crestapps-core-response-handlers

CrestApps.Core Response Handlers - Prompt Templates

Implement Response Handlers

Implement IChatResponseHandler when a message should not always use the default AI orchestration path. A handler returns either ChatResponseHandlerResult.Streaming(...) with an IAsyncEnumerable<ChatResponseUpdate> or ChatResponseHandlerResult.Deferred() when a later callback, background task, or relay will deliver the response.

ChatResponseHandlerContext exposes Prompt, ConnectionId, SessionId, ChatType, ConversationHistory, Services, Profile, ChatSession, Interaction, AssistantAppearance, and Properties. Profile and ChatSession are populated only for AIChatSession; Interaction is populated only for ChatInteraction.

Deferred Webhook Example

using System.Net.Http.Json;
using CrestApps.Core.AI.ResponseHandling;

public sealed class WebhookResponseHandler(IHttpClientFactory httpClientFactory) : IChatResponseHandler
{
    public string Name => "webhook";

    public async Task<ChatResponseHandlerResult> HandleAsync(
        ChatResponseHandlerContext context,
        CancellationToken cancellationToken = default)
    {
        var client = httpClientFactory.CreateClient();
        var response = await client.PostAsJsonAsync(
            "https://example.com/chat",
            new
            {
                context.SessionId,
                context.ConnectionId,
                context.ChatType,
                prompt = context.Prompt,
            },
            cancellationToken);

        response.EnsureSuccessStatusCode();

        return ChatResponseHandlerResult.Deferred();
    }
}

Register the handler as scoped:

builder.Services.AddScoped<IChatResponseHandler, WebhookResponseHandler>();

Handler Selection

The resolver selects by AIChatSession.ResponseHandlerName or ChatInteraction.ResponseHandlerName. For a profile-created session, set ResponseHandlerProfileSettings.InitialResponseHandlerName; the active session can change its handler name later. An empty or unknown name falls back to the built-in AI handler. Conversation mode always uses that AI handler, even when a custom name is requested.