public async Task <string> RetrieveFileContentsAsync(string fileName, string password, FileLocation location)
{
if (!_initialized)
{
throw new ServiceNotInitializedException($"{nameof(FileService)} was not initialized before access was attempted.");
}
using (await f_lock.Acquire())
{
var collectionToSearch = location == FileLocation.Local ? LocalFiles : RoamedFiles;
var file = collectionToSearch.Single(x => x.Name == fileName);
string encryptedContents = await FileIO.ReadTextAsync(file.BackingFile);
if (String.IsNullOrWhiteSpace(encryptedContents))
{
return(null);
}
string iv = await _ivService.GetValue(GetParentFolder(file.BackingFile), location);
try
{
return(LegacyEncryptionManager.Decrypt(encryptedContents, password, iv));
}
catch (Exception ex)
{
//Just explicitly noting that .Decrypt() can and WILL throw.
throw;
}
}
}
/// <summary>
/// Saves and encrypts the contents into a StorageFile with the given name, and the given password.
/// </summary>
/// <param name="contents">The contents to encrypt.</param>
/// <param name="fileName">The filename with which to save the file.</param>
/// <param name="password">The password that will be used to generate the encryption key.</param>
/// <returns>If successful, returns the created StorageFile.</returns>
public async Task <BindableStorageFile> SaveAndEncryptFileAsync(string contents, string fileName, string password)
{
using (await f_lock.Acquire())
{
if (!_initialized)
{
throw new ServiceNotInitializedException($"{nameof(FileService)} was not initialized before access was attempted.");
}
if (contents == null)
{
throw new ArgumentException("File contents cannot be null.");
}
string iv = Guid.NewGuid().ToString("N"); // OLD IV code.
string encryptedContents = LegacyEncryptionManager.Encrypt(contents, password, iv);
var savedFile = await _localFolder.CreateFileAsync(fileName, CreationCollisionOption.GenerateUniqueName);
await FileIO.WriteTextAsync(savedFile, encryptedContents);
string savedFileName = savedFile.Name;
BindableStorageFile bsf = await BindableStorageFile.Create(savedFile);
LocalFiles.Add(bsf);
await _ivService.Add(GetParentFolder(bsf.BackingFile), iv, FileLocation.Local);
return(bsf);
}
}
