使用 Alamofire.download() 的示例运行良好，但没有任何关于如何访问生成的下载文件的详细信息。我可以根据我设置的目标和我提出的原始文件请求找出文件的位置和名称，但我会假设我应该能够访问一个值以获得完整的最终下载路径和响应中的文件名。
我如何访问文件的名称以及如何知道它是否保存成功？我可以在实际的 Alamofire 代码中看到似乎处理下载过程的委托完成调用的委托方法，但是我/我如何访问 .response 块中的文件详细信息？
【问题讨论】：
标签： alamofire
Swift 2.1 和更简单一点：
var localPath: NSURL?
Alamofire.download(.GET,
"http://jplayer.org/video/m4v/Big_Buck_Bunny_Trailer.m4v",
destination: { (temporaryURL, response) in
let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
let pathComponent = response.suggestedFilename
localPath = directoryURL.URLByAppendingPathComponent(pathComponent!)
return localPath!
})
.response { (request, response, _, error) in
print(response)
print("Downloaded file to \(localPath!)")
}
)
仍然很难理解他们为什么要使用闭包来设置目标路径...
【讨论】：
Alamofire 自述文件中的示例实际上包含文件路径，因此我使用单独的变量来获取它，以便在代码的其他地方使用。它不是很优雅，我希望有一种方法可以在响应中获取该信息，但现在，这是完成工作：
var fileName: String?
var finalPath: NSURL?
Alamofire.download(.GET, urlToCall, { (temporaryURL, response) in
if let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as? NSURL {
fileName = response.suggestedFilename!
finalPath = directoryURL.URLByAppendingPathComponent(fileName!)
return finalPath!
}
return temporaryURL
})
.response { (request, response, data, error) in
if error != nil {
println("REQUEST: \(request)")
println("RESPONSE: \(response)")
}
if finalPath != nil {
doSomethingWithTheFile(finalPath!, fileName: fileName!)
}
}
【讨论】：
我花了大约 8 个小时来寻找这个问题的答案。下面的解决方案对我有用，基本上我链接到下载方法来显示图像。在下面的示例中，我正在下载知道其 Facebook ID 的用户的个人资料图片：
let imageURL = "http://graph.facebook.com/\(FBId!)/picture?type=large"
let destination: (NSURL, NSHTTPURLResponse) -> (NSURL) = {
(temporaryURL, response) in
if let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as? NSURL {
var localImageURL = directoryURL.URLByAppendingPathComponent("\(self.FBId!).\(response.suggestedFilename!)")
return localImageURL
}
return temporaryURL
}
Alamofire.download(.GET, imageURL, destination).response(){
(_, _, data, _) in
if let directoryURL = NSFileManager.defaultManager().URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0] as? NSURL {
var error: NSError?
let urls = NSFileManager.defaultManager().contentsOfDirectoryAtURL(directoryURL, includingPropertiesForKeys: nil, options: nil, error: &error)
if error == nil {
let downloadedPhotoURLs = urls as! [NSURL]
let imagePath = downloadedPhotoURLs[0] // assuming it's the first file
let data = NSData(contentsOfURL: imagePath)
self.viewProfileImage?.image = UIImage(data: data!)
}
}
}
【讨论】：
这是在不同目的地下载文件的完整方法
//MARK：下载方法
func downloadFile(reqType : RequestType, urlParam: String,completionHandler: (Double?, NSError?) -> Void) {
let documentsPath = NSURL(fileURLWithPath: NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0])
var downloadPath = documentsPath.URLByAppendingPathComponent("downloads")
var isDirectory: ObjCBool = false
if NSFileManager.defaultManager().fileExistsAtPath(downloadPath.path!, isDirectory: &isDirectory) {
if(!isDirectory){
do {
try NSFileManager.defaultManager().createDirectoryAtPath(downloadPath.path!, withIntermediateDirectories: true, attributes: nil)
}catch {
NSLog("Unable to create directory ")
}
}
}else{
do {
try NSFileManager.defaultManager().createDirectoryAtPath(downloadPath.path!, withIntermediateDirectories: true, attributes: nil)
}catch {
NSLog("Unable to create directory ")
}
}
//get the url from GTM
let urlString = self.getRequestedUrlFromIdentifier(reqType, param: urlParam)
let destination = Alamofire.Request.suggestedDownloadDestination(directory: .DocumentDirectory, domain: .UserDomainMask)
Alamofire.download(.GET, urlString, destination: { (temporaryURL, response) in
let pathComponent = response.suggestedFilename
downloadPath = downloadPath.URLByAppendingPathComponent(pathComponent!)
if NSFileManager.defaultManager().fileExistsAtPath(downloadPath.path!) {
do{
try NSFileManager.defaultManager().removeItemAtPath(downloadPath.path!)
}catch {
}
}
return downloadPath
}) .progress { bytesRead, totalBytesRead, totalBytesExpectedToRead in
print(totalBytesRead)
// This closure is NOT called on the main queue for performance
// reasons. To update your ui, dispatch to the main queue.
dispatch_async(dispatch_get_main_queue()) {
print("Total bytes read on main queue: \(totalBytesRead)")
}
}
.response { request, response, _, error in
print(response)
let originalPath = destination(NSURL(string: "")!, response!)
if let error = error {
completionHandler(500000.1 , nil)
print("Failed with error: \(error)")
} else {
completionHandler(500000.0 , nil)
print("Downloaded file successfully \(downloadPath)")
}
}
}
【讨论】：
来自 Alamofire 成员的This answer 似乎是最佳答案：
let destination = Alamofire.Request.suggestedDownloadDestination(
directory: .CachesDirectory,
domain: .UserDomainMask
)
Alamofire.download(.GET, "http://www.adobe.com/devnet/acrobat/pdfs/pdf_open_parameters.pdf", destination: destination)
.progress { bytesRead, totalBytesRead, totalBytesExpectedToRead in
print(totalBytesRead)
}
.response { request, response, _, error in
print(response)
print("fileURL: \(destination(NSURL(string: "")!, response))")
}
【讨论】：