Loading Live Photos

Load and cache Live Photos from network sources using Kingfisher.

Overview

Kingfisher provides a seamless way to load Live Photos, which consist of a still image and a video, from network sources. This guide will walk you through the process of utilizing Kingfisher's Live Photo support.

Live Photo Data Preparation

Before loading a Live Photo with Kingfisher, you need to prepare and host the data. Kingfisher can download and cache the live photo data from the network (usually your server or a CDN). This section demonstrates how to get the necessary data from a PHAsset.

If you've already set up the data and prepared the necessary URLs for the live photo components, you can skip to the next section to learn how to load it.

Assuming you have a valid PHAsset from the Photos framework, here's a sample of how to extract its data:

let asset: PHAsset = // ... your PHAsset
if !asset.mediaSubtypes.contains(.photoLive) {
    print("Not a live photo")
    return
}

let resources = PHAssetResource.assetResources(for: asset)
var allData = [Data]()

let group = DispatchGroup()
group.notify(queue: .main) {
    allData.forEach { data in
        // Upload data to your server
        serverRequest.upload(data)
    }
}

resources.forEach { resource in
    group.enter()
    var data = Data()
    PHAssetResourceManager.default().requestData(for: resource, options: nil) { chunk in
        data.append(chunk)
    } completionHandler: { error in
        defer { group.leave() }
        if let error = error {
            print("Error: \(error)")
            return
        }
        allData.append(data)
    }
}

Important notes:

This is a basic example showing how to retrieve data from a live photo asset.
Use PHAssetResource.type to get more information about each live photo resource. Typically, resources with .photo and .pairedVideo types are necessary for a minimal Live Photo.
Do not modify the metadata or actual data of the resources, as this may cause problems when loading in Kingfisher later.
When serving the files, it's recommended to include the file extensions (.heic for the still image, and .mov for the video) in the URL. While not mandatory, this helps Kingfisher identify the file type more accurately.
You can use PHAssetResource.originalFilename to get and preserve the original file extension.