修改OpenAI原格式的转发逻辑和参数

2025-11-23 18:17:00 +08:00 · 2025-11-23 18:17:00 +08:00 · 8019b24b61
commit 8019b24b61
parent 5875ffe671
3 changed files with 89 additions and 44 deletions
--- a/LMS.Repository/Forward/ForwardModel.cs
+++ b/LMS.Repository/Forward/ForwardModel.cs
@ -46,3 +46,9 @@ public class ForwardModel
    [Required]
    public string Word { get; set; } = string.Empty;
 }
+
+public class ForwardModelOpenAI : ForwardModel
+{
+    [Required]
+    public string OpenAIBodyString { get; set; } = string.Empty;
+}
--- a/LMS.service/Controllers/ForwardController.cs
+++ b/LMS.service/Controllers/ForwardController.cs
@ -87,11 +87,12 @@ public class ForwardController(ForwardWordService forwardWordService, ILogger<Fo

    [HttpPost]
    [Route("/lms/Forward/forward-stream-struct")]
-    public async Task<IActionResult> ForwardStreamStruct([FromBody] ForwardModel req)
+    public async Task<IActionResult> ForwardStreamStruct([FromBody] ForwardModelOpenAI req)
    {
-        HttpResponseMessage? upstreamResponse;
+        HttpResponseMessage? upstreamResponse = null;
        try
        {
+            // 1. Service 层请求 (保持不变，这里已经是 HeadersRead 模式了)
            upstreamResponse = await _forwardWordService.ForwardWordStreamRaw(req);
        }
        catch (Exception e)
@ -99,54 +100,60 @@ public class ForwardController(ForwardWordService forwardWordService, ILogger<Fo
            return BadRequest(e.Message);
        }

-        // 处理上游响应与转发
        try
        {
-            // A. 上游 OpenAI 报错 (如 401 key 错误, 429 限流, 500 等)
-            // 我们需要透传这个错误给前端，而不是报 400
+            // 2. 处理错误情况
            if (!upstreamResponse.IsSuccessStatusCode)
            {
                Response.StatusCode = (int)upstreamResponse.StatusCode;
-
+                // 复制 Content-Type，防止前端解析乱码
                if (upstreamResponse.Content.Headers.ContentType != null)
-                {
                    Response.ContentType = upstreamResponse.Content.Headers.ContentType.ToString();
-                }

-                // 直接读取错误内容并写入
                var errorContent = await upstreamResponse.Content.ReadAsStringAsync();
                await Response.WriteAsync(errorContent);
-
-                // 显式返回空结果，告诉框架处理结束
                return new EmptyResult();
            }

-            // B. 上游成功 (200 OK) -> 建立 SSE 管道
-            HttpContext.Response.ContentType = "text/event-stream";
-            HttpContext.Response.Headers.Add("Cache-Control", "no-cache");
-            HttpContext.Response.Headers.Add("Connection", "keep-alive");
+            // 3. 成功连接，设置 SSE 响应头
+            Response.ContentType = "text/event-stream";
+            Response.Headers.Add("Cache-Control", "no-cache");
+            Response.Headers.Add("Connection", "keep-alive");
+            // 禁用缓冲 (对于某些服务器环境很重要)
+            // var responseFeature = HttpContext.Features.Get<IHttpResponseBodyFeature>();
+            // responseFeature?.DisableBuffering(); 

-            // 获取上游流
-            await using var stream = await upstreamResponse.Content.ReadAsStreamAsync();
+            // 4. 【核心修改】手动流式转发循环
+            await using var upstreamStream = await upstreamResponse.Content.ReadAsStreamAsync();

-            // 开始流式复制
-            // CopyToAsync 会自动处理缓冲，直到上游流结束
-            await stream.CopyToAsync(Response.Body);
-            await Response.Body.FlushAsync();
+            // 定义一个较小的缓冲区，比如 1024 甚至更小，其实 buffer 大小不影响实时性，因为 ReadAsync 会在收到任何数据时立即返回
+            var buffer = new byte[4096];
+            int bytesRead;
+
+            // 使用 HttpContext.RequestAborted，这样前端断开时后端也会停止读取
+            while ((bytesRead = await upstreamStream.ReadAsync(buffer, HttpContext.RequestAborted)) != 0)
+            {
+                // 收到多少发多少
+                await Response.Body.WriteAsync(buffer.AsMemory(0, bytesRead), HttpContext.RequestAborted);
+
+                // 【关键】立刻刷新缓冲区，将数据强制推送到网络
+                await Response.Body.FlushAsync(HttpContext.RequestAborted);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            // 客户端(前端)主动断开连接，这是正常现象，不做处理
        }
        catch (Exception)
        {
-            if (!Response.HasStarted)
-            {
-                return StatusCode(502, "Upstream connection failed.");
-            }
+            // 网络异常处理
+            if (!Response.HasStarted) return StatusCode(502);
        }
        finally
        {
            upstreamResponse?.Dispose();
        }

-        // 兜底返回，确保所有路径都有返回值
        return new EmptyResult();
    }

--- a/LMS.service/Service/ForwardWordService.cs
+++ b/LMS.service/Service/ForwardWordService.cs
@ -9,6 +9,7 @@ using LMS.Repository.Model;
 using Microsoft.AspNetCore.Mvc;
 using Microsoft.EntityFrameworkCore;
 using Newtonsoft.Json;
+using Newtonsoft.Json.Linq;
 using System.Net;
 using System.Net.Http.Headers;
 using System.Text;
@ -238,15 +239,16 @@ public class ForwardWordService(ApplicationDbContext context, IHttpClientFactory
    #endregion
    #region OpenAI 格式流式返回接口（保留接口），需要系统数据

-    public async Task<HttpResponseMessage> ForwardWordStreamRaw(ForwardModel request)
+    public async Task<HttpResponseMessage> ForwardWordStreamRaw(ForwardModelOpenAI request)
    {
        // --- 1. 基础校验 (保持原有逻辑) ---
-        if (string.IsNullOrEmpty(request.Word)) throw new Exception("参数错误");
+        if (string.IsNullOrWhiteSpace(request.OpenAIBodyString))
+        {
+            throw new Exception("OpenAIBodyString 不能为空");
+        }
        if (string.IsNullOrEmpty(request.GptUrl)) throw new Exception("请求的url为空");

        var allowedUrls = new[] {
-        "https://ark.cn-beijing.volces.com",
-        "https://api.moonshot.cn",
        "https://laitool.net",
        "https://api.laitool.cc",
        "https://laitool.cc",
@ -266,6 +268,24 @@ public class ForwardWordService(ApplicationDbContext context, IHttpClientFactory
            throw new Exception("机器码不存在或已过期");
        }

+        // ================= 2. JSON 结构解析与校验 =================
+        JObject jsonBody;
+        try
+        {
+            jsonBody = JObject.Parse(request.OpenAIBodyString);
+        }
+        catch (JsonReaderException)
+        {
+            throw new Exception("OpenAIBodyString 不是有效的 JSON 格式");
+        }
+
+        // 检查 messages 是否存在且为数组
+        var messages = jsonBody["messages"] as JArray;
+        if (messages == null || messages.Count == 0)
+        {
+            throw new Exception("请求体结构错误: 缺少 'messages' 数组");
+        }
+
        // --- 2. 获取提示词预设 (保持原有逻辑) ---
        Prompt? prompt = await _context.Prompt.FirstOrDefaultAsync(x => x.PromptTypeId == request.PromptTypeId && x.Id == request.PromptId);
        if (prompt == null)
@ -273,23 +293,35 @@ public class ForwardWordService(ApplicationDbContext context, IHttpClientFactory
            throw new Exception("FindPromptStringFail"); // 建议使用具体错误码
        }

-        // --- 3. 手动构建 OpenAI 格式的请求体 ---
-        // SDK 帮你做了这一步，现在我们要自己做，以便获得原始流
-        var payload = new
+        // ================= 4. 替换逻辑 (System) =================
+        // 遍历寻找 role 为 system 的消息
+        var systemMsg = messages.FirstOrDefault(m => m["role"]?.ToString() == "system");
+        if (systemMsg != null)
        {
-            model = request.Model,
-            messages = new List<object>
+            // 没有数据 默认为 "{{SYSTEM}}"
+            var content = systemMsg["content"]?.ToString() ?? "{{SYSTEM}}";
+            // 检查是否包含占位符 "{{SYSTEM}}"
+            if (content.Contains("{{SYSTEM}}"))
+            {
+                // 替换占位符为真实的 promptString
+                systemMsg["content"] = content.Replace("{{SYSTEM}}", prompt.PromptString);
+            }
+        }
+        else
        {
-            new { role = "system", content = prompt.PromptString },
-            new { role = "user", content = request.Word }
-        },
-            stream = true, // 必须开启流式
-                           // max_tokens = 2000, // 如果有需要可以加其他参数
-                           // temperature = 0.7
-        };
+            throw new Exception("缺少 system 消息节点");
+        }

-        var jsonContent = JsonConvert.SerializeObject(payload, new JsonSerializerSettings { ContractResolver = new LowercaseContractResolver() });
-        var httpContent = new StringContent(jsonContent, Encoding.UTF8, "application/json");
+        // ================= 5. 强制修正关键字段 =================
+        // 强制使用 C# 模型类中指定的 Model，或者校验两者是否一致 (这里选择覆盖，以 C# 参数为准)
+        jsonBody["model"] = request.Model;
+
+        // 强制开启流式
+        jsonBody["stream"] = true;
+        var finalJsonContent = jsonBody.ToString(Formatting.None);
+
+        //var jsonContent = JsonConvert.SerializeObject(finalJsonContent, new JsonSerializerSettings { ContractResolver = new LowercaseContractResolver() });
+        var httpContent = new StringContent(finalJsonContent, Encoding.UTF8, "application/json");

        // --- 4. 发起 HTTP 请求 ---
        var client = _httpClientFactory.CreateClient(); // 或者直接 new HttpClient();