I have a NSViewController which displays various WKWebView at specific locations inside a NSView. If the frame of the WKWebView gets small - it switches to the mobile version of the website. Is there a way to always show the full (desktop version) website in the WKWebView?
My first idea was to inject some javascript and set the viewport to a specific size to force the website to display a "Desktop" view.
let viewportScriptString = "var meta=document.createElement('meta');meta.name=\"viewport\";meta.content=\"width=1920\";document.getElementsByTagName('head')[0].appendChild(meta);"
let viewportScript = WKUserScript(source: viewportScriptString, injectionTime: .AtDocumentStart, forMainFrameOnly: true)
let controller = WKUserContentController()
controller.addUserScript(viewportScript)
let config = WKWebViewConfiguration()
config.userContentController = controller
let nativeWebView = WKWebView(frame: CGRect.zero, configuration: config)
Unfortunately this does not work and the website is still scaled. To demonstrate the behaviour i try to achieve please see the following screenshot.
==EDIT==
thanks for pointing me to some similar questions. I tried the following the solutions that worked for other users. Unfortunately I had no luck. Maybe WKWebView is different on macOS - the other questions are about iOS.
NSUserDefaults
setting the CustomUserAgent on WKWebView
setting ApplicationNameForUserAgent on WKWebViewConfiguration
adding a User-Agent to NSUrlRequest
You should change the user agent, for example:
UserDefaults.standard.register(defaults: ["UserAgent" : "Chrome Safari"])
Apple's recommendation:
In apps that run in iOS 8 and later, use the WKWebView class instead of using UIWebView.
Thus, I have replaced my good old UIWebView with a shiny new WKWebView. But what I thought to be an easy exercise (simply swapping the classes and replacing the delegate methods) turned out to be a real mess.
The Problem
When I load an HTML string using
loadHTMLString(String, baseURL: URL?)
the web view loads and renders the pure HTML but it doesn't load any images or CSS files referenced inside the htmlString.
This happens only on a real device!
In Simultor all referenced resources are loaded correctly.
Example
I have defined a simple htmlString in my view controller class:
let imageName = "image.png"
let libraryURL: URL // The default Library URL
var htmlString: String {
return "<html> ... <img src=\"\(imageName)\" /> ... </html>"
// "..." represents more valid HTML code incl. header and body tags
}
The image is stored in the root Library folder so its URL is:
let imageURL = libraryURL.appendingPathComponent(imageName)
Now I load the htmlString into the web view:
webView.loadHTMLString(htmlString, baseURL: libraryURL)
and it doesn't load the image even though the baseURL is set correctly.
Ideas for a Solution
Maybe WKWebView has a problem with resolving relative paths so my first idea was to use absolute paths inside the HTML string instead.
→ ❌ Doesn't work.
Two answers to another SO post suggested that using
loadFileURL(URL, allowingReadAccessTo: URL)
instead of loadHTMLString(...) works in iOS 9+.
→ ✅ That works.
However, I cannot use solution 2 because my HTML files are encrypted and the decrypted files must not be stored on the disk.
Question
Is there any way to load local resources like images and styles using the WKWebView's
loadHTMLString(String, baseURL: URL?)
function? Or is still a bug in iOS 9+?
(I just cannot believe that Apple provides and recommends using a web view that cannot load any local web content from inside an HTML string?!)
Without taking a look at your actual project it's difficult to give some hundreed percent sure advices.
However:
class ViewController: UIViewController {
var webView = WKWebView()
override func viewDidLoad() {
super.viewDidLoad()
webView.translatesAutoresizingMaskIntoConstraints = false
let views = [
"webView" : webView
]
view.addSubview(webView)
var constraints = NSLayoutConstraint.constraintsWithVisualFormat("H:|[webView]|", options: [.AlignAllLeading, .AlignAllTrailing], metrics: nil, views: views)
constraints.appendContentsOf(NSLayoutConstraint.constraintsWithVisualFormat("V:|[webView]|", options: [.AlignAllTop, .AlignAllBottom], metrics: nil, views: views))
NSLayoutConstraint.activateConstraints(constraints)
let path = NSBundle.mainBundle().pathForResource("ios - WKWebView fails to load images and CSS using loadHTMLString(_, baseURL_) - Stack Overflow", ofType: "htm")
let url = NSURL(fileURLWithPath: path!)
webView.loadHTMLString(try! String(contentsOfURL: url), baseURL: url.URLByDeletingLastPathComponent)
// Do any additional setup after loading the view, typically from a nib.
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
}
I think the key point here is baseUrl parameter, you should setup it correctly. In my case i've used html's url without last path component - e.g. containing folder. This works fine on both device & simulator - check device snapshot. I've uploaded sample project to https://github.com/soxjke/WKWebViewTest so you can take a look (i've removed codesigning info from git)
So, to recap - method is working, functionality is working, just you do something wrong with it. To help you get what's wrong with your solutions, i'll add some suggestions:
1. Remember, that simulator filesystem is case-insensitive, device filesystem is case-sensitive. So if you have your filenames in html in lowercase - this won't work on device. 8fFsD.png != 8ffsd.png
2. Remember, that when copying resources, XCode ignores your folder structure. So if your html has <img src="./img/1.png"> and your XCOde project has folder structure like
test.htm
img/
1.png
2.png
After build it will be flattened, so test.htm and 1.png and 2.png will reside on same level
test.htm
1.png
2.png
I'm almost sure, after you verify these two assumptions, you'll get this method working.
I had this problem today, I've found the solution and potentially the cause:
loadHTMLString(String, baseURL: URL?)
This function doesn't allow the rendered HTML to access local media, as far as I'm aware, this is because it would be an injection risk, this could allow rendered HTML to access and manipulate your local file system. With a html string, that could come from anywhere or anyone.
loadFileURL(URL, allowingReadAccessTo: URL)
With this function, you point the WKWebview to the html file in your FileManager, and to the containing folder with 'allowingReadAccessTo'. Because the html is stored within the FileManager, it will allow the rendered HTML to access locally stored media.
If you don't have the html file stored locally for some reason(I assume you do), You could write the html sting into a .html file, then point to the URL of that file. However, this is just subverting Apple's protection, so do it at your own peril (don't do it).
This is just the solution that worked for me and my understanding of why we're having the problem to begin with.
Edit #1: Typo.
Edit #2: I've since found another nuance, When stating the 'allowingReadAccessTo:' URL, if the HTML itself needs to access things in parent folders (ie: .css, .js files), you need to specify the parent folder, not necessarily the location of the HTML itself, this will then implicitly allow access to the child folders as required also. For me, this problem was only apparent on a physical device, this didn't seem to have an effect whilst running in simulator, likely another discrepancy between how permissions work on simulator and a physical device.
Personally, I had to switch to using XWebView as the out-of-the-box behavior of WKWebView does not allow loading of local files. XWebView tricks it by loading up a local web server in the background and directing local traffic thru it. (XWebView is based on top of WKWebView)
Seems a bit overkill, but that is what I ended up having to do.
I've been experimenting with this as well, with similar restrictions, and the problem appears to be that paths aren't resolved unless baseURL references the application bundle. It doesn't work if you, for example, have something in the application's documents.
Edit: I have filed a radar for this rdar://29130863
Well you should be able to use local images and CSS files (and JavaScript files for that matter) with WKWebViews with the function that you have already found. My guess is that the problem is with your baseURL variable.
Update 7.5.2017:
I have completely updated the code from another SO answer of mine that used to be linked to my answer here. I have a working project for loadHTMLString() and .loadFileURL()
Try to create baseURL using:
let baseURL = URL(fileURLWithPath: "#path#")
instead of:
let baseURL = URL(string: "#path#")
The main difference is that the first method adds file:// prefix before the path.
You can base64 encode the images... I know that works. Not sure if it will be appropriate for your use case though.
Kind of funny, I just ran into this problem while doing the opposite - moving from base64 encoded to image files.
When I used UIWebview, I used baseURL as,
let baseUrl = NSURL(string: Bundle.main.path(forResource: "cms", ofType: "html")!)! as URL
webView.loadHTMLString(bodyPage, baseURL: baseUrl)
But for the WKWebView, I used baseURL as
let baseUrl = Bundle.main.bundleURL
webView.loadHTMLString(bodyPage, baseURL: baseUrl)
This works for me.
I know this is quite old already, but I ran into the exact same problem and it took me hours of trials and even to find this thread with the same problem (Xamarin Forms App)
My issue was: parsing remote HTML content into a string and also adding locally saved images (also downloaded dynamically, no resource of the app). On the simulator all works well, but on acutal device the local images are not showing (also no ? or anything indicating an error, just a blank frame). The Xamarin webview also offers the "BaseURL" option which didn't help, also not to use the BaseURL on the custom iOS wkWebView.
The only working solution as pointed out by Scott above, is to write the HTML into a file and then use the "LoadFileUrl" function and allow read access to the base directory. This also works with absolute file paths for images in the HTML (not only relative to the basedir, but of course somewhere within the basedir).
My custom webview renderer to load web and local content looks like this now:
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e) {
base.OnElementPropertyChanged(sender, e);
NSUrl baseURL = new NSUrl(App.dirNews, true);
string viewFile = Path.Combine(App.dirNews, "view.html");
NSUrl fileURL = new NSUrl(viewFile, false);
switch (e.PropertyName) {
case "Url":
System.Console.WriteLine("--- Loading Web page ---");
System.Console.WriteLine("--- " + Element.Url + " ---");
NSUrlRequest myRequest = new NSUrlRequest(new NSUrl(Element.Url), NSUrlRequestCachePolicy.ReloadIgnoringLocalAndRemoteCacheData, 120);
Control.LoadRequest(myRequest);
break;
case "HTML":
System.Console.WriteLine("--- Showing HTTP content ---");
File.WriteAllText(viewFile, Element.HTML, System.Text.Encoding.UTF8);
Control.LoadFileUrl(fileURL, baseURL);
break;
}
}
I was able to reproduce a similar issue. WKWebView loads my images specially if they are located remotely, apart from my app server.
For servers that are not SSL-secured (http instead of https), you can set your info.plist as per below:
App Transport Security Settings
- Allow Arbitrary Loads in Web Content (Set to YES)
- Allow Arbitrary Loads (Set to YES)
The problem was actually in the server. The server application was either:
Changing the image src from "http://IP-or-domain/uploads/file.jpg" to "../../uploads/file.jpg"
- OR -
The image src was "http://localhost/uploads/file.jpg" or "http://127.0.0.1/uploads/file.jpg" instead of "http://YOUR-SERVER-IP-ADDRESS/uploads/file.jpg"
In these cases, the actual device wont be able to locate the image. This only works with iOS Simulator because the virtual device is the same as the server and development machine. It can read LOCALHOST and 127.0.0.1.
In my server, I was using a Rich Text Editor (TinyMCE) and it automatically removes the IP address after it detects that it's the same source.
WKWebView can load image or css file from NSTemporaryDirectory, so you can copy your files to NSTemporaryDirectory, and then load it. It works for me on iOS 14! see this issue. ios-wkwebview-loadhtmlstring-baseurl-fails-to-load-images-and-read-css
It took me a while to figure this out, but based on this answer I got it working:
https://stackoverflow.com/a/73519282/5868066
Try this:
let htmlPath = URL(fileURLWithPath: "")
let htmlDirectory = htmlPath.deletingLastPathComponent()
let htmlString = try! String(contentsOfFile: htmlPath.path, encoding: .utf8)
let baseURL = URL(fileURLWithPath: htmlDirectory)
let documentsDirectory = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[.zero]
webView.loadFileURL(htmlPath, allowingReadAccessTo: documentsDirectory)
webView.loadHTMLString(htmlString, baseURL: baseURL)
Im trying to load(and upload) images in my app(by picture path).
This is working in my simulator. everything works there. only when im trying to do this on the iphone itself it won't work and i see just the empty UIImageviews.
The paths are loaded the same as in the simulator. And originate from:
PHImageManager.defaultManager().requestImageDataForAsset(asset, options: nil)
{
imageData,dataUTI,orientation,info in
cell.setString(info["PHImageFileSandboxExtensionTokenKey"] as String,name:dataUTI as String)
}
And the PHImageFileSandboxExtentionTokenKey is split into the data and the url when loading the image.
this results in the simulator as :
/Users/Twizzler/Library/Developer/CoreSimulator/Devices/3E671415-8B83-44DA-870F-19BF2BC11F8F/data/Containers/Data/Application/8872109F-3784-40EB-BEB6-4E9FDABE013D/Documents/1613945_10200645161051698_4122753901212984922_n.jpg
and in the iphone as:
/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG
Im loading the image like this:
let image = UIImage(named: "/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG")
cell.imageView.image = image
in this case i put the image url hardcoded (this is in the final app an array of images)
I don't get an error or stack trace. When placeing a breakpoint im seeing the image information in the same way as the simulator
as suggested by the answer im now trying to load them as follows:
let image = UIImage(contentsOfFile: "/private/var/mobile/Media/DCIM/102APPLE/IMG_2607.JPG")
cell.imageView.image = image
This isn't working and i can't upload the files
That’s not how imageNamed works—as the documentation states, that looks for an image with the given name inside your app’s bundle. Try imageWithContentsOfFile.
Well i fixed it! after some puzzling days im now using this way to access upload and
cell.imageView.image = UIImage(data: array[indexPath.row][0] as NSData)
This shows the image. I can save the NSData in the CoreData and reload the image on this way.
To lighten the load on the system im using this:
cellData.checked = 1
var imageData = UIImageJPEGRepresentation(cell.imageView.image, 1)
self.array.append([imageData,cellData.imageData] )
let myObj : ViewControllerImagePicker = self.parentViewController as ViewControllerImagePicker
let textfield: UILabel = myObj.amountLabel! as UILabel
textfield.text = String(self.array.count )
cell.textLabel.alpha = 1
this code is being called when there is clicked on a cell. by setting the cellData.imageData i can recall the cells (when clicking back to the collection view)
I do not know if the way im doing it is correct or works with more that 10 files because of data usage problems. But in my case with a max of 6 selected pictures it works like a charm
The simulator works completely different than a real device when it comes to files, the app bundle and sandboxing.
For starters the simulator will let you write to and add or change files in your app bundle. iOS running on a real device won't let you do this.
You can't hardcode any paths in your app. Even if it works today or on your device in test mode that doesn't mean it will work on a released version. And even if it does it could stop working on any update. Apple several times has changed where things are stored and the path structure in the phone. And where you are allowed to write.
Make bundle calls to get the path locations of standard folders.
Use the assets library to load images from the photo library, or to save them there.
There are tons of resources and tutorials online on how to do this.
I am having some issues when trying to run my app on an iPad (or any device) it runs as expected on the emulator so it is weird that it doesn't work on a device. I was wondering if some one could point me in the correct direction. I spend many hours reading all the other posts on here about the same issues, however none of the suggested solutions worked.
I have a WKWebView into which I am loading a local html file. On the emulator the file loads and everything works fine but on a device I am getting a message in the log:
Could not create a sandbox extension for '/'
Here is the code I have that loads the file into the
override func viewDidLoad() {
super.viewDidLoad()
var path = NSBundle.mainBundle().pathForResource("Login_UK",
ofType: "html")
var url = NSURL(fileURLWithPath: path!)
var request = NSURLRequest(URL: url!)
var theConfiguration = WKWebViewConfiguration()
theConfiguration.userContentController.addScriptMessageHandler(self,
name: "callbackHandler")
webView = WKWebView(frame: self.view.frame,
configuration: theConfiguration)
webView!.loadRequest(request)
self.view.addSubview(webView!)
}
Any help will be greatly appreciated
Kind Regards,
Dimitar
Thank you for any one who tried to answer my question. I have released that this is an error with the WebKit lib that Apple are trying to fix. However I have found a good workaround that required little work.
I open the local file and read its content and then send that string into a webView.loadHTMLString method that compiles the hmtl that was in the file. That way you avoid the issues with iOS not being able to find the path to the local file.
Here is an example of reading a file and then opening it for any one who has the same issues:
let path2 = NSBundle.mainBundle().pathForResource("index", ofType: "html")
var text = String(contentsOfFile: path2!, encoding: NSUTF8StringEncoding, error: nil)!
webView!.loadHTMLString(text, baseURL: url)
Kind regards,
Dimitar
Just do this:
if url.isFileURL {
webView.loadFileURL(url, allowingReadAccessTo: url)
} else {
let request = URLRequest(url: url)
webView.load(request)
}
There is a function loadFileURL on the WKWebView starting iOS 9 that apparently has to be used when reading data from a file URL.
Strange enough using the load function with an URLRequest for the file URL does work in the simulators, but not on device - the web view stays blank on the device. Using the loadFileURL works on device and the simulator.
Using loadHTMLString unfortunately introduces another problem (local anchors that jump to another position in the same web view are not working anymore) and probably should be avoided until Apple releases a fix for that issue.
Actually the problem is caused by the webView.load() function, if we test it on simulators it will work perfectly, but for the real device it may cause some problems and it will not load the webview perfectly. You may check it by calling the didFinish() function.
What you need to do is call webView.loadFileURL() rather than webView.load(). It will work in both simulators and real devices. This is very useful when you load any file from the local file directory.
i use htm file for some work in program. in simulator i defined local file like this ;
var a = dic["acil_adi"]?.asString()
var path = NSBundle.mainBundle().pathForResource(a,
ofType: ".htm")
var url = NSURL(fileURLWithPath:path!)
var request = NSURLRequest(URL:url)
println("\(url)")
var theWebView:WKWebView = WKWebView(frame:self.view.frame)
theWebView.loadRequest(request)
self.view.addSubview(theWebView)
but when i send this app to device (iPhone 5s)
error appears :
file:///private/var/mobile/Containers/Bundle/Application/2E9F7BCA-D57E-4C47-8BBC-6CBF2FF2B2E1/Receteler.app/Akciger_odemi_Akut_Kalp_Yetmezligi.htm
Could not create a sandbox extension for '/'
this is my htm files folders on project. i added them "add files to project" from desktop
can you help me why i take an error ?
cause of wrong import file or
about bundle ?
i don't know objective-c very well so if you give me advice with swift i will be very happy.
thank you
You are missing WKWebView configuration. Please add the following lines before loading your html file to fix the problem.
var theConfiguration = WKWebViewConfiguration()
theWebView = WKWebView(frame:self.view.frame, configuration: theConfiguration)