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feat: added file-based history (#121)
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| <Project Sdk="Microsoft.NET.Sdk"> | ||
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| <PropertyGroup> | ||
| <OutputType>Exe</OutputType> | ||
| <TargetFramework>net8.0</TargetFramework> | ||
| <ImplicitUsings>enable</ImplicitUsings> | ||
| <Nullable>enable</Nullable> | ||
| </PropertyGroup> | ||
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| <ItemGroup> | ||
| <ProjectReference Include="..\..\src\libs\LangChain\LangChain.csproj" /> | ||
| </ItemGroup> | ||
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| </Project> |
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| @@ -0,0 +1,54 @@ | ||
| using LangChain.Memory; | ||
| using LangChain.Providers.OpenAI; | ||
| using static LangChain.Chains.Chain; | ||
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| var apiKey = Environment.GetEnvironmentVariable("OPENAI_API_KEY") ?? | ||
| throw new InvalidOperationException("OPENAI_API_KEY environment variable is not found."); | ||
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| var model = new OpenAiModel(apiKey, "gpt-3.5-turbo"); | ||
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| // create simple template for conversation for AI to know what piece of text it is looking at | ||
| var template = @" | ||
| The following is a friendly conversation between a human and an AI. | ||
| {history} | ||
| Human: {input} | ||
| AI:"; | ||
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| // To have a conversation thar remembers previous messages we need to use memory. | ||
| // For memory to work properly we need to specify AI and Human prefixes. | ||
| // Since in our template we have "AI:" and "Human:" we need to specify them here. Pay attention to spaces after prefixes. | ||
| var conversationBufferMemory = new ConversationBufferMemory(new FileChatMessageHistory("messages.json")) | ||
| { | ||
| AiPrefix = "AI: ", | ||
| HumanPrefix = "Human: " | ||
| }; | ||
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| // build chain. Notice that we don't set input key here. It will be set in the loop | ||
| var chain = | ||
| // load history. at first it will be empty, but UpdateMemory will update it every iteration | ||
| LoadMemory(conversationBufferMemory, outputKey: "history") | ||
| | Template(template) | ||
| | LLM(model) | ||
| // update memory with new request from Human and response from AI | ||
| | UpdateMemory(conversationBufferMemory, requestKey: "input", responseKey: "text"); | ||
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| // run an endless loop of conversation | ||
| while (true) | ||
| { | ||
| Console.Write("Human: "); | ||
| var input = Console.ReadLine(); | ||
| if (input == "exit") | ||
| break; | ||
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| // build a new chain using previous chain but with new input every time | ||
| var chatChain = Set(input, "input") | ||
| | chain; | ||
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| // get response from AI | ||
| var res = await chatChain.Run("text"); | ||
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| Console.Write("AI: "); | ||
| Console.WriteLine(res); | ||
| } |
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| using LangChain.Providers; | ||
| using System.Text.Json; | ||
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| namespace LangChain.Memory; | ||
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| /// <summary> | ||
| /// Stores history in a local file. | ||
| /// </summary> | ||
| public class FileChatMessageHistory : BaseChatMessageHistory | ||
| { | ||
| private string MessagesFilePath { get; } | ||
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| private List<Message> _messages; | ||
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| /// <inheritdoc/> | ||
| public override IReadOnlyList<Message> Messages | ||
| { | ||
| get | ||
| { | ||
| if (_messages is null) | ||
| { | ||
| LoadMessages().Wait(); | ||
| } | ||
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| return _messages; | ||
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Check warning on line 25 in src/libs/LangChain.Core/Memory/FileChatMessageHistory.cs
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| } | ||
| } | ||
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| /// <summary> | ||
| /// | ||
| /// </summary> | ||
| /// <param name="messagesFilePath">Path to local history file</param> | ||
| /// <exception cref="ArgumentNullException"></exception> | ||
| public FileChatMessageHistory(string messagesFilePath) | ||
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| { | ||
| MessagesFilePath = messagesFilePath ?? throw new ArgumentNullException(nameof(messagesFilePath)); | ||
| } | ||
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| /// <inheritdoc/> | ||
| public override async Task AddMessage(Message message) | ||
| { | ||
| _messages.Add(message); | ||
| await SaveMessages(); | ||
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Check warning on line 43 in src/libs/LangChain.Core/Memory/FileChatMessageHistory.cs
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| } | ||
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| /// <inheritdoc/> | ||
| public override async Task Clear() | ||
| { | ||
| _messages.Clear(); | ||
| await SaveMessages(); | ||
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| } | ||
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| private async Task SaveMessages() | ||
| { | ||
| string json = JsonSerializer.Serialize(_messages); | ||
| await Task.Run(() => File.WriteAllText(MessagesFilePath, json)); | ||
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| } | ||
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| private async Task LoadMessages() | ||
| { | ||
| if (File.Exists(MessagesFilePath)) | ||
| { | ||
| string json = await Task.Run(() => File.ReadAllText(MessagesFilePath)); | ||
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| _messages = JsonSerializer.Deserialize<List<Message>>(json); | ||
| } | ||
| else | ||
| { | ||
| _messages = new List<Message>(); | ||
| } | ||
| } | ||
| } | ||
