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| 1 | +// Copyright (c) Microsoft Corporation. All rights reserved. |
| 2 | +// KernelPluginMiddleware.cs |
| 3 | + |
| 4 | +using System; |
| 5 | +using System.Linq; |
| 6 | +using System.Text.Json; |
| 7 | +using System.Text.Json.Nodes; |
| 8 | +using System.Threading; |
| 9 | +using System.Threading.Tasks; |
| 10 | +using AutoGen.SemanticKernel.Extension; |
| 11 | +using Microsoft.SemanticKernel; |
| 12 | + |
| 13 | +namespace AutoGen.SemanticKernel; |
| 14 | + |
| 15 | +/// <summary> |
| 16 | +/// A middleware that consumes <see cref="KernelPlugin"/> |
| 17 | +/// </summary> |
| 18 | +public class KernelPluginMiddleware : IMiddleware |
| 19 | +{ |
| 20 | + private readonly KernelPlugin _kernelPlugin; |
| 21 | + private readonly FunctionCallMiddleware _functionCallMiddleware; |
| 22 | + public string? Name => nameof(KernelPluginMiddleware); |
| 23 | + |
| 24 | + public KernelPluginMiddleware(Kernel kernel, KernelPlugin kernelPlugin) |
| 25 | + { |
| 26 | + _kernelPlugin = kernelPlugin; |
| 27 | + var functionContracts = kernelPlugin.Select(k => k.Metadata.ToFunctionContract()); |
| 28 | + var functionMap = kernelPlugin.ToDictionary(kv => kv.Metadata.Name, kv => InvokeFunctionPartial(kernel, kv)); |
| 29 | + _functionCallMiddleware = new FunctionCallMiddleware(functionContracts, functionMap, Name); |
| 30 | + } |
| 31 | + |
| 32 | + public Task<IMessage> InvokeAsync(MiddlewareContext context, IAgent agent, CancellationToken cancellationToken = default) |
| 33 | + { |
| 34 | + return _functionCallMiddleware.InvokeAsync(context, agent, cancellationToken); |
| 35 | + } |
| 36 | + |
| 37 | + private async Task<string> InvokeFunctionAsync(Kernel kernel, KernelFunction function, string arguments) |
| 38 | + { |
| 39 | + var kernelArguments = new KernelArguments(); |
| 40 | + var parameters = function.Metadata.Parameters; |
| 41 | + var jsonObject = JsonSerializer.Deserialize<JsonObject>(arguments) ?? new JsonObject(); |
| 42 | + foreach (var parameter in parameters) |
| 43 | + { |
| 44 | + var parameterName = parameter.Name; |
| 45 | + if (jsonObject.ContainsKey(parameterName)) |
| 46 | + { |
| 47 | + var parameterType = parameter.ParameterType ?? throw new ArgumentException($"Missing parameter type for {parameterName}"); |
| 48 | + var parameterValue = jsonObject[parameterName]; |
| 49 | + var parameterObject = parameterValue.Deserialize(parameterType); |
| 50 | + kernelArguments.Add(parameterName, parameterObject); |
| 51 | + } |
| 52 | + else |
| 53 | + { |
| 54 | + if (parameter.DefaultValue != null) |
| 55 | + { |
| 56 | + kernelArguments.Add(parameterName, parameter.DefaultValue); |
| 57 | + } |
| 58 | + else if (parameter.IsRequired) |
| 59 | + { |
| 60 | + throw new ArgumentException($"Missing required parameter: {parameterName}"); |
| 61 | + } |
| 62 | + } |
| 63 | + } |
| 64 | + var result = await function.InvokeAsync(kernel, kernelArguments); |
| 65 | + |
| 66 | + return result.ToString(); |
| 67 | + } |
| 68 | + |
| 69 | + private Func<string, Task<string>> InvokeFunctionPartial(Kernel kernel, KernelFunction function) |
| 70 | + { |
| 71 | + return async (string args) => |
| 72 | + { |
| 73 | + var result = await InvokeFunctionAsync(kernel, function, args); |
| 74 | + return result.ToString(); |
| 75 | + }; |
| 76 | + } |
| 77 | +} |
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