response.EnsureSuccessStatusCode();
    }

    public static async Task<List<string>> GetParticipantsForChannelAsync(string channelId)
    {
        var response = await client.GetAsync($"api/rtc/participants/{channelId}");
        response.EnsureSuccessStatusCode();

        var json = await response.Content.ReadAsStringAsync();
        return JsonSerializer.Deserialize<List<string>>(json) ?? [];
    }

    public static async Task<RtcSessionDescription?> GetOfferForChannelAsync(string channelId, string fromUsername, string targetUsername)
    {
        var response = await client.GetAsync($"api/rtc/offer/{channelId}/{fromUsername}/{targetUsername}");
        if (!response.IsSuccessStatusCode)
            return null;

        var json = await response.Content.ReadAsStringAsync();
        return JsonSerializer.Deserialize<RtcSessionDescription>(json);
    }

    public static async Task PostAnswerAsync(RtcAnswer answer)
    {
        var response = await client.PostAsJsonAsync("api/rtc/answer", answer);
        response.EnsureSuccessStatusCode();
    }

    public static async Task<RtcSessionDescription?> GetAnswerForChannelAsync(string channelId, string fromUsername, string targetUsername)
    {
        var response = await client.GetAsync($"api/rtc/answer/{channelId}/{fromUsername}/{targetUsername}");
        if (!response.IsSuccessStatusCode)
            return null;

        var json = await response.Content.ReadAsStringAsync();
        return JsonSerializer.Deserialize<RtcSessionDescription>(json);
    }

    public static async Task PostIceCandidateAsync(DBIceCandidate candidate)
    {
        var response = await client.PostAsJsonAsync("api/rtc/candidate", candidate);
        response.EnsureSuccessStatusCode();
    }

    public static async Task PostLeaveAsync(RtcLeaveRequest leave)
    {
        var response = await client.PostAsJsonAsync("api/rtc/leave", leave);
        response.EnsureSuccessStatusCode();
    }
}