Yi.Framework/Yi.Abp.Net8/module/ai-hub/Yi.Framework.AiHub.Application/Services/AiService.cs

using System.Text;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Options;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
using OpenAI.Chat;
using Volo.Abp.Application.Services;
using Yi.Framework.AiHub.Application.Contracts.Dtos;
using Yi.Framework.AiHub.Application.Contracts.Options;
using Yi.Framework.AiHub.Domain.Managers;

namespace Yi.Framework.AiHub.Application.Services;

public class AiService : ApplicationService
{
    private readonly AiGateWayOptions _options;
    private readonly IHttpContextAccessor _httpContextAccessor;

    public AiService(IOptions<AiGateWayOptions> options, IHttpContextAccessor httpContextAccessor)
    {
        _options = options.Value;
        this._httpContextAccessor = httpContextAccessor;
    }


    /// <summary>
    /// 获取模型列表
    /// </summary>
    /// <returns></returns>
    public async Task<List<ModelGetListOutput>> GetModelAsync()
    {
        var output = _options.Chats.SelectMany(x => x.Value.ModelIds)
            .Select(x => new ModelGetListOutput()
            {
                Id = 001,
                Category = "chat",
                ModelName = x,
                ModelDescribe = "这是一个直连模型",
                ModelPrice = 4,
                ModelType = "1",
                ModelShow = "0",
                Remark = "直连模型"
            }).ToList();
        return output;
    }


    /// <summary>
    /// 发送消息
    /// </summary>
    /// <param name="input"></param>
    /// <param name="cancellationToken"></param>
    public async Task PostSendAsync(SendMessageInput input, CancellationToken cancellationToken)
    {
        var httpContext = this._httpContextAccessor.HttpContext;
        var response = httpContext.Response;
        // 设置响应头，声明是 SSE 流
        response.ContentType = "text/event-stream";
        response.Headers.Append("Cache-Control", "no-cache");
        response.Headers.Append("Connection", "keep-alive");


        var history = new List<ChatMessage>();
        foreach (var aiChatContextDto in input.Messages)
        {
            if (aiChatContextDto.Role == "ai")
            {
                history.Add(ChatMessage.CreateAssistantMessage(aiChatContextDto.Content));
            }
            else if (aiChatContextDto.Role == "user")
            {
                history.Add(ChatMessage.CreateUserMessage(aiChatContextDto.Content));
            }
        }

        var gateWay = LazyServiceProvider.GetRequiredService<AiGateWayManager>();
        var completeChatResponse = gateWay.CompleteChatAsync(input.Model, history,cancellationToken);
        await using var writer = new StreamWriter(response.Body, Encoding.UTF8, leaveOpen: true);
        await foreach (var data in completeChatResponse)
        {
            var model = MapToMessage(input.Model, data);
            var message = JsonConvert.SerializeObject(model, new JsonSerializerSettings
            {
                ContractResolver = new CamelCasePropertyNamesContractResolver()
            });

            await writer.WriteLineAsync($"data: {message}\n");
            await writer.FlushAsync(cancellationToken); // 确保立即推送数据
        }
        
        //断开连接
        await writer.WriteLineAsync($"data: done\n");
        await writer.FlushAsync(cancellationToken); // 确保立即推送数据
    }


    private SendMessageOutputDto MapToMessage(string modelId, string content)
    {
        var output = new SendMessageOutputDto
        {
            Id = 001,
            Object = "chat.completion.chunk",
            Created = 1750336171,
            Model = modelId,
            Choices = new()
            {
                new Choice
                {
                    Index = 0,
                    Delta = new Delta
                    {
                        Content = content,
                        Role = "assistant"
                    },
                    FinishReason = null,
                    ContentFilterResults = new()
                    {
                        Hate = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        SelfHarm = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Sexual = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Violence = new()
                        {
                            Filtered = false,
                            Detected = null
                        },
                        Jailbreak = new()
                        {
                            Filtered = false,
                            Detected = false
                        },
                        Profanity = new()
                        {
                            Filtered = false,
                            Detected = false
                        },
                    }
                }
            },
            SystemFingerprint = "",
            Usage = new Usage
            {
                PromptTokens = 75,
                CompletionTokens = 25,
                TotalTokens = 100,
                PromptTokensDetails = new()
                {
                    AudioTokens = 0,
                    CachedTokens = 0
                },
                CompletionTokensDetails = new()
                {
                    AudioTokens = 0,
                    ReasoningTokens = 0,
                    AcceptedPredictionTokens = 0,
                    RejectedPredictionTokens = 0
                }
            }
        };

        return output;
    }
}