ImageStore

ImageStore is image downloader with memory cache supporting.

Example

To run the example project, clone the repo, and run pod install from the Example directory first.

Requirements

• Swift3.2
• iOS10.0 or higher
• cocoapods 1.4.0 or higher

Installation

ImageStore is available through CocoaPods. To install it, simply add the following line to your Podfile:

pod "ImageStore"

Classes, Structs, extensions

ImageStoreConfig

ImageStore's config struct.

property

• maxDownloadSize
  Max download size at one image. (default 2MB)

• cacheLimit
  Cache size. (default 200MB)

methods

• init(maxDownloadSize: Int64, cacheLimit: Int64)

ImageStore

Image downloader class.

property

• shared: ImageStore (static)
  Singleton shared instance.

• config: ImageStoreConfig
  ImageStore's config.

• completionsByURLString: [String: [ImageStoreCompletionHandler]]
  Completion handlers dictionary indexed by source URL String.

• downloadTaskByURLString: [String: URLSessionDownloadTask]
  Download task dictionary indexed by source URL String.

• cache: NSCache<AnyObject, UIImage>
  Image cache.

• queue: OperationQueue
  Image download queue.

• session: URLSession
  Image download URLSesson.

methods

• reset(config: ImageStoreConfig) (class)
  Create new shared instance from ImageStoreConfig.

• load(_ url: URL, completion: ImageStoreCompletionHandler?)
  Download image from URL, and execute CompletionHandler. If cached, only execute CompletionHandler.
  If download task has suspended, resume it.
  

let url = URL(string: "your.images.com/0.jpg")

ImageStore.shared.load(url) { [weak self] image in
    self?.myImageView.image = image
}

ImageStore.shared.load(url) { [weak self] image in
    self?.mySecondImageView.image = image
}

If you write like this, only one download task is create. But two completion handlers are executed.

• suspendIfResuming(url: URL)
  If ImageStore has download task with argument URL and it resuming, suspend it.
  You can resume it load(url) function.

• cancel(url: URL)
  Remove download task with argument URL.

UIImageView+ImageStore

UIImageView extension for using ImageStore.

methods

• load(_ url: URL, placeholderImage: UIImage?, shouldSetImageConditionBlock: @escaping (() -> Bool))
  Second argument shoulSetImageConditionBlock is closure that returns a condition allow ImageView to display image.
  It needs for resusable view (e.g. UITableViewCell, UICollectionViewCell).
  When reused thats views, you may change iamge of cell's ImageView.
  You must call suspendIfResuming(url: URL) or cancel(url: URL) at cell's prepareForReuse function.
  But suspendIfResuming(url: URL) and cancel(url: URL) does not delete completion handler for resume or next downloading.
  So if executed completion handler between after prepareForReuse and next download image completion handler, previous image has displayed till call next download is end.
  Look follow example.

class MyTableViewCell: UITableViewCell {
    static let cellIdentifier = "MyTableViewCell"
    var id: String?
    var myImageView: UIImageView = UIImageView()

    override func prepareForReuse() {
        super.prepareForReuse()
        id = nil
        myImageView.image = nil
        myImageView.suspendLoading()
    }
}

class MyListViewController: UIViewController, UITableViewDataSource {
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: MyTableViewCell.cellIdentifier, for: indexPath) as? MyViewCell else { return UITableViewCell() }
        let url = urls[indexPath.row]
        let urlString = url.absoluteString
        cell.id = urlString
        cell.myImageView.load(url) {
            // display image if cell's id and loading image url string is match.
            return cell.id == urlString
        }

        return cell
    }
}

• cancelLoading()
  Cancel current url loading.

• suspendLoading()
  Suspend current url loading.

Author

miup, [email protected]

License

ImageStore is available under the MIT license. See the LICENSE file for more info.

Contribution

• If you found a bug, please open an issue.
• I'm wating for your feature request, pelase open an issue.
• I'm wating for your contribution, please create a new pull request.