问题
I have successfully Implemented downloading mechanism for pdf files. Files are downloading and save to document directory of simulator. Issue is when I try to disconnect internet the files locally stored not accessible. In my application I have two modes Online and Offline. In Online mode I store data and its accessible at Offline mode. Only problem is getting with pdf files.
How to access pdf files in offline mode?
viewController Code:
let fileType = (URL != nil) ? ".pdf" : ".png"
DataProvider.main.downloadFile(url: String(describing: self.URL!), filetype: fileType, callback: { success, response in
if !success || response == nil {
return false
}
if((response as! String).hasSuffix("pdf")){
self.imageScrollView.isHidden = true
self.contentContainer.isHidden = false
self.document = ReaderDocument(filePath:(response as! String).removingPercentEncoding, password: nil)
self.loadDocument()
self._contentView.removeFromSuperview()
self._contentView.frame = self.contentContainer.bounds
self.contentContainer.addSubview(self._contentView)
}else if (FileManager.default.fileExists(atPath: (response as! String).removingPercentEncoding!) ){
self.imageScrollView.isHidden = false
self.contentContainer.isHidden = true
let image = UIImage(contentsOfFile:(response as! String).removingPercentEncoding!)!
self.imageScrollView.display(image)
}
return true
})
DataProvider Class with custom directory:
@objc public func downloadFile(url:String, filetype: String, callback:@escaping (_ success:Bool, _ result:Any?)->(Bool)) -> Void {
var destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)
if filetype.elementsEqual(".pdf"){
destination = { _, _ in
let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let fileURL = documentsURL.appendingPathComponent(String(abs(url.hashValue)) + ".pdf") //giving different name to file
return (fileURL, [.removePreviousFile, .createIntermediateDirectories])
}
}
Alamofire.download(
url,
method: .get,
parameters: nil,
encoding: JSONEncoding.default,
headers: [ "Accept":"*/*", "Authorization":"Bearer \(token ?? "")"],
to: destination).downloadProgress(closure: { (progress) in
//progress closure
print(progress)
}).response(completionHandler: { (DefaultDownloadResponse) in
//here you able to access the DefaultDownloadResponse
//result closure
callback(DefaultDownloadResponse.response?.statusCode == 200, DefaultDownloadResponse.destinationURL?.absoluteString.replacingOccurrences(of: "file://", with: ""))
print(DefaultDownloadResponse)
})
}
DefaultDownloadResponse.destinationURL when Online downloaded
▿ destinationURL : Optional<URL>
▿ some : file:///Users/macuser/Library/Developer/CoreSimulator/Devices/4B6C2727-46AB-4797-8CBB-D5A897867013/data/Containers/Data/Application/08441079-027E-4A5C-A504-4151A8405CF0/Documents/660444321507407187.pdf
- _url : file:///Users/macuser/Library/Developer/CoreSimulator/Devices/4B6C2727-46AB-4797-8CBB-D5A897867013/data/Containers/Data/Application/08441079-027E-4A5C-A504-4151A8405CF0/Documents/660444321507407187.pdf
when Offline its not downloaded or not picked from local
finished with error [-1009] Error Domain=NSURLErrorDomain Code=-1009 "The Internet connection appears to be offline." UserInfo={_kCFStreamErrorCodeKey=50, NSUnderlyingError=0x600002fd50e0 {Error Domain=kCFErrorDomainCFNetwork Code=-1009 "(null)" UserInfo={_kCFStreamErrorCodeKey=50, _kCFStreamErrorDomainKey=1}}, _NSURLErrorFailingURLSessionTaskErrorKey=LocalDownloadTask <98102CE1-D70F-4A0E-AB89-8CAAEFE29213>.<13>, _NSURLErrorRelatedURLSessionTaskErrorKey=(
"LocalDownloadTask <98102CE1-D70F-4A0E-AB89-8CAAEFE29213>.<13>"
), NSLocalizedDescription=The Internet connection appears to be offline., NSErrorFailingURLStringKey=http://pdfv2.zta.com/Pdf/GetPageFromPdfUrl?url=http://d4static.zed.com/31/2019/8585/6999605/6999605.pdf&page=1,
回答1:
Here I am checking if file exists or not first.
//Call it like this
checkIfFileExists(urlString: "your_url")
func checkIfFileExists(urlString: String) {
let path = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)[0] as String
let url = NSURL(fileURLWithPath: path)
let fileName = urlString.fileName()
let fileManager = FileManager.default
let filePath = url.appendingPathComponent("\(fileName).pdf")?.path
print("filePath : \(String(describing: filePath))")
if fileManager.fileExists(atPath: filePath!) {
print("File exists")
} else {
print("File doesn't exists")
stackoverFlowTask()
}
}
func stackoverFlowTask() {
downloadFile(url: "your_url", filetype: ".pdf", callback: { success, response in
if !success || response == nil {
return false
}
return true
})
}
public func downloadFile(url:String, filetype: String, callback:@escaping (_ success:Bool, _ result:Any?)->(Bool)) -> Void {
var destination = DownloadRequest.suggestedDownloadDestination(for: .documentDirectory)
if filetype.elementsEqual(".pdf"){
destination = { _, _ in
let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
let downloadFileName = url.fileName()
let fileURL = documentsURL.appendingPathComponent("\(downloadFileName).pdf")
return (fileURL, [.removePreviousFile, .createIntermediateDirectories])
}
}
Alamofire.download(
url,
method: .get,
parameters: nil,
encoding: JSONEncoding.default,
headers: nil,
to: destination).downloadProgress(closure: { (progress) in
//progress closure
print(progress)
}).response(completionHandler: { (DefaultDownloadResponse) in
//here you able to access the DefaultDownloadResponse
//result closure
callback(DefaultDownloadResponse.response?.statusCode == 200, DefaultDownloadResponse.destinationURL?.absoluteString.replacingOccurrences(of: "file://", with: ""))
print(DefaultDownloadResponse)
})
}
Extension:
extension String {
func fileName() -> String {
return self.replacingOccurrences(of: "[/+.:.-=.%&]", with: "", options: .regularExpression, range: nil)
}
}
来源：https://stackoverflow.com/questions/59715589/pdf-file-reading-issue-only-on-offline-mode-swift