DownloadFile Method

Downloads a file.

Syntax

int DownloadFile(const QString& qsFilePath);

Remarks

This method downloads the file at the specified FilePath in the share currently selected by Share.

If LocalFile is set, the file will be saved to the specified location; otherwise, the file data will be held by ResourceData.

To download and decrypt an encrypted file, set EncryptionAlgorithm and EncryptionPassword before calling this method.

Download Notes

In the simplest use-case, downloading a file looks like this:

azurefile.LocalFile = "../MyFile.zip";
azurefile.DownloadFile(azurefile.Resources[0].Path);

Resuming Downloads

The class also supports resuming failed downloads by using the StartByte property. If a download is interrupted, set StartByte to the appropriate offset before calling this method to resume the download.

string downloadFile = "../MyFile.zip";
azurefile.LocalFile = downloadFile;
azurefile.DownloadFile(azurefile.Resources[0].Path);

//The transfer is interrupted and DownloadFile() above fails. Later, resume the download:

//Get the size of the partially downloaded file
azurefile.StartByte = new FileInfo(downloadFile).Length;
azurefile.DownloadFile(azurefile.Resources[0].Path);

Resuming Encrypted File Downloads

Resuming encrypted file downloads is only supported when LocalFile was set in the initial download attempt.

If LocalFile is set when beginning an encrypted download, the class creates a temporary file in TempPath to hold the encrypted data until the download is complete. If the download is interrupted, DownloadTempFile will be populated with the path of the temporary file that holds the partial data.

To resume, DownloadTempFile must be populated, along with StartByte, to allow the remainder of the encrypted data to be downloaded. Once the encrypted data is downloaded it will be decrypted and written to LocalFile.

azurefile.LocalFile = "../MyFile.zip";
azurefile.EncryptionPassword = "password";
azurefile.DownloadFile(azurefile.Resources[0].Path);

//The transfer is interrupted and DownloadFile() above fails. Later, resume the download:

//Get the size of the partially download temp file
azurefile.StartByte = new FileInfo(azurefile.Config("DownloadTempFile")).Length;
azurefile.DownloadFile(azurefile.Resources[0].Path);

Error Handling

This method returns a result code; 0 indicates success, while a non-zero error code indicates that this method encountered an error during its execution. If an error occurs, the GetLastError() method can be called to retrieve the associated error message. (Note: This method's result code can also be obtained by calling the GetLastErrorCode() method after it returns.)