在 Swift 3.0 中设置 Alamofire 自定义目标文件名而不是使用建议的DownloadDestination

Posted 2023-02-24

【中文标题】在 Swift 3.0 中设置 Alamofire 自定义目标文件名而不是使用建议的DownloadDestination

【英文标题】：Setting Alamofire custom destination file name instead of using suggestedDownloadDestination in Swift 3.0

【发布时间】：2016-12-14 06:57:52

【问题描述】：

如何在 swift 3.0 中编写以下 sn-p ？以下语法在swift 2中

    Alamofire.download(.POST, invoice.url,parameters:params, destination:  (url, response) -> NSURL in

        let pathComponent = response.suggestedFilename

        let fileManager = NSFileManager.defaultManager()
        let directoryURL = fileManager.URLsForDirectory(.DocumentDirectory, inDomains: .UserDomainMask)[0]
        let fileUrl = directoryURL.URLByAppendingPathComponent(pathComponent)
        return fileUrl
    )
    .progress  bytesRead, totalBytesRead, totalBytesExpectedToRead in
        print(totalBytesRead)
        dispatch_async(dispatch_get_main_queue()) 
            let progress = Double(totalBytesRead) / Double(totalBytesExpectedToRead)
            completionHandler(progress, nil)
        
    
    .responseString  response in
        print(response.result.error)
        completionHandler(nil, response.result.error)
    

【问题讨论】：

获取响应 mime 类型并添加正确的文件扩展名

Alamofire 版本是最新的 4.2.0 和 swift 3.0

【参考方案1】：

在 Swift 3 中是这样的。

let parameters: Parameters = ["foo": "bar"]

let destination: DownloadRequest.DownloadFileDestination =  _, _ in
    let pathComponent = "yourfileName"
    let documentsURL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
    let fileURL = documentsURL.appendPathComponent(pathComponent)
    return (fileURL, [.removePreviousFile, .createIntermediateDirectories])


Alamofire.download(urlString, method: .get, parameters: parameters, encoding: JSONEncoding.default, to: destination)
    .downloadProgress(queue: DispatchQueue.global(qos: .utility))  progress in
        print("Progress: \(progress.fractionCompleted)")
    
    .validate  request, response, temporaryURL, destinationURL in
        // Custom evaluation closure now includes file URLs (allows you to parse out error messages if necessary)
        return .success
    
    .responseJSON  response in
        debugPrint(response)
        print(response.temporaryURL)
        print(response.destinationURL)
    

查看Alamofire Documentation 或Alamofire 4.0 Migration Guide 了解更多详情。

【讨论】：

在我上面的代码中，它的 let pathComponent = response.suggestedFilename。这个怎么写？

@ZubinGala 我没试过，但是，改变这样的东西，在DownloadRequest.DownloadFileDestination 用响应替换第二个_，然后使用let pathComponent = response.suggestedFilename

@ZubinGala 欢迎朋友 :)

【参考方案2】：

使用func appendingPathComponent(_ pathComponent: String) -> URL 代替appendPathComponent。

let destination: DownloadRequest.DownloadFileDestination =  _, _ in
    let pathComponent = "yourfileName"
    let directoryURL: URL = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
    let folderPath: URL = directoryURL.appendingPathComponent("Downloads", isDirectory: true)
    let fileURL: URL = folderPath.appendingPathComponent(pathComponent)
    return (fileURL, [.removePreviousFile, .createIntermediateDirectories])

也可以使用response。

let destination: DownloadRequest.DownloadFileDestination =  _, response in
    let pathComponent = response.suggestedFilename!
    let directoryURL: URL = FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask)[0]
    let folderPath: URL = directoryURL.appendingPathComponent("Downloads", isDirectory: true)
    let fileURL: URL = folderPath.appendingPathComponent(pathComponent)
    return (fileURL, [.removePreviousFile, .createIntermediateDirectories])