Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost - ios

Question

I am getting this error when using SwiftyBeaver logger, which tries to send data to the cloud via this code:
func sendToServerAsync(str: String?, complete: (ok: Bool, status: Int) -> ()) {
if let payload = str, let queue = self.queue {
// create operation queue which uses current serial queue of destination
let operationQueue = NSOperationQueue()
operationQueue.underlyingQueue = queue
let session = NSURLSession(configuration:
NSURLSessionConfiguration.defaultSessionConfiguration(),
delegate: nil, delegateQueue: operationQueue)
// assemble request
let request = NSMutableURLRequest(URL: serverURL)
request.HTTPMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
// basic auth header
let credentials = "\(appID):\(appSecret)".dataUsingEncoding(NSUTF8StringEncoding)!
let base64Credentials = credentials.base64EncodedStringWithOptions([])
request.setValue("Basic \(base64Credentials)", forHTTPHeaderField: "Authorization")
// POST parameters
let params = ["payload": payload]
do {
request.HTTPBody = try NSJSONSerialization.dataWithJSONObject(params, options: [])
} catch let error as NSError {
toNSLog("Error! Could not create JSON for server payload. \(error)")
}
//toNSLog("sending params: \(params)")
//toNSLog("\n\nbefore sendToServer on thread '\(threadName())'")
sendingInProgress = true
// send request async to server on destination queue
let task = session.dataTaskWithRequest(request) {
_, response, error in
var ok = false
var status = 0
//toNSLog("callback of sendToServer on thread '\(self.threadName())'")
if let error = error {
// an error did occur
self.toNSLog("Error! Could not send entries to server. \(error)")
} else {
if let response = response as? NSHTTPURLResponse {
status = response.statusCode
if status == 200 {
// all went well, entries were uploaded to server
ok = true
} else {
// status code was not 200
var msg = "Error! Sending entries to server failed "
msg += "with status code \(status)"
self.toNSLog(msg)
}
}
}
return complete(ok: ok, status: status)
}
task.resume()
}
}
The strange thing is it works for the first two or three log entries, and then stops due to the above error. I tried to reset content and settings on the simulator and reboot my simulator (as suggested in Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost.") but that just fixes it temporarily--after the first 2-3 log entries, it starts failing again.
I tried debugging this for hours with the creator of SwiftBeaver last night, but we couldn't get it to work. Seems like not many people are seeing this issue.
I tried removing my Wifi connection and reconnecting, but that didn't work either.
Any guidance on this would be much appreciated.
FYI, I'm using Swift 2 and XCode 7.3.

Answer 1

This is probably caused by HTTP keep-alive support being seriously buggy in the iOS simulator. See:
Error Domain=NSURLErrorDomain Code=-1005 "The network connection was lost."
for more details, but the short answer is to disable keep-alive on the server that you use when doing simulator testing, or better yet, add some logic that immediately retries the request if it sees that particular error.