[英]Alamofire progress callback stops working after returning from background
我有一種將(視頻)數據上傳到服務器的方法,它看起來像這樣:
static func upload(video data:Data, named name:String, parameters:[String:Any], toUrl url:URL, progress:@escaping (Double)->Void, completion:@escaping(Bool)->Void){
manager = Alamofire.SessionManager(configuration: URLSessionConfiguration.background("com.app.backgroundtransfer")
manager.upload(multipartFormData: { (multipartFormData) in
multipartFormData.append(data, withName: "filedata", fileName: name, mimeType: "video/quicktime")
for key in parameters.keys{
if let val = parameters[key] as? String{
multipartFormData.append(val.data(using: .utf8, allowLossyConversion: false)!, withName: key)
}
}
}, to: url) {
(encodingResult) in
switch encodingResult {
case .success(let upload, _, _):
upload.uploadProgress(closure: { (uploadProgress) in
progress(uploadProgress.fractionCompleted)
//this one stops getting called
})
upload.responseJSON { response in
// but this one gets called at the end.
}
case .failure(let encodingError):
print(encodingError)
}
}
}
所以問題是,從后台返回時(在上傳過程中),我無法正確更新UI。
為什么此進度回調停止工作(從后台返回后)?
Alamofire與后台會話並不完全兼容。 由於這是一個基於閉包的API,當應用程序進入后台時無法持久保存,因此當應用程序前台運行時,不會關閉您的進度閉包。 我們建議您直接使用URLSession
或使用后台任務API代替后台會話。
因此,我所做的是使用后台任務(在沒有Alamofire的情況下也完全完成了此任務)並且有效。 像這樣:
var backgroundTask: UIBackgroundTaskIdentifier = .invalid
func registerBackgroundTask() {
backgroundTask = UIApplication.shared.beginBackgroundTask {
self.endBackgroundTask()
}
assert(backgroundTask != .invalid)
}
func endBackgroundTask() {
print("Background task ended.")
UIApplication.shared.endBackgroundTask(backgroundTask)
backgroundTask = .invalid
}
APIClient.manager = Alamofire.SessionManager(configuration: URLSessionConfiguration.background(withIdentifier: "com.app.backgroundtransfer"))
self.registerBackgroundTask()
APIClient.upload(video: video, named: videoDetailsModel.videoURL!.lastPathComponent, parameters: self.uploadParameters, toUrl: url, progress: {[weak self] (percentage) in
guard let `self` = self else {return}
print("Progress \(percentage)")
self.progressBar.progress = CGFloat(percentage)
}, completion: { [weak self] (success) in
guard let `self` = self else {return}
if(success){
print("Video successfully uploaded")
self.endBackgroundTask()
self.progressBar.progress = 1.0
}else{
print("Video upload was not successfull")
}
})
現在進度回調正常工作,您仍然可以使用Alamofire打包多部分數據,就像我正在使用它一樣,或者出於任何原因使用它。
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