---
title: "supportedServiceSources(for:completionHandler:)"
framework: fileprovider
role: symbol
role_heading: Instance Method
path: "fileprovider/nsfileproviderservicing/supportedservicesources(for:completionhandler:)"
---

# supportedServiceSources(for:completionHandler:)

Asks the File Provider extension for an array of custom communication channels.

## Declaration

```swift
func supportedServiceSources(for itemIdentifier: NSFileProviderItemIdentifier, completionHandler: @escaping ([any NSFileProviderServiceSource]?, (any Error)?) -> Void) -> Progress
```

## Parameters

- `itemIdentifier`: The item’s identifier.
- `completionHandler`: A block that you call after gathering the service sources. You pass the following parameters:

## Return Value

Return Value An item that tracks the progress of the

## Discussion

Discussion The system calls this method when an app requests a list of supported services. Return an array of services for the specified file. An application with access to the file can request the supported services by calling the FileManager class’s getFileProviderServicesForItem(at:completionHandler:) method. For more information, see NSFileProviderService.