LinkPreviewSwift is an in-progress implementation of link previews in Swift that works client-side or server-side.
Similarly to the LinkPresentation framework, you create an instance of LinkPreviewProvider
that you can configure to load link previews for you.
let provider = LinkPreviewProvider()
// Optionally, configure the provider:
// Turn off processing that requires making additional requests for more information,
// instead choosing only to read data from the single page that's loaded.
provider.options.allowAdditionalRequests
// Load the preview
let preview = try await provider.load(from: url)
// You can also provide custom headers to attach to the request
let preview = try await provider.load(from: url, headers: [
"Authorization": "Bearer ..."
])
// You can also load directly from HTML
let html = "<html><head><title>Title</title></head></html>"
let preview = try await provider.load(html: html, url: URL(string: "example.com")!)The LinkPreview type has several accessors for common OpenGraph metadata:
let imageURL = preview.imageURL
let title = preview.title
let description = preview.descriptionBut you can also read custom OpenGraph fields directly from the properties:
// Parses `og:image`, `og:image:width`, and `og:image:height` tags.
let imageURLProperty = preview.property(named: "image")
let imageURL = imageURLProperty.content
if let width = imageURLProperty.metadata["width"],
let height = imageURLProperty.metadata["height"] {
// Parse size as integers.
}By default all the extraction is performed by MetadataProcessor objects. There
are currently three, OpenGraphProcessor, GenericHTMLProcessor, and
WikipediaAPIProcessor, the latter of which is specific to wikipedia.org URLs.
You can implement your own processor to recognize special pages and perform more
specific scraping tasks; you will be handed a Document from SwiftSoup
that you can extract data from.
For example, you can add a processor that adds the URL to the end of the title like so:
enum CustomProcessor: MetadataProcessor {
static func updateLinkPreview(
_ preview: inout LinkPreview,
for url: URL,
document: Document?,
options: MetadataProcessingOptions
) async {
let title = preview.title ?? ""
if let host = url.host {
if !title.isEmpty {
title += " • "
}
title += host
}
if !title.isEmpty {
preview.title = title
}
}
}
// Tell the provider to run this processor along with the others.
provider.registerProcessor(CustomProcessor.self)
let preview = try await provider.load(from: URL(string: "https://example.com")!)
print(preview.title) // prints 'Example Domain • example.com'LinkPreviewSwift can be added to your project using Swift Package Manager. For more information on using SwiftPM in Xcode, see Apple's guide
If you're using package dependencies directly, you can add this as one of your dependencies:
dependencies: [
.package(url: "https://github.com/harlanhaskins/LinkPreviewSwift.git", branch: "main")
]Harlan Haskins (harlan@harlanhaskins.com)