public static async Task MetadataApi_GetDownloadUriAsync_Returns_File_Download_Uri_Which_Downloads_Correct_File()
{
// Arrange
MetadataApi target = CreateAuthorizedService();
List <PackageGroup> packages = await target.GetAvailablePackagesAsync();
DataFile dataFile = packages
.SelectMany((p) => p.Packages)
.First()
.Files
.First();
// Act
Uri result = await target.GetDownloadUriAsync(dataFile.FileName, dataFile.MD5Hash);
// Assert
Assert.NotNull(result);
Assert.True(result.IsAbsoluteUri);
string tempPath = Path.Combine(Path.GetTempPath(), dataFile.FileName);
try
{
using (HttpClient client = new HttpClient())
{
using (var request = new HttpRequestMessage(HttpMethod.Get, result))
{
using (
Stream contentStream = await(await client.SendAsync(request)).Content.ReadAsStreamAsync(),
stream = new FileStream(tempPath, FileMode.Create, FileAccess.Write, FileShare.None, 4096, true))
{
await contentStream.CopyToAsync(stream);
}
}
}
Assert.True(File.Exists(tempPath));
byte[] hash;
using (Stream stream = File.OpenRead(tempPath))
{
Assert.Equal(dataFile.Size, stream.Length);
using (HashAlgorithm algorithm = MD5.Create())
{
hash = algorithm.ComputeHash(stream);
}
}
string hashString = string.Concat(hash.Select((p) => p.ToString("x2", CultureInfo.InvariantCulture)));
Assert.Equal(dataFile.MD5Hash, hashString);
}
finally
{
if (File.Exists(tempPath))
{
File.Delete(tempPath);
}
}
}
/// <summary>
/// Downloads the specified file from the specified package group as an asynchronous operation.
/// </summary>
/// <param name="service">The Metadata API to use to get the download URI.</param>
/// <param name="fileStore">The file store to register the download with if successfully downloaded.</param>
/// <param name="group">The package group to download the file from.</param>
/// <param name="file">The data file to download.</param>
/// <param name="downloadRootPath">The root path to download data to.</param>
/// <param name="verifyDownloads">Whether to verify file downloads.</param>
/// <param name="cancellationToken">The cancellation token to use to cancel any downloads.</param>
/// <returns>
/// A <see cref="Task"/> representing the asynchronous operation.
/// </returns>
private static async Task DownloadFileAsync(
IMetadataApi service,
IFileStore fileStore,
PackageGroup group,
DataFile file,
string downloadRootPath,
bool verifyDownloads,
CancellationToken cancellationToken)
{
if (cancellationToken.IsCancellationRequested)
{
return;
}
Console.WriteLine("File name: {0}", file.FileName);
Console.WriteLine("File hash: {0}", file.MD5Hash);
Console.WriteLine("File size: {0:N0}", file.Size);
// Query the URIs to download the file from
Uri uri = await service.GetDownloadUriAsync(file.FileName, file.MD5Hash);
if (uri == null)
{
Console.WriteLine("File '{0}' is not available for download at this time.", file.FileName);
Console.WriteLine();
return;
}
Console.WriteLine("File URI: {0}", uri);
Console.WriteLine();
// Create the path to the directory to download the file to
string directoryPath = Path.Combine(
downloadRootPath,
group.PackageGroupCode,
group.Vintage);
string filePath = Path.GetFullPath(Path.Combine(directoryPath, file.FileName));
// Create the directory if it doesn't already exist
if (!Directory.Exists(directoryPath))
{
Directory.CreateDirectory(directoryPath);
}
// Download the file
Console.WriteLine("Downloading '{0}' ({1}) to '{2}'...", file.FileName, file.MD5Hash, filePath);
using (HttpClient client = new HttpClient())
{
using (HttpResponseMessage response = await client.GetAsync(uri, cancellationToken))
{
response.EnsureSuccessStatusCode();
using (Stream stream = await response.Content.ReadAsStreamAsync())
{
using (Stream fileStream = File.Open(filePath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.None))
{
// Ensure any existing file is overwritten
fileStream.SetLength(0L);
await stream.CopyToAsync(fileStream, 4096, cancellationToken);
}
}
}
}
// Validate the download is correct, if configured.
// Don't register the file in the file store as the file download became corrupted somehow.
if (!verifyDownloads || VerifyDownload(filePath, file.MD5Hash))
{
// Register the file with the file store so further invocations
// of the application don't unnecessarily download the file again
fileStore.RegisterFile(file.MD5Hash, filePath);
}
}
