I've seen that you can download an image in IOS through a URL. However, this requires that the URL be public. I'd much rather do it in such a way where my application makes a request to the server and if the necessary requirements are met, the server responds with an image. I do not want my images to be visible from the web.
The easiest option is to put the password in the URL:
let url = NSURL(string: "http://exapmle.com/2XwLZAgAO2VP9JqXg1s73zmB/foo.png")
let dataOptional: NSData? = NSData(contentsOfURL: url)
if let data = dataOptional {
let image = UIImage(data: data)
} else {
println("Error loading \(url)")
}
Related
This question already has answers here:
Loading/Downloading image from URL on Swift
(39 answers)
Closed 5 years ago.
EDIT 3: Please also read my comment in the "answered" tagged answer. I think I won't use my synchronous method but change to the suggested asynchronous methods that were also given!
Ok I am struggling with some basic concepts of showing images from an URL from the internet on my app.
I use this code to show my image on an UIIamgeView in my ViewController:
func showImage() {
let myUrlImage = URL(string: linkToTheImage)
let image = try? Data(contentsOf: myUrlImage!)
imageView1.image = UIImage(data: image!)
}
Now basically I have the following question:
Is the whole image downloaded in this process?
Or works the UIImageView like a "browser" in this case and doesn't download the whole picture but only "positions" the image from the URL into my UIImageView?
EDIT:
The reason I asked is, I am basically doing a quiz app and all I need in the view is an image from a URL for each question - so it's no difference if I do it asynchronous or synchronous because the user has to wait for the image anyways. I am more interested in how do I get the fastest result:
So I wanted to know if my code really downloads the picture as a whole from the URL or just "Positions" it into the UIImageView?
If in my code the picture is downloaded in its full resolution anyways, then you are right, I could download 10 pictures asynchronously when the player starts the quiz, so he hopefully doesn't have to wait after each answer as long as he would wait when I start downloading synchronously after each answer.
Edit 2:
Because my Question was tagged as similar to another some more explanation:
I already read about synchronous and asynchronous downloads, and I am aware of the downsides of synchronous loading.
I am more interested in a really basic question, and I get the feeling I had one basic thing really wrong:
My initial thought was that if I open a link in my browser, for example this one,
https://cloud.netlifyusercontent.com/assets/344dbf88-fdf9-42bb-adb4-46f01eedd629/68dd54ca-60cf-4ef7-898b-26d7cbe48ec7/10-dithering-opt.jpg
the browser doesn't download the whole picture. But I guess this isn't the case? The whole picture is downloaded?
Never use Data(contentsOf:) to display data from a remote URL. That initializer of Data is synchronous and is only meant to load local URLs into your app, not remote ones. Use URLSession.dataTask to download image data, just as you would with any other network request.
You can use below code to download an image from a remote URL asynchronously.
extension UIImage {
static func downloadFromRemoteURL(_ url: URL, completion: #escaping (UIImage?,Error?)->()) {
URLSession.shared.dataTask(with: url) { data, response, error in
guard let data = data, error == nil, let image = UIImage(data: data) else {
DispatchQueue.main.async{
completion(nil,error)
}
return
}
DispatchQueue.main.async() {
completion(image,nil)
}
}.resume()
}
}
Display the image in a UIImageView:
UIImage.downloadFromRemoteURL(yourURL, completion: { image, error in
guard let image = image, error == nil else { print(error);return }
imageView1.image = image
})
You can do it this way. But in most cases it is better to download the image first by yourself and handle the displaying then (this is more or less what the OS is doing in the background). Also this method is more fail proof and allows you to respond to errors.
extension FileManager {
open func secureCopyItem(at srcURL: URL, to dstURL: URL) -> Bool {
do {
if FileManager.default.fileExists(atPath: dstURL.path) {
try FileManager.default.removeItem(at: dstURL)
}
try FileManager.default.copyItem(at: srcURL, to: dstURL)
} catch (let error) {
print("Cannot copy item at \(srcURL) to \(dstURL): \(error)")
return false
}
return true
}
}
func download() {
let storagePathUrl = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as NSString).appendingPathComponent("image.jpg")
let imageUrl = "https://www.server.com/image.jpg"
let urlRequest = URLRequest(url: URL(string: imageUrl)!)
let task = URLSession.shared.downloadTask(with: urlRequest) { tempLocalUrl, response, error in
guard error == nil, let httpResponse = response as? HTTPURLResponse, httpResponse.statusCode == 200 else {
print("error")
return
}
guard FileManager.default.secureCopyItem(at: tempLocalUrl!, to: storagePathUrl) else {
print("error")
return
}
}
task.resume()
}
let url = URL(string: (pinsFIREBASE[marker.snippet!]?.imageURL)!)
let task = URLSession.shared.dataTask(with: url!) { data, response, error in
guard let data = data, error == nil else { return }
DispatchQueue.main.async() {
self.postImage.image = UIImage(data: data)
}
}
task.resume()
I have the following code that takes a url from firebase, in the form http://i.imgur.com/nkomPpP.jpg, and is supposed to turn that url into a UIImage that can be placed on a view. However, while extracting the text from the firebase object works, parsing the image URL doesn't seem to be working as I get an empty view. What am I doing wrong?
I know why, your code works. The problem is your image link. Your imageURL's HTTP type. iOS don't like HTTP type request because it's not safe.
Plan A: Try a HTTPS type image link, it works.
Plan B: Add "App Transport Security Settings" in project info ,and set "Allow
Arbitrary Loads" yes in "App Transport Security Settings" dictionary.
I suggested use Plan A, that's Apple want iOSDev to do.
You need to remove the () from after DispatchQueue.main.async(). Try this:
let url = URL(string: (pinsFIREBASE[marker.snippet!]?.imageURL)!)
let task = URLSession.shared.dataTask(with: url!) { data, response, error in
guard let data = data, error == nil else { return }
DispatchQueue.main.async {
self.postImage.image = UIImage(data: data)
}
}
task.resume()
This question already has answers here:
Transport security has blocked a cleartext HTTP
(29 answers)
Closed 6 years ago.
When I try to load an image from a URL I always get an error despite the fact that I know that there is a URL that contains a valid .jpg image.
mainImageView.image = try UIImage(data: Data(contentsOf: URL(fileURLWithPath: artworkURL)))
I also tried these solution but the line where I initialise the UIImage still throws an error.
Example of data in artworkURL:
http://is1.mzstatic.com/image/thumb/Music/v4/ef/97/95/ef979538-8321-151a-dceb-9b0a7f7c7641/source/100x100bb.jpg
Current solutions do not solve my problem. I also tried:
try UIImage(data: Data(contentsOf: URL(string: artworkURL)!))
and
try UIImage(data: Data(contentsOf: (URL : artworkURL)))
and (fuller code) now using a static url to debug
let artworkString = "http://is1.mzstatic.com/image/thumb/Music/v4/ef/97/95/ef979538-8321-151a-dceb-9b0a7f7c7641/source/100x100bb.jpg" // album.artworkURL[index.row]
let url = URL(string: artworkString)
do {
mainImageView.image = try UIImage(data: Data(contentsOf: url!))
} catch _ {
print("No album artwork!")
}
This last one outputs "No album artwork!"!
You can user this library:
https://github.com/onevcat/Kingfisher
Kingfisher is a lightweight, pure-Swift library for downloading and caching images from the web. This project is heavily inspired by the popular SDWebImage. It provides you a chance to use a pure-Swift alternative in your next app.
let imagePath = URL(string: "url_of_your_image")
imageView.kf_setImageWithURL(NSURL(string: imagePath)!, placeholderImage: UIImage(named: "placeholder"))
you can also add placeholder image.
Is there a way to download couple of files (images) using Firebase Storage SDK and live cache those files, so after an image is downloaded the cache is updated?
Can I also observe in another view controller for this cache being updated?
I don't need a whole answer, just maybe a hint where to learn it. I've search through firebase documentation, found some info but I have absolutely no idea how to use it.
Take a look at NSURLCache. Basically what you'll do is, every time you upload a file to Firebase Storage, you can get a download URL and download it, then storeCachedResponse:forRequest: in the URL cache. Since this cache is shared, you can even grab it across activities.
Similarly, on download, you'll want to check for the cached request via cachedResponseForRequest: and if it doesn't exist, perform the download (at which point you cache the request for later).
Long term, we're hoping to enable this behavior for you out of the box, but for now, you can use NSURLCache to make it happen :)
I still haven't found a way to do this from within the Firebase Storage SDK. Here is some code I got off bhlvoong tutorials to cache images using NSCache.
import UIKit
let imageCache = NSCache<AnyObject, AnyObject>()
extension UIImageView {
func loadImageUsingCacheWithUrlString(urlString: String) {
self.image = nil
//check cache for image first
if let cachedImage = imageCache.object(forKey: urlString as NSString) as? UIImage {
self.image = cachedImage
return
}
//otherwise fire off a new download
let url = NSURL(string: urlString)
URLSession.shared.dataTask(with: url as! URL, completionHandler: { (data, response, error) in
//download hit an error so lets return out
if error != nil {
print(error)
return
}
DispatchQueue.main.async {
if let downloadedImage = UIImage(data: data!) {
imageCache.setObject(downloadedImage, forKey: urlString as NSString)
self.image = downloadedImage
}
}
}).resume()
}
}
I just need to upload some images, and I feel like my simple code should work, but for some reason it isn't. I'm getting an error saying that my object exceeds the Parse.com limit of 128kb... And I'm sure it doesn't actually exceed that. Code is here.
override func viewDidLoad() {
super.viewDidLoad()
func addCards(urlString:String) {
var newCard = PFObject(className: "Cards")
let url = NSURL(string: urlString)
let urlRequest = NSURLRequest(URL: url!)
NSURLConnection.sendAsynchronousRequest(urlRequest, queue: NSOperationQueue.mainQueue(), completionHandler: {
response, data, error in
newCard["image"] = data
newCard.save()
})
}
addCards("http://image.com/image")
You shouldn't just be pushing the image data direct into the object. Instead, create a PFFile instance with the data and set that. Then, save the file and the card at the same time (using saveAll).
See the following link from Parse documentations which has a code snippet and also the reason for using PFFile as suggested by Wain:
https://www.parse.com/docs/ios/guide#files
According to Parse documentation: You can easily store images by converting them to NSData and then using PFFile. Suppose you have a UIImage named image that you want to save as a PFFile:
let imageData = UIImagePNGRepresentation(image)
let imageFile = PFFile(name:"image.png", data:imageData)
var userPhoto = PFObject(className:"UserPhoto")
userPhoto["imageName"] = "My trip to Hawaii!"
userPhoto["imageFile"] = imageFile
userPhoto.saveInBackground()