AWS socket S3存储桶中的缓存

Question

我的要求是“我有一个从亚马逊s3存储桶下载图片的应用程序。我需要缓存这些图片，我使用了普通的缓存。但我需要实现与SDWebImage相同的缓存技术”。SDWebImage中缓存方法的工作原理。

Answer 1

创建一个缓存并将image设置为url字符串，并通过检查缓存中是否有该对象来从任何地方分配它

  let imageCache = NSCache<AnyObject, AnyObject>()

  imageCache.setObject(imageToCache!, forKey: urlString as AnyObject)

  if let imageFromCache = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
     self.image = imageFromCache
     return
  }

Answer 2

非常方便的UIImageview图像缓存扩展。

import UIKit

let imageCache = NSCache<AnyObject, AnyObject()

extension UIImageView {
  func cacheImage(urlString: String){
    let url = URL(string: urlString)

    image = nil

    if let imageFromCache = imageCache.object(forKey: urlString as AnyObject) as? UIImage {
        self.image = imageFromCache
        return
    }

    URLSession.shared.dataTask(with: url!) {
        data, response, error in
          if let response = data {
              DispatchQueue.main.async {
                  let imageToCache = UIImage(data: data!)
                  imageCache.setObject(imageToCache!, forKey: urlString as AnyObject)
                  self.image = imageToCache
              }
          }
     }.resume()
  }
}