Is it possible to edit the url of an image before cache it by SDWebImage?

Question

I am using S3 image url. It contains a secret key part. I am using SDWebImage to load the images. I want to cache the images, but due to the signature change from the S3, I am not able to cache the image(due to signature change all image urls are deferent). Is it possible to cache the image without this signature in the url?

score 3 · Accepted Answer · answered Jul 16 '20 at 05:35

I got the answer for this. SDWebImage providing download with out caching and caching with a key. As per my requirement, this is enough.

First set the cache key for caching image.
Then, check the image is available with that cache key.
If not available, then download and cache that image with key.

Once cached it will be available on the next checking of cache availability. So no need to cache the image multiple times.

extension UIImageView {

func setImage(imageUrlString: String) {
    
    let sdManager = SDWebImageManager.shared
    let sdDownloader = SDWebImageDownloader.shared
    let sdChache = SDImageCache.shared
    var cacheKey: String?
    let placeholderimage = UIImage(named: "placeholder.png")
    
    guard let imageURL = URL(string: imageUrlString) else {
        self.image = placeholderimage
        return
    }
    guard let key = sdManager.cacheKey(for: imageURL) else {return}// set the key you want. In the case of s3 images you can remove the signature part and use the remainig url as key, beacause it's unique.
    cacheKey = key
    if let key = cacheKey {
        if let cachedImage = sdChache.imageFromCache(forKey: key) {
            self.image = cachedImage
        }
        else {
            self.sd_imageIndicator = SDWebImageActivityIndicator.gray
            self.sd_imageIndicator?.startAnimatingIndicator()
            sdDownloader.downloadImage(with: imageURL) { (downloadedImage, imageData, error, status) in
                self.sd_imageIndicator?.stopAnimatingIndicator()
                if let image = downloadedImage, let data = imageData {
                    self.image = image
                    self.sd_imageIndicator?.stopAnimatingIndicator()
                    sdManager.imageCache.store(image, imageData: data, forKey: key, cacheType: .all) {
                        print("Image Cached with key==> \(key)")
                    }
                }
                else{
                    self.image = placeholderimage
                }
            }
        }
    }
}

}

Is it possible to edit the url of an image before cache it by SDWebImage?

1 Answers1