feat: initial implementation of creating a file via the Files API

src/AnthropicClient/Models/AnthropicFile.cs

@@ -0,0 +1,53 @@
+using System.Text.Json.Serialization;
+
+namespace AnthropicClient.Models;
+
+/// <summary>
+/// Represents a file object from the Anthropic Files API.
+/// </summary>
+public class AnthropicFile
+{
+  /// <summary>
+  /// Unique object identifier.
+  /// The format and length of IDs may change over time.
+  /// </summary>
+  [JsonPropertyName("id")]
+  public string Id { get; init; } = string.Empty;
+
+  /// <summary>
+  /// Object type.
+  /// For files, this is always "file".
+  /// </summary>
+  [JsonPropertyName("type")]
+  public string Type { get; init; } = "file";
+
+  /// <summary>
+  /// Original filename of the uploaded file.
+  /// </summary>
+  [JsonPropertyName("file_name")]
+  public string FileName { get; init; } = string.Empty;
+
+  /// <summary>
+  /// RFC 3339 datetime string representing when the file was created.
+  /// </summary>
+  [JsonPropertyName("created_at")]
+  public string CreatedAt { get; init; } = string.Empty;
+
+  /// <summary>
+  /// Size of the file in bytes.
+  /// </summary>
+  [JsonPropertyName("size_bytes")]
+  public long SizeBytes { get; init; }
+
+  /// <summary>
+  /// MIME type of the file.
+  /// </summary>
+  [JsonPropertyName("file_type")]
+  public string FileType { get; init; } = string.Empty;
+
+  /// <summary>
+  /// Whether the file can be downloaded.
+  /// </summary>
+  [JsonPropertyName("downloadable")]
+  public bool Downloadable { get; init; }
+}

src/AnthropicClient/Models/CreateFileRequest.cs

@@ -0,0 +1,66 @@
+using System.Text.Json.Serialization;
+
+using AnthropicClient.Utils;
+
+namespace AnthropicClient.Models;
+
+/// <summary>
+/// Represents a request to create a file via the Anthropic Files API.
+/// </summary>
+public class CreateFileRequest
+{
+  /// <summary>
+  /// The file content as a byte array.
+  /// </summary>
+  public byte[] File { get; }
+
+  /// <summary>
+  /// The original filename of the file being uploaded.
+  /// </summary>
+  public string FileName { get; }
+
+  /// <summary>
+  /// The MIME type of the file.
+  /// </summary>
+  public string FileType { get; }
+
+  /// <summary>
+  /// Initializes a new instance of the <see cref="CreateFileRequest"/> class.
+  /// </summary>
+  /// <param name="file">The file content as a byte array.</param>
+  /// <param name="fileName">The original filename of the file being uploaded.</param>
+  /// <param name="fileType">The MIME type of the file.</param>
+  /// <exception cref="ArgumentNullException">Thrown when <paramref name="file"/>, <paramref name="fileName"/>, or <paramref name="fileType"/> is null.</exception>
+  public CreateFileRequest(byte[] file, string fileName, string fileType)
+  {
+    ArgumentValidator.ThrowIfNull(file, nameof(file));
+    ArgumentValidator.ThrowIfNullOrWhitespace(fileName, nameof(fileName));
+    ArgumentValidator.ThrowIfNullOrWhitespace(fileType, nameof(fileType));
+
+    File = file;
+    FileName = fileName;
+    FileType = fileType;
+  }
+
+  /// <summary>
+  /// Initializes a new instance of the <see cref="CreateFileRequest"/> class from a stream.
+  /// </summary>
+  /// <param name="stream">The stream containing the file content.</param>
+  /// <param name="fileName">The original filename of the file being uploaded.</param>
+  /// <param name="fileType">The MIME type of the file.</param>
+  /// <exception cref="ArgumentNullException">Thrown when <paramref name="stream"/>, <paramref name="fileName"/>, or <paramref name="fileType"/> is null.</exception>
+  public CreateFileRequest(Stream stream, string fileName, string fileType)
+  {
+    ArgumentValidator.ThrowIfNull(stream, nameof(stream));
+    ArgumentValidator.ThrowIfNullOrWhitespace(fileName, nameof(fileName));
+    ArgumentValidator.ThrowIfNullOrWhitespace(fileType, nameof(fileType));
+
+    using var memoryStream = new MemoryStream();
+    stream.CopyToAsync(memoryStream);
+    var fileContent = memoryStream.ToArray();
+
+    File = fileContent;
+    FileName = fileName;
+    FileType = fileType;
+  }
+}