Add UseConfiguration method (#68)

README.md

@@ -100,7 +100,7 @@ If necessary, it is possibile to provide a custom Cache by implementing the [ICh
 
 We can also set ChatGPT parameters for chat completion at startup. Check the [official documentation](https://platform.openai.com/docs/api-reference/chat/create) for the list of available parameters and their meaning.
 
-## Configuration using an external source
+### Configuration using an external source
 
 The configuration can be automatically read from [IConfiguration](https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.configuration.iconfiguration), using for example a _ChatGPT_ section in the _appsettings.json_ file:
 
@@ -130,7 +130,7 @@ And then use the corresponding overload of che **AddChatGpt** method:
     // Adds ChatGPT service using settings from IConfiguration.
     builder.Services.AddChatGpt(builder.Configuration);
 
-## Configuring ChatGptNet dinamically
+### Configuring ChatGptNet dinamically
 
 The **AddChatGpt** method has also an overload that accepts an [IServiceProvider](https://learn.microsoft.com/dotnet/api/system.iserviceprovider) as argument. It can be used, for example, if we're in a Web API and we need to support scenarios in which every user has a different API Key that can be retrieved accessing a database via Dependency Injection:
 
@@ -144,6 +144,22 @@ The **AddChatGpt** method has also an overload that accepts an [IServiceProvider
         options.UseOpenAI(apiKyey);
     });
 
+### Configuring ChatGptNet using both IConfiguration and code
+
+In more complex scenarios, it is possible to configure **ChatGptNet** using both code and [IConfiguration](https://learn.microsoft.com/en-us/dotnet/api/microsoft.extensions.configuration.iconfiguration). This can be useful if we want to set a bunch of common properties, but at the same time we need some configuration logic. For example:
+
+    builder.Services.AddChatGpt((services, options) =>
+    {
+        // Configure common properties (message limit and expiration, default parameters, ecc.) using IConfiguration.
+        options.UseConfiguration(builder.Configuration);
+
+        var accountService = services.GetRequiredService<IAccountService>();
+
+        // Dynamically gets the API Key from the service.
+        var apiKey = "..."        
+
+        options.UseOpenAI(apiKyey);
+    });
 
 ## Usage
 

samples/ChatGptApi/Program.cs

@@ -12,7 +12,7 @@
     options.SerializerOptions.DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull;
 });
 
-// Adds ChatGPT service with hard-coded settings.
+// Adds ChatGPT service and configure options via code.
 //builder.Services.AddChatGpt(options =>
 //{
 //    // OpenAI.

samples/ChatGptBlazor.Wasm/Program.cs

@@ -9,6 +9,7 @@
 
 builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });
 
+// Adds ChatGPT service and configure options via code.
 builder.Services.AddChatGpt(options =>
 {
     // OpenAI.

samples/ChatGptConsole/Program.cs

@@ -14,7 +14,12 @@ static void ConfigureServices(HostBuilderContext context, IServiceCollection ser
 {
     services.AddSingleton<Application>();
 
-    // Adds ChatGPT service with hard-coded settings.
+    // Adds ChatGPT service using settings from IConfiguration.
+    services.AddChatGpt(context.Configuration)
+    //.WithCache<LocalMessageCache>() // Uncomment this line to use a custom cache implementation instead of the default MemoryCache.
+    ;
+
+    // Adds ChatGPT service and configure options via code.
     //services.AddChatGpt(options =>
     //{
     //    // OpenAI.
@@ -28,10 +33,14 @@ static void ConfigureServices(HostBuilderContext context, IServiceCollection ser
     //    options.MessageExpiration = TimeSpan.FromMinutes(5);    // Default: 1 hour
     //});
 
-    // Adds ChatGPT service using settings from IConfiguration.
-    services.AddChatGpt(context.Configuration)
-    //.WithCache<LocalMessageCache>() // Uncomment this line to use a custom cache implementation instead of the default MemoryCache.
-    ;
+    // Adds ChatGPT service using settings from IConfiguration and code.
+    //services.AddChatGpt(options =>
+    //{
+    //    options.UseConfiguration(context.Configuration);
+
+    //    options.UseOpenAI(apiKey: "");
+    //    options.DefaultModel = OpenAIChatGptModels.Gpt35Turbo;
+    //});
 }
 
 public class LocalMessageCache : IChatGptCache

samples/ChatGptStreamConsole/Program.cs

@@ -13,7 +13,7 @@ static void ConfigureServices(HostBuilderContext context, IServiceCollection ser
 {
     services.AddSingleton<Application>();
 
-    // Adds ChatGPT service with hard-coded settings.
+    // Adds ChatGPT service and configure options via code.
     //services.AddChatGpt(options =>
     //{
     //    // OpenAI.

src/ChatGptNet/ChatGptOptionsBuilder.cs

@@ -45,7 +45,7 @@ public class ChatGptOptionsBuilder
     ///  Gets or sets the default parameters for chat completion.
     /// </summary>
     /// <see cref="ChatGptParameters"/>
-    public ChatGptParameters DefaultParameters { get; } = new();
+    public ChatGptParameters? DefaultParameters { get; set; } = new();
 
     /// <summary>
     /// Gets or sets the user identification for chat completion, which can help OpenAI to monitor and detect abuse.
@@ -60,7 +60,7 @@ internal ChatGptOptions Build()
         {
             MessageLimit = MessageLimit,
             DefaultModel = DefaultModel,
-            DefaultParameters = DefaultParameters,
+            DefaultParameters = DefaultParameters ?? new(),
             MessageExpiration = MessageExpiration,
             ThrowExceptionOnError = ThrowExceptionOnError,
             ServiceConfiguration = ServiceConfiguration,

src/ChatGptNet/ChatGptOptionsBuilderExtensions.cs

@@ -1,4 +1,5 @@
 using ChatGptNet.ServiceConfigurations;
+using Microsoft.Extensions.Configuration;
 
 namespace ChatGptNet;
 
@@ -62,4 +63,24 @@ public static ChatGptOptionsBuilder UseAzure(this ChatGptOptionsBuilder builder,
 
         return builder;
     }
+
+    /// <summary>
+    /// Configures the <see cref="ChatGptClient"/> reading configuration from the specified <see cref="IConfiguration"/> source.
+    /// </summary>
+    /// <param name="builder">The <see cref="ChatGptOptionsBuilder"/> object to configure.</param>
+    /// <param name="configuration">The <see cref="IConfiguration"/> being bound.</param>
+    /// <param name="sectionName">The name of the configuration section that holds ChatGPT settings (default: ChatGPT).</param>
+    /// <returns>A reference to this instance after the operation has completed.</returns>
+    /// <seealso cref="ChatGptOptionsBuilder"/>
+    /// <seealso cref="IConfiguration"/>
+    public static ChatGptOptionsBuilder UseConfiguration(this ChatGptOptionsBuilder builder, IConfiguration configuration, string sectionName = "ChatGPT")
+    {
+        var configurationSection = configuration.GetSection(sectionName);
+        configurationSection.Bind(builder);
+
+        // Creates the service configuration (OpenAI or Azure) according to the configuration settings.
+        builder.ServiceConfiguration = ChatGptServiceConfiguration.Create(configurationSection);
+
+        return builder;
+    }
 }

src/ChatGptNet/ChatGptServiceCollectionExtensions.cs

@@ -59,11 +59,7 @@ public static IChatGptBuilder AddChatGpt(this IServiceCollection services, IConf
         ArgumentNullException.ThrowIfNull(configuration);
 
         var options = new ChatGptOptionsBuilder();
-        var configurationSection = configuration.GetSection(sectionName);
-        configurationSection.Bind(options);
-
-        // Creates the service configuration (OpenAI or Azure) according to the configuration settings.
-        options.ServiceConfiguration = ChatGptServiceConfiguration.Create(configurationSection);
+        options.UseConfiguration(configuration, sectionName);
 
         SetMissingDefaults(options);
         services.AddSingleton(options.Build());

src/ChatGptNet/Models/ChatGptResponse.cs

@@ -9,7 +9,7 @@ namespace ChatGptNet.Models;
 public class ChatGptResponse
 {
     /// <summary>
-    /// Gets or sets the Id of the response
+    /// Gets or sets the Id of the response.
     /// </summary>
     public string Id { get; set; } = string.Empty;
 

src/ChatGptNet/ServiceConfigurations/OpenAIChatGptServiceConfiguration.cs

@@ -26,7 +26,7 @@ public OpenAIChatGptServiceConfiguration(IConfiguration configuration)
     }
 
     /// <inheritdoc />
-    public override Uri GetServiceEndpoint(string? modelName) => new("https://api.openai.com/v1/chat/completions");
+    public override Uri GetServiceEndpoint(string? _) => new("https://api.openai.com/v1/chat/completions");
 
     /// <inheritdoc />
     public override IDictionary<string, string?> GetRequestHeaders()