24

使用 Alamofire.download() 的示例运行良好，但没有详细说明如何访问生成的下载文件。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。

如何访问文件名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？

4

5 回答 5

27

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!)")
    }
)

仍然很难理解为什么他们使用闭包来设置目标路径......

于 2015-11-20T21:56:58.360 回答
13

Alamofire 自述文件上的示例实际上包含文件路径，所以我用一个单独的变量来获取它，以便在我的代码中的其他地方使用。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!)
        }
 }
于 2014-10-16T21:04:35.437 回答
3

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!)
                }
            }
    }
于 2015-06-21T05:49:56.907 回答
2

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)")
            }
    }

}
于 2016-05-26T08:03:06.227 回答
2

来自 Alamofire 成员的这个答案似乎是最好的答案：

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))")
}
于 2016-08-31T14:10:51.627 回答