NSURLSession使用绑定流上传后台文件 [英] NSURLSession Background File Upload using Bound Streams

问题描述

我正在研究一个我们需要支持的项目：

• 使用 NSURLSession 来上传文件。


• 服务器需要使用 Content-Type：multipart / form-data


• 以前，我使用 NSURLConnection 和绑定的Stream对，如 Apple示例。


• 现在，我希望通过使用 uploadTaskWithStreamedRequest ：。

，使用 NSURLSession（后台会话）
• 我已经编写了一个独立的iOS Sample +一个PHP服务器来验证我的概念。
  

问题： 一切工作，如果应用程序停留在前台，但如果在上传期间，我按Home键，一段时间后上传失败，错误：

Domain = NSURLErrorDomain Code = -997与后台传输服务器失去连接ice

在上传失败之前，写/生成器流的 NSStreamEventEndEncountered 遇到。

注意：我知道解决方法，我可以将整个HTTP Post主体写入临时文件并使用 NSURLSession的文件上传API。但是，如果我可以做到这一点，以上是更合适的。

问题：有人可以猜测上传失败的可能原因是什么？

示例代码：我上传了iOS示例代码+ PHP服务器代码。这里是代码

谢谢！

解决方案

您无法使用后台配置上传流式传输任务。我只在两种情况下成功上传数据：
$ b $ ol

使用存储在请求正文中的数据下载任务

从文件上传任务。在这种情况下，您将不会收到回复正文。

History:

I am working on a project for which we need to support:

• Background Upload of files using NSURLSession.
• The server expects file to be uploaded using Content-Type: multipart/form-data
• Previously, I was using NSURLConnection with bound pair of Streams as depicted in this Apple Sample.
• Now, I wish to follow similar approach with NSURLSession(Background Session) by using uploadTaskWithStreamedRequest:.
• I have written a small stand-alone iOS Sample + a PHP server to validate my concept.

Problem: Everything works if app stays in foreground, but if during upload I press the home key, the upload fails after some time with error:

Domain=NSURLErrorDomain Code=-997 "Lost connection to background transfer service"

Also a little before the upload fails the Write/Producer Stream's NSStreamEventEndEncountered is encountered.

Note: I know the work-around where I can write whole HTTP Post body to a temp file and use NSURLSession's file upload API instead. But above is more appropriate if I can make it work.

Question: Can anyone guess what could be possible reason for the upload getting failed?

Sample Code: I have uploaded the iOS Sample Code + PHP Server Code to drop box. Here is the CODE

Thanks!

解决方案

You can't upload streamed tasks using Background Configuration. I successfully upload data only in two cases:

1. Download task with data stored in request body.
2. Upload task from file. In that case you will not receive response body.

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