vb.net – Google Drive V3 Resumable Download

2023年7月13日 270次阅读

我使用此代码使用Google Drive api V3从Google云端硬盘下载文件：

    Function gDownload() As Boolean

            Dim fileID As String = "0B-W1aRTTOB1QM3hPd0dOUFVObHM"
            Dim stream = New System.IO.MemoryStream()        
            Dim r = service.Files.Get(fileID)
            Dim m = r.MediaDownloader
            m.ChunkSize = 256 * 1024
            AddHandler m.ProgressChanged, AddressOf Download_ProgressChanged    
    mStart:    
            r.Download(stream)    
            Return True ' or False if download failed

    End Function

   Private Sub Download_ProgressChanged(s As IDownloadProgress)
            Console.WriteLine(s.Status.ToString & "   " & s.BytesDownloaded)
   End Sub

这可以很好地与稳定连接,但如果我失去连接它会停止并等待永远,即使我再次重新连接.

我在这段代码中没有更新(上传)功能的问题：

Function gUpload() As Boolean

        Dim fileID As String = "0B-W1aRTTOB1QM3hPd0dOUFVObHM"
        Dim stream As New System.IO.FileStream("D:\gtest\Test.mp4", System.IO.FileMode.Open)
        Dim fBody As File = New File With {.Name = "Test.mp4"}

        Dim r = service.Files.Update(fBody, fileID, stream, "application/octet-stream")
        r.ChunkSize = ResumableUpload.MinimumChunkSize
        AddHandler r.ProgressChanged, AddressOf Upload_ProgressChanged

  mStart:
        r.Resume()
        If r.GetProgress.Status = 3 Then ' UploadStatus.Completed
            Return True
        Else
            If MessageBox.Show("Failed. do you want to resume?", "Failed", MessageBoxButtons.YesNo) = DialogResult.Yes Then
                GoTo mStart
            End If
        End If
        Return False
End Function    

Private Sub Upload_ProgressChanged(s As IUploadProgress)
    Console.WriteLine(s.Status.ToString & "   " & s.BytesSent)
End Sub

这完全符合我的要求,如果我失去连接一段时间(15~30s),它会发出上传失败的消息,并让用户可以选择恢复或退出.一切都很完美.

所以我的问题是：如何让下载功能像上传功能一样工作,或者至少使它不会永远等待,并给出一个失败的消息.

最佳答案 我有同样的问题,我暂时解决了“同时”

    Request.DownloadAsync(Stream)

    Dim bytes_downloaded As Long = 0
    Dim not_downloaded As Integer = 0
    Dim progress As Integer = Stream.Length
    Do While progress < file_size
        progress = Stream.Length

        If progress = bytes_downloaded Then
            not_downloaded += 1
            If not_downloaded >= 900 Then '90 seconds
                ' msg download falhou
                Exit Do
            End If
        Else
            not_downloaded = 0
        End If
        bytes_downloaded = progress
        Threading.Thread.Sleep(100)
    Loop
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