Whilst implementing several HTTP calls, I noticed some strange behaviour on the URLSession. As far as I know, URLSession data tasks used to immediately throw an error when the network connection was unavailable (error -1009 The Internet connection appears to be offline).
I'm now performing network requests too, and while executing a request in flight mode, the request runs for as long as the timeout, before failing. I tried creating a custom configuration that should prevent this, but this does not work. How can I re-enable or configure the behaviour where a request will immediately crash when there is no connection?
let url = URL(string: "https://www.google.com/")!
let config = URLSessionConfiguration.default
config.waitsForConnectivity = false
config.timeoutIntervalForRequest = 2
config.timeoutIntervalForResource = 0
URLSession(configuration: config).dataTask(with: url) { d, r, e in
print(d?.count, (r as? HTTPURLResponse)?.statusCode, e?.localizedDescription)
}.resume()
The configuration documentation appears to be inconsistent or incorrect.
Related
I am getting numerous failed requests with Alamofire 5.3, where the response object itself is nil, or the error is "cannot parse response". I can see from the server logs that all of those requests are returning valid.
Here is my setup:
API manager class:
let config = Alamofire.Session.default.session.configuration
self.session = Alamofire.Session(configuration: config, interceptor: AccessTokenInterceptor())
AccessTokenInterceptor:
class AccessTokenInterceptor: RequestInterceptor {
func adapt(_ urlRequest: URLRequest, for session: Alamofire.Session, completion: #escaping (AdapterResult<URLRequest>) -> Void) {
var adaptedRequest = urlRequest
adaptedRequest.setValue("application/json", forHTTPHeaderField: "Accept")
adaptedRequest.setValue("application/json", forHTTPHeaderField: "Content-Type")
if let token = SettingsManager.shared.userToken {
adaptedRequest.setValue("Bearer " + token, forHTTPHeaderField: "Authorization")
}
completion(.success(adaptedRequest))
}
}
This interceptor inserts my auth token from SettingsManager
I am also using the standard router for URLRequestConvertible where encoding is done by JSON serialization (dictionary) or Codable protocol (objects)
case .login(let body):
request.httpBody = try JSONSerialization.data(withJSONObject: body, options: [])
case .register(let object):
request.httpBody = try JSONEncoder().encode(object)
What is strange is that I don't think I'm doing anything different from the many other times I've used Alamofire and now the first request I make fails but the following one succeeds. If I remove the interceptor, there is no change.
If I inspect the outgoing headers or body content, it all seems normal, but the response from Alamofire is nil.
UPDATE: By using OS_ACTIVITY_MODE and iOS 13 I was able to see that it was complaining about the request headers and protocol. The server is on Elastic Beanstalk so I've been trying to mess with the SSL policy but still the first request fails every time.
This turned into quite the rabbit hole, so in the interest of community improvement, here is what I found.
After searching through the activity log errors, I noticed that iOS was complaining about an invalid header type -- upgrade. Searching for that value I found this question about removing the header. I learned that Apache acts as a proxy on Elastic Beanstalk but there is a mix up for HTTP/2 headers in the request, and iOS does not like that.
To get away from the header value, I ended up switching to Nginx proxy. Since my application uses Laravel, I then needed to deal with correcting the pretty URLs. To do that I found this answer. Now my web and mobile application both seem to be getting along nicely.
I want to set different timeouts for different requests. My request routine looks like:
var request = URLRequest(url: url,
cachePolicy: .reloadIgnoringLocalCacheData,
timeoutInterval: timeout)
// setting headers and body...
sessionTask = localURLSession.dataTask(with: request)
sessionTask?.resume()
where localURLSession is defined as public var:
public var localURLSession: Foundation.URLSession {
return Foundation.URLSession(configuration: localConfig, delegate: self, delegateQueue: nil)
}
public var localConfig: URLSessionConfiguration {
let res = URLSessionConfiguration.default
res.timeoutIntervalForRequest = Self.ordinaryRequestsTimeout // 20 seconds
return res
}
Then I have 2 problems:
When I make 2 simultaneous requests with 100% loss Network Link
Conditioner (first with 20 seconds timeout and second – with 40
seconds), both requests fails after 8 seconds. I don't understand
why.
When I make one request for the first time with 100% loss
Network Link Conditioner, it fails in timeout like expected, but
retrying this request fails in 1 second. I want to wait all the
timeout every time.
In all likelihood, for the 8-second failure, the DNS request is timing out, so you aren't connecting at all.
For the 1-second failure, the OS has probably concluded that the host is unreachable, and won't even try again until the network changes or it successfully makes at least one request to some host somewhere (negative DNS caching).
That said, without a packet trace, I can't be certain of either of those statements.
I have an app running on a test server that doesn't support https. I added the ATS exceptions in the info.plist and it worked well on the devices I tested on.
Now some of my test flight users started complaining about the app not being able to connect to the server. One of the devices in my office started having this problem too, so I had the change to look into it.
I am making a server request like this:
let path = "http://myurl.com"
let request = NSMutableURLRequest(URL: NSURL(string: path)!)
let configuration = NSURLSessionConfiguration.defaultSessionConfiguration()
let session = NSURLSession(configuration: configuration, delegate: self, delegateQueue: NSOperationQueue.mainQueue())
let task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
let httpResponse = response as? NSHTTPURLResponse
print(httpResponse)
print(NSString.init(data: data!, encoding: NSUTF8StringEncoding)!)
})
task.resume()
Now when I look at the URL from the NSHTTPURLResponse it is printed as "https://myurl.com". Somehow it just added the 's' to it. This only happens on some devices, I can't seem to find a pattern.
When I open the https url in a browser I get redirected to some other project we're working on. When I look at the response data that's exactly what I see. So somehow on some devices when you enter a http url it just converts it to https or something...
So far it's only been on iOS9 devices, but that may very well be a coincidence. Does anyone have an idea why this happens and what to do about it?
I'm creating an IOS app using swift.
Recently, I've encountered a weird bug.
Im trying to check if a url is valid, therefore, I'm creating a request with the url and check for the response. I do this task with dataTaskWithRequest of NSUrlSession.
The weird bug is that if the URL is alibaba ,the response returns after a long time(more than 20 seconds sometimes).
Why does that happen?
As far as i concerned it happens only with this specific url.
Here is some code although its not necessary .
let request = NSMutableURLRequest(URL: validatedUrl)
request.HTTPMethod = "HEAD"
let session = NSURLSession.sharedSession()
let task = session.dataTaskWithRequest(request){ data, response, error in
// The response here returns after a very long time
let url = request.URL!.absoluteString
I would appreciate some help guys!
You're retrieving the contents of a URL over the Internet. The speed at which this happens is arbitrary. It depends on the speed of the DNS server that looks up the hostname, the speed of the web server that responds to the request, the speed of the user's Internet connection, and the speed of every network in between.
You can safely assume that it will either succeed or time out within three minutes. Twenty seconds isn't even slightly unusual over a cellular network.
You should probably rethink what you're doing with this URL and why you're doing it, or at least try to figure out a way to avoid keeping the user waiting while you fetch the URL.
I am developing an iOS app which required to connect with web socket server.
I can successfully connect to server but when I send request on it, it drop off the connection.
I am using Starscream library for web socket.
As per server support team:
it does not support protocol compression, but in the headers below they're requesting "permessage-deflate" from us. We'll accept uncompressed messages just fine (it's just a flag on the packet) but due to the extension they asked for, messages we send out will be compressed with that flag set.
I send request as following using Swift
let dict = ["Parameter1":"value1","Parameter2":"value2"]
do {
let data = try NSJSONSerialization.dataWithJSONObject(dict, options: NSJSONWritingOptions(rawValue: 0))
var jsonString: String = String(data: data, encoding: UInt())!
self.socket.writeString(jsonString);
} catch {
print(error)
}
It disconnect with server and print following message.
"websocket is disconnected: Optional("masked and rsv data is not currently supported")"
What the server support team meant is that the request from your WebSocket client application contained an HTTP header like below.
Sec-WebSocket-Extensions: permessage-deflate
So, if your application has a line like below, remove it.
socket.headers["Sec-WebSocket-Extensions"] = "permessage-deflate"
This error might also be thrown if the server doesn't accept the incoming connection (regardless of the reasons), or if the server crashed.
Basically, when this message shows up, the best action would be to check what is going on the server as you might be wasting time trying improve client code (it happened to me :)
For those facing this issue when trying to connect to the backend WebSocket, make sure the front end and the backend version of the socket.io are compatible. Running the following command fixed the issue for me.
pod update
Updated the both to the latest and solved the issue.
this will fix your issue I believe. just add "wamp" in the header like this.
*
var request = URLRequest(url: URL(string: URL)!)
request.setValue(["wamp"].joined(separator: ","), forHTTPHeaderField: "Sec-WebSocket-Protocol")
socket = WebSocket(request: request)
socket.delegate = self
socket.connect()