MediaTypeResolver class

Single source of truth for MIME type mapping, extension normalization, media type detection, and MessageType inference from attachments.

Use resolveAttachment whenever building a FileAttachment from raw server data to guarantee consistent extension normalization and MIME derivation.

Use inferMessageType after building attachments to determine the correct MessageType — do not rely on the server's raw type string when attachments are present.

Constructors

MediaTypeResolver({AttachmentTypeStrategy strategy = const DefaultAttachmentTypeStrategy()})

const

Properties

hashCode → int

The hash code for this object.

no setter, inherited

runtimeType → Type

A representation of the runtime type of the object.

no setter, inherited

strategy → AttachmentTypeStrategy

final

Methods

extensionFromFileName(String fileName) → String

Extracts the extension from fileName (no leading dot, lowercase). Returns '' if the name has no extension.

extensionFromMimeType(String mimeType) → String

Returns the canonical extension for mimeType, or '' if unrecognized.

inferMessageType(List<FileAttachment> attachments) → MessageType

Infers MessageType from a list of FileAttachments.

inferMessageTypeFromExtension(String extension) → MessageType

inferMessageTypeFromUrl(String? url, String? mimeType) → MessageType

Infers MessageType from a URL when attachment is uploading.

isAudio(String extension) → bool

isImage(String extension) → bool

isVideo(String extension) → bool

mimeTypeFromExtension(String extension) → String

Returns the canonical MIME type for extension. Falls back to 'application/octet-stream' for unknown extensions.

normalizeExtension(String raw) → String

Strips a leading dot and lowercases raw. '.JPG' → 'jpg', 'PDF' → 'pdf', '' → ''.

noSuchMethod(Invocation invocation) → dynamic

Invoked when a nonexistent method or property is accessed.

inherited

resolveAttachment({required String id, required String url, required String fileName, String? rawExtension, String? rawMimeType, int size = 0, int? pageCount, String? thumbnailUrl, int? width, int? height, String? thumbhash, String? blurhash, Duration? duration, List<double>? waveform}) → FileAttachment

Builds a FileAttachment from raw server data, normalizing rawExtension and deriving mimeType consistently.

resolveExtension(String rawExtension, {String? fallbackFileName}) → String

Resolves the best extension from an explicit raw extension with a filename fallback.

toString() → String

A string representation of this object.

inherited

Operators

operator ==(Object other) → bool

The equality operator.

inherited