---
title: "read(from:)"
framework: uikit
role: symbol
role_heading: Instance Method
path: "uikit/uidocument/read(from:)"
---

# read(from:)

Reads the document data in a file at a specified location in the application sandbox.

## Declaration

```swift
func read(from url: URL) throws
```

## Parameters

- `url`: A file URL that identifies the location of the document file in the application sandbox. This file URL is typically the one returned by the doc://com.apple.uikit/documentation/UIKit/UIDocument/fileURL property.

## Discussion

Discussion Typical UIDocument subclasses shouldn’t need to call this method directly, especially if the entire file is read at once. The default implementation calls load(fromContents:ofType:) on the queue on which open(completionHandler:) was called to provide the UIDocument subclass with the document data object. Subclasses that want more control over the reading of the document file—for example, that want to read a large document file incrementally—can override this method. It isn’t necessary for these subclasses to call the superclass implementation (super). note: In Swift, this method is marked with the throws keyword to indicate that it throws an error in cases of failure. When overriding this method, use the throw statement to throw an NSError, as described in Error Handling in The Swift Programming Language and About Imported Cocoa Error Parameters.

## See Also

### Reading document data

- [open(completionHandler:)](uikit/uidocument/open(completionhandler:).md)
- [load(fromContents:ofType:)](uikit/uidocument/load(fromcontents:oftype:).md)