iOS - 无法从 Parse 后端流式传输视频

Question

最近我创建了自己的解析服务器，托管在 heroku 上，使用 mongoLab 来存储我的数据。

我的问题是我将视频保存为解析 PFFile，但是保存后我似乎无法流式传输它。

这是我的具体步骤。

首先，我保存UIImagePicker返回的视频

//Get the video URL
let videoURL = info[UIImagePickerControllerMediaURL] as? NSURL

//Create PFFile with NSData from URL
let data = NSData(contentsOfURL: videoURL!)
videoFile = PFFile(data: data!, contentType: "video/mp4")

//Save PFFile first, then save the PFUser
PFUser.currentUser()?.setObject(videoFile!, forKey: "profileVideo")
            videoFile?.saveInBackgroundWithBlock({ (succeeded, error) -> Void in
                print("saved video")
                PFUser.currentUser()?.saveInBackgroundWithBlock({ (succeeded, error) -> Void in
                    if succeeded && error == nil {
                        print("user saved")

                        //Hide progress bar 
                        UIView.animateWithDuration(0.5, animations: { () -> Void in                   
                            self.progressBar.alpha = 0
                            }, completion: { (bool) -> Void in
                                self.progressBar.removeFromSuperview()
                        })

                    }else{

                        //Show error if the save failed
                        let message = error!.localizedDescription
                        let alert = UIAlertController(title: "Uploading profile picture error!", message: message, preferredStyle: UIAlertControllerStyle.Alert)
                        let dismiss = UIAlertAction(title: "OK", style: UIAlertActionStyle.Cancel, handler: nil)
                        alert.addAction(dismiss)
                        self.presentViewController(alert, animated: true, completion: nil)

                    }
                })
                }, progressBlock: { (progress) -> Void in
                    self.progressBar.setProgress(Float(progress)/100, animated: true)
            })

这一切都很好。问题出在我检索PFFile 并尝试流式传输视频时。这是我的代码：

//Get URL from my current user
self.videoFile = PFUser.currentUser()?.objectForKey("profileVideo") as? PFFile
                        self.profileVideoURL = NSURL(string: (self.videoFile?.url)!)

//Create AVPlayerController
let playerController = AVPlayerViewController()

//Set AVPlayer URL to where the file is stored on the sever
let avPlayer = AVPlayer(URL: self.profileVideoURL)
playerController.player = avPlayer

//Present the playerController
self.presentViewController(playerController, animated: true, completion: { () -> Void in
 playerController.player?.play()
})

当我展示playerController 时，最终发生的事情是这样的：

为什么在我尝试流式传输视频时会出现这种情况？

非常感谢任何帮助！

更新

我最近尝试使用以下代码行播放从不同数据库保存的视频：let videoURL = NSURL(string: "https://clips.vorwaerts-gmbh.de/big_buck_bunny.mp4")

这确认是我保存 PFFile 的格式导致了错误。

一定是这一行导致错误，因为"video/mp4" 可能不是正确的格式：videoFile = PFFile(data: data!, contentType: "video/mp4")

更新 2

我获取了位于 mongoLab 上的 .mp4 文件的直接链接，发现我可以在 google chrome 中播放它，但不能在 safari 或我的 iPhone 上播放。

更新 3

我发现这是解析 api 本身的问题，与代码无关，因为我的代码在使用原始解析后端（即将关闭的后端）而不是我的自定义解析服务器时运行良好.我目前没有解决方案，但随着时间的推移它应该会得到修复。

Answer 1

对于仍然登陆这里的任何人，在查看新的 Parse-Server-example 更新时，Parse-server 现在可以识别流；但是，您应该使用 Parse iOS sdk 方法来检索视频。如果您要推出自定义解析服务器，则服务器代码如下。接下来是一些流式传输方法的列表。

在以下位置发现服务器代码更改：

parse-server-example\node_modules\parse-server\lib\Routers\FilesRouter

{
key: 'getHandler',
value: function getHandler(req, res) {
  var config = new _Config2.default(req.params.appId);
  var filesController = config.filesController;
  var filename = req.params.filename;
  var contentType = _mime2.default.lookup(filename);
  if (isFileStreamable(req, filesController)) {
    filesController.getFileStream(config, filename).then(function (stream) {
      handleFileStream(stream, req, res, contentType);
    }).catch(function () {
      res.status(404);
      res.set('Content-Type', 'text/plain');
      res.end('File not found.');
    });
  } else {
    filesController.getFileData(config, filename).then(function (data) {
      res.status(200);
      res.set('Content-Type', contentType);
      res.set('Content-Length', data.length);
      res.end(data);
    }).catch(function () {
      res.status(404);
      res.set('Content-Type', 'text/plain');
      res.end('File not found.');
    });
  }
}},

使用iOS parse sdk(swift)进行流式传输的方法示例：

vidObject.video.getDataStreamInBackground(block: <#T##PFDataStreamResultBlock?##PFDataStreamResultBlock?##(InputStream?, Error?) -> Void#>)

Answer 2

我有一个带有解析服务器的本地 mongodb，需要它来使其工作：

Parse-server stream video to IOS from PFFile.url

不知道是否与非本地数据库相同。

Answer 3

parse-server 似乎不支持 Safari/iOS 中的流式传输，解决方案是使用 express 和 GridStore 启用它，如下所示，

parse-server-example\node_modules\parse-server\lib\Routers\FilesRouter

    {
key: 'getHandler',
value: function getHandler(req, res, content) {
var config = new _Config2.default(req.params.appId);
var filesController = config.filesController;
var filename = req.params.filename;
var video = '.mp4'
var lastFourCharacters = video.substr(video.length - 4);
if (lastFourCharacters == '.mp4') {

  filesController.handleVideoStream(req, res, filename).then(function (data) {

    }).catch(function (err) {
      console.log('404FilesRouter');
        res.status(404);
        res.set('Content-Type', 'text/plain');
        res.end('File not found.');
    });
}else{
filesController.getFileData(config, filename).then(function (data) {
  res.status(200);
  res.end(data);
}).catch(function (err) {
    res.status(404);
    res.set('Content-Type', 'text/plain');
    res.end('File not found.');
  });
 }
}
} , ...

parse-server-example\node_modules\parse-server\lib\Controllers\FilesController

_createClass(FilesController, [{
key: 'getFileData',
value: function getFileData(config, filename) {
return this.adapter.getFileData(filename);
}
},{
key: 'handleVideoStream',
value: function handleVideoStream(req, res, filename) {
return this.adapter.handleVideoStream(req, res, filename);
}
}, ...

parse-server-example\node_modules\parse-server\lib\Adapters\Files\GridStoreAdapter

... , {
     key: 'handleVideoStream',
     value: function handleVideoStream(req, res, filename) {
     return this._connect().then(function (database) {
     return _mongodb.GridStore.exist(database, filename).then(function     () {
  var gridStore = new _mongodb.GridStore(database, filename, 'r');
  gridStore.open(function(err, GridFile) {
      if(!GridFile) {
          res.send(404,'Not Found');
          return;
        }
        console.log('filename');
        StreamGridFile(GridFile, req, res);
      });
      });
      })
      }
      }, ...

GridStore 适配器底部

function StreamGridFile(GridFile, req, res) {
var buffer_size = 1024 * 1024;//1024Kb

if (req.get('Range') != null) { //was: if(req.headers['range'])
  // Range request, partialle stream the file
  console.log('Range Request');
  var parts = req.get('Range').replace(/bytes=/, "").split("-");
  var partialstart = parts[0];
  var partialend = parts[1];
  var start = partialstart ? parseInt(partialstart, 10) : 0;
  var end = partialend ? parseInt(partialend, 10) : GridFile.length - 1;
  var chunksize = (end - start) + 1;

  if(chunksize == 1){
    start = 0;
    partialend = false;
  }

  if(!partialend){
    if(((GridFile.length-1) - start) < (buffer_size) ){
        end = GridFile.length - 1;
    }else{
      end = start + (buffer_size);
    }
      chunksize = (end - start) + 1;
    }

    if(start == 0 && end == 2){
      chunksize = 1;
    }

res.writeHead(206, {
      'Cache-Control': 'no-cache',
    'Content-Range': 'bytes ' + start + '-' + end + '/' + GridFile.length,
    'Accept-Ranges': 'bytes',
    'Content-Length': chunksize,
    'Content-Type': 'video/mp4',
  });

  GridFile.seek(start, function () {
    // get GridFile stream

            var stream = GridFile.stream(true);
            var ended = false;
            var bufferIdx = 0;
            var bufferAvail = 0;
            var range = (end - start) + 1;
            var totalbyteswanted = (end - start) + 1;
            var totalbyteswritten = 0;
            // write to response
            stream.on('data', function (buff) {
            bufferAvail += buff.length;
            //Ok check if we have enough to cover our range
            if(bufferAvail < range) {
            //Not enough bytes to satisfy our full range
                if(bufferAvail > 0)
                {
                //Write full buffer
                  res.write(buff);
                  totalbyteswritten += buff.length;
                  range -= buff.length;
                  bufferIdx += buff.length;
                  bufferAvail -= buff.length;
                }
            }
            else{

            //Enough bytes to satisfy our full range!
                if(bufferAvail > 0) {
                  var buffer = buff.slice(0,range);
                  res.write(buffer);
                  totalbyteswritten += buffer.length;
                  bufferIdx += range;
                  bufferAvail -= range;
                }
            }

            if(totalbyteswritten >= totalbyteswanted) {
            //  totalbytes = 0;
              GridFile.close();
              res.end();
              this.destroy();
            }
            });
        });

  }else{

//  res.end(GridFile);
        // stream back whole file
      res.header('Cache-Control', 'no-cache');
      res.header('Connection', 'keep-alive');
      res.header("Accept-Ranges", "bytes");
      res.header('Content-Type', 'video/mp4');
      res.header('Content-Length', GridFile.length);
      var stream = GridFile.stream(true).pipe(res);
   }
  };

附言 @Bragegs 在这里给出了原始答案 - https://github.com/ParsePlatform/parse-server/issues/1440#issuecomment-212815625 。用户@Stav1 在这个帖子中也提到了它，但不幸的是他被否决了？

Answer 4

这段代码对我有用

let playerController = AVPlayerViewController()

      self.addChildViewController(playerController)
      self.view.addSubview(playerController.view)
      playerController.view.frame = self.view.frame

      file!.getDataInBackgroundWithBlock({
        (movieData: NSData?, error: NSError?) -> Void in
        if (error == nil) {

          let filemanager = NSFileManager.defaultManager()

          let documentsPath : AnyObject = NSSearchPathForDirectoriesInDomains(.DocumentDirectory,.UserDomainMask,true)[0]
          let destinationPath:NSString = documentsPath.stringByAppendingString("/file.mov")
          movieData!.writeToFile ( destinationPath as String, atomically:true)


          let playerItem = AVPlayerItem(asset: AVAsset(URL: NSURL(fileURLWithPath: destinationPath as String)))
          let player = AVPlayer(playerItem: playerItem)
          playerController.player = player
          player.play()
        } else {
          print ("error on getting movie data \(error?.localizedDescription)")
        }
      })