Class AttachmentFactory

Namespace: Wolfgang.Extensions.Mail

Assembly: Wolfgang.Extensions.Mail.dll

Provides factory methods for creating Attachment objects from common sources with automatic content type inference from file extensions.

public static class AttachmentFactory

Inheritance: object

AttachmentFactory

Inherited Members: object.Equals(object)

object.Equals(object, object)

object.GetHashCode()

object.GetType()

object.MemberwiseClone()

object.ReferenceEquals(object, object)

object.ToString()

Methods

FromBase64(string, string, string?)

Creates an Attachment from a base64-encoded string with automatic content type inference.

public static Attachment FromBase64(string base64Content, string fileName, string? contentType = null)

Parameters

base64Content string: The attachment content as a base64-encoded string.
fileName string: The file name for the attachment (used for content type inference and display).
contentType string: Optional explicit content type. When null, inferred from fileName.

Returns

Attachment: A new Attachment backed by a MemoryStream.

Exceptions

ArgumentNullException: base64Content is null.
ArgumentNullException: fileName is null.
FormatException: base64Content is not valid base64.

FromBytes(byte[], string, string?)

Creates an Attachment from a byte array with automatic content type inference.

public static Attachment FromBytes(byte[] content, string fileName, string? contentType = null)

Parameters

content byte[]: The attachment content as a byte array.
fileName string: The file name for the attachment (used for content type inference and display).
contentType string: Optional explicit content type. When null, inferred from fileName.

Returns

Attachment: A new Attachment backed by a MemoryStream.

Examples

byte[] pdfBytes = await File.ReadAllBytesAsync("report.pdf");
var attachment = AttachmentFactory.FromBytes(pdfBytes, "report.pdf");

Exceptions

ArgumentNullException: content is null.
ArgumentNullException: fileName is null.

FromStream(Stream, string, string?)

Creates an Attachment from a Stream with automatic content type inference. The stream content is copied to a new MemoryStream; the original stream is not modified.

public static Attachment FromStream(Stream content, string fileName, string? contentType = null)

Parameters

content Stream: The stream containing the attachment content.
fileName string: The file name for the attachment (used for content type inference and display).
contentType string: Optional explicit content type. When null, inferred from fileName.

Returns

Attachment: A new Attachment backed by a MemoryStream.

Exceptions

ArgumentNullException: content is null.
ArgumentNullException: fileName is null.

InferContentType(string)

Infers the MIME content type from a file name extension. Returns application/octet-stream for unknown extensions.

public static string InferContentType(string fileName)

Parameters

fileName string: The file name to infer the content type from.

Returns

string: The inferred MIME content type string.

Exceptions

ArgumentNullException: fileName is null.

RegisterContentType(string, string)

Registers or overrides a custom content type mapping for a file extension. Extension matching is case-insensitive. Registrations persist for the lifetime of the process.

public static void RegisterContentType(string extension, string contentType)

Parameters

extension string: The file extension (with leading dot, e.g. ".heic").
contentType string: The MIME content type to associate with the extension.

Examples

AttachmentFactory.RegisterContentType(".heic", "image/heic");
byte[] data = await File.ReadAllBytesAsync("photo.heic");
var attachment = AttachmentFactory.FromBytes(data, "photo.heic");
// attachment.ContentType.MediaType == "image/heic"

Remarks

The registry is a process-wide static map shared by every caller in the process. Registration is thread-safe, and concurrent registrations of the same extension resolve to last-write-wins — there is no notification when a mapping is overwritten.

Exceptions

ArgumentNullException: extension is null.
ArgumentNullException: contentType is null.
ArgumentException: extension is empty or does not start with ".".

TryGetRegisteredContentType(string, out string?)

Attempts to retrieve the registered content type for a file extension.

public static bool TryGetRegisteredContentType(string extension, out string? contentType)

Parameters

extension string: The file extension (with leading dot).
contentType string: When this method returns, contains the registered content type if found; otherwise, null.

Returns

bool: true if a content type was registered for the extension; otherwise, false.

Exceptions

ArgumentNullException: extension is null.