swift - Converting Array of URLs into Array of UIImage -


i have array of urls linking image files, how store them array of uiimages?

var imagesarray = [uiimage]()  let links = ["http://example.com/image1.jpg","http://example.com/image2.jpg"] [string]

there must easy solution. if 1 image following:

let url = url(string: link2image!)! let imagedata = try? data(contentsof: url) let image = uiimage(data: imagedata!)! self.image.append(image)

the easiest solution iterate through array , download images synchronously using data(contentsof:), however, quite insufficient due synchronous execution.

let images = links.flatmap{ link->uiimage? in     guard let url = url(string: link) else {return nil}     guard let imagedata = try? data(contentsof: url) else {return nil}     return uiimage(data: imagedata) }

a better solution download images asynchronously in parallel, have written uiimage extension using promisekit:

extension uiimage {     class func downloadedasync(fromurl url: url)->promise<uiimage> {         return promise{ fulfill, reject in             urlsession.shared.datatask(with: url, completionhandler: { data, response, error in                 guard let data = data, error == nil else {                     reject(error!); return                 }                 guard let httpresponse = response as? httpurlresponse, httpresponse.statuscode == 200 else {                     reject(nserror(domain: "wrong http response code when downloading image asynchronously",code: (response as? httpurlresponse)?.statuscode ?? 1000));return                 }                 guard let mimetype = response?.mimetype, mimetype.hasprefix("image"), let image = uiimage(data: data) else {                     reject(nserror(domain: "no image in response", code: 700)); return                 }                 fulfill(image)             }).resume()         }     } }

you call array of links this: 

var imagedownloadtasks = links.flatmap{ link in     guard let url = url(string: link) else {return nil}     return uiimage.downloadedasync(fromurl: url) }

then execute promises:

when(fulfilled: imagedownloadtasks).then{ images in     //use images, images of type [uiimage] }

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