add history chat example

LLama.WebAPI/Controllers/ChatController.cs

@@ -1,3 +1,4 @@
+using LLama.Common;
 using LLama.WebAPI.Models;
 using LLama.WebAPI.Services;
 using Microsoft.AspNetCore.Mvc;
@@ -9,20 +10,29 @@ namespace LLama.WebAPI.Controllers
     [Route("[controller]")]
     public class ChatController : ControllerBase
     {
-        private readonly StatefulChatService _service;
         private readonly ILogger<ChatController> _logger;
 
-        public ChatController(ILogger<ChatController> logger,
-            StatefulChatService service)
+        public ChatController(ILogger<ChatController> logger)
         {
             _logger = logger;
-            _service = service;
         }
 
         [HttpPost("Send")]
-        public string SendMessage([FromBody] SendMessageInput input)
+        public string SendMessage([FromBody] SendMessageInput input, [FromServices] StatefulChatService _service)
         {
             return _service.Send(input);
         }
+
+        [HttpPost("History")]
+        public async Task<string> SendHistory([FromBody] HistoryInput input, [FromServices] StatelessChatService _service)
+        {
+            var history = new ChatHistory();
+
+            var messages = input.Messages.Select(m => new ChatHistory.Message(Enum.Parse<AuthorRole>(m.Role), m.Content));
+
+            history.Messages.AddRange(messages);
+
+            return await _service.SendAsync(history);
+        }
     }
 }

LLama.WebAPI/Models/SendMessageInput.cs

@@ -4,3 +4,13 @@ public class SendMessageInput
 {
     public string Text { get; set; }
 }
+
+public class HistoryInput
+{
+    public List<HistoryItem> Messages { get; set; }
+    public class HistoryItem
+    {
+        public string Role { get; set; }
+        public string Content { get; set; }
+    }
+}

LLama.WebAPI/Services/StatefulChatService.cs

@@ -16,8 +16,7 @@ public class StatefulChatService : IDisposable
     public StatefulChatService(IConfiguration configuration)
     {
         _model = new LLamaModel(new Common.ModelParams(configuration["ModelPath"], contextSize: 512));
-        _session = new ChatSession(new InteractiveExecutor(_model))
-            ;//.WithOutputTransform(new LLamaTransforms.KeywordTextOutputStreamTransform(new string[] { "User:", "Assistant:" }, redundancyLength: 8));
+        _session = new ChatSession(new InteractiveExecutor(_model));
     }
 
     public void Dispose()

LLama.WebAPI/Services/StatelessChatService.cs

@@ -1,6 +1,48 @@
-namespace LLama.WebAPI.Services
+using LLama.Common;
+using Microsoft.AspNetCore.Http;
+using System.Text;
+using static LLama.LLamaTransforms;
+
+namespace LLama.WebAPI.Services
 {
     public class StatelessChatService
     {
+        private readonly LLamaModel _model;
+        private readonly ChatSession _session;
+
+        public StatelessChatService(IConfiguration configuration)
+        {
+            _model = new LLamaModel(new ModelParams(configuration["ModelPath"], contextSize: 512));
+            // TODO: replace with a stateless executor
+            _session = new ChatSession(new InteractiveExecutor(_model))
+                        .WithOutputTransform(new LLamaTransforms.KeywordTextOutputStreamTransform(new string[] { "User:", "Assistant:" }, redundancyLength: 8))
+                        .WithHistoryTransform(new HistoryTransform());
+        }
+
+        public async Task<string> SendAsync(ChatHistory history)
+        {
+            var result = _session.ChatAsync(history, new InferenceParams()
+            {
+                AntiPrompts = new string[] { "User:" },
+            });
+
+            var sb = new StringBuilder();
+            await foreach (var r in result)
+            {
+                Console.Write(r);
+                sb.Append(r);
+            }
+
+            return sb.ToString();
+
+        }
+    }
+    public class HistoryTransform : DefaultHistoryTransform
+    {
+        public override string HistoryToText(ChatHistory history)
+        {
+            return base.HistoryToText(history) + "\n Assistant:";
+        }
+
     }
 }