# DocumentReader A type that reads a document’s content from a file. ``` protocol DocumentReader ``` ## Overview SwiftUI calls your document’s [`reader(configuration:)`](/documentation/SwiftUI/ReadableDocument/reader(configuration:)) method to obtain a `DocumentReader`, then invokes [`read(from:progress:)`](/documentation/SwiftUI/DocumentReader/read(from:progress:)) in the background with coordinated file access. The returned snapshot is delivered to [`apply(snapshot:previous:)`](/documentation/SwiftUI/ReadableDocument/apply(snapshot:previous:)) on the main actor. Use [`FileWrapperDocumentReader`](/documentation/SwiftUI/FileWrapperDocumentReader) for cases that don’t require custom file read logic. Implement a `DocumentReader` when you need direct URL access for frameworks like Core Graphics, AVFoundation, or PDFKit: ``` struct ImageReader: DocumentReader { @concurrent func read(from source: URL, progress: consuming Subprogress) async throws -> sending CGImage { guard let provider = CGDataProvider(url: source as CFURL), let image = CGImage( jpegDataProviderSource: provider, decode: nil, shouldInterpolate: true, intent: .defaultIntent ) else { throw CocoaError(.fileReadCorruptFile) } return image } } ``` SwiftUI provides the document’s file URL as the reader’s source. ## Topics ### Reading a document [`read(from:progress:)`](/documentation/SwiftUI/DocumentReader/read(from:progress:)) Reads the document’s content from disk. [`Snapshot`](/documentation/SwiftUI/DocumentReader/Snapshot) The type representing the document’s content after reading. [`Source`](/documentation/SwiftUI/DocumentReader/Source) The type of the source location to read from. ## Relationships ### Conforming Types [`FileWrapperDocumentReader`](/documentation/SwiftUI/FileWrapperDocumentReader) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)