private async Task <(Stream stream, bool fromStorage)> GetContextStreamAsync(
TournamentBracketRequest request,
TournamentBracketContent content,
CompositeDisposable disposables,
CancellationToken cancellationToken
)
{
// Validate parameters.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (disposables == null)
{
throw new ArgumentNullException(nameof(disposables));
}
// The algorithm is this:
// If there is content, use that.
// If there is not content, then try to get from challonge.
// If there is no content, try to get from persistence
// If it can't be retrieved, throw.
// Check the request for content.
if (content != null &&
content.MediaType.Type == "text" &&
content.MediaType.SubTypeWithoutSuffix == "html"
)
{
// Return a streamreader.
return(content.Content, false);
}
// Try and get it from challonge.
Stream stream = await GetStreamFromChallongeAsync(
request, disposables, cancellationToken
)
.ConfigureAwait(false);
// If not null, return.
if (stream != null)
{
return(stream, false);
}
// Get the reader from storage.
stream = await GetStreamFromStorageAsync(
request, disposables, cancellationToken
).ConfigureAwait(false);
// If there is no stream at this point, throw.
if (stream == null)
{
throw new InvalidOperationException(
$"Could not retrieve content for URL \"{request.Url}\" from user-sumbmitted content, Challonge, or storage.");
}
// Return the reader.
return(stream, true);
}
private Task PersistContentAsync(
TournamentBracketRequest request,
Stream stream,
CancellationToken cancellationToken
)
{
// Validate parameters.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (stream == null)
{
throw new ArgumentNullException(nameof(stream));
}
// Get the container reference.
CloudBlobContainer container = GetStorageContainerReference();
// Get the blob filename.
string file = GetBlobFilename(request);
// Create the block blob.
CloudBlockBlob blob = container.GetBlockBlobReference(file);
// Upload the stream to the blob.
return(blob.UploadFromStreamAsync(stream, cancellationToken));
}
private static string GetBlobFilename(TournamentBracketRequest request)
{
// Validate parameters.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
// The filename will be based on the type.
// Fir single stage tournaments, it will be.
//
// t/<host>?/<id>.html
//
// If there is no host, we will use "(root)" as the host
// ID is the query string.
// Look at the hostname of the URL to get the host.
//
// TODO: Handle event brackets.
string host = "(root)";
// Is it not challonge in it's entirety?
if (string.Compare(request.Url.Host, "challonge.com", StringComparison.OrdinalIgnoreCase) != 0)
{
// Split the host.
ReadOnlySpan <string> parts = request.Url.Host.Split('.');
// If there are not three parts, throw.
if (parts.Length != 3)
{
throw new InvalidOperationException($"The URL { request.Url } is not a valid Challonge URL.");
}
// Set the host with the first part.
host = parts[0].ToLowerInvariant();
}
// Get the path. Lowercase, and set the extension.
string path = Path.ChangeExtension(request.Url.AbsolutePath.ToLowerInvariant(), ".html");
// If there are separators in the path, throw.
// There is one at the beginning.
if (path.IndexOf('/') >= 1)
{
throw new InvalidOperationException($"The URL { request.Url } is not a valid Challonge URL.");
}
// Put it all together.
return($"t/{host}{path}");
}
private async Task <Stream> GetStreamFromStorageAsync(
TournamentBracketRequest request,
CompositeDisposable disposables,
CancellationToken cancellationToken
)
{
// Validate parameters.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
if (disposables == null)
{
throw new ArgumentNullException(nameof(disposables));
}
// Get the container reference.
CloudBlobContainer container = GetStorageContainerReference();
// Get the blob filename.
string file = GetBlobFilename(request);
// Create the block blob.
CloudBlockBlob blob = container.GetBlockBlobReference(file);
// Does it exist? If not, return null.
if (!await blob.ExistsAsync(cancellationToken)
.ConfigureAwait(false))
{
return(null);
}
// The stream to be a target.
var ms = new MemoryStream();
// Add to the disposables.
disposables.Add(ms);
// Download.
await blob.DownloadToStreamAsync(ms, cancellationToken)
.ConfigureAwait(false);
// Reset the stream.
ms.Position = 0;
// Return the stream.
return(ms);
}
private async Task <Stream> GetStreamFromChallongeAsync(
TournamentBracketRequest request,
CompositeDisposable disposables,
CancellationToken cancellationToken
)
{
// Validate parameters.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
// Try to get from challonge.
HttpResponseMessage response = await _httpClient
.GetAsync(request.Url, cancellationToken)
.ConfigureAwait(false);
// If there is not a X-Challonge-Cache-ID header, return
// null.
if (!response.Headers.TryGetValues("X-Challonge-Cache-ID", out var _))
{
// Return null.
return(null);
}
// Add to the disposables.
disposables.Add(response);
// Get the stream.
Stream stream = await response.Content
.ReadAsStreamAsync()
.ConfigureAwait(false);
// Return.
return(stream);
}
public async Task <TournamentBracketResponse> GetTournamentBracketAsync(
TournamentBracketRequest request,
TournamentBracketContent content,
CancellationToken cancellationToken)
{
// Validate parameters.
// Note: The content parameter can be null.
if (request == null)
{
throw new ArgumentNullException(nameof(request));
}
// If the url is null, throw.
if (request.Url == null)
{
throw new InvalidOperationException(
$"The {nameof(request.Url)} property on the {nameof(request)} parameter cannot be null.");
}
// The disposables.
using var disposables = new CompositeDisposable();
// The page content.
TournamentBracketPage page;
// Get the content stream.
(Stream rawStream, bool fromStorage) = await GetContextStreamAsync(
request, content, disposables, cancellationToken
).ConfigureAwait(false);
// Add the raw stream to the disposables.
disposables.Add(rawStream);
// If there is no stream, copy it.
if (!(rawStream is MemoryStream stream))
{
// Create a new one.
stream = new MemoryStream();
// Copy.
await rawStream.CopyToAsync(stream, 4096, cancellationToken)
.ConfigureAwait(false);
}
// Add the stream to the disposables.
disposables.Add(stream);
// Set the position of the stream back.
stream.Position = 0;
// Create a reader.
using TextReader reader = new StreamReader(stream);
// Parse.
page = await _parser.ParseTournamentBracketPageAsync(reader, cancellationToken)
.ConfigureAwait(false);
// Everything was successful at this point, reset the stream and persist.
stream.Position = 0;
// Persist if this wasn't from storage to begin with.
if (!fromStorage)
{
await PersistContentAsync(request, stream, cancellationToken)
.ConfigureAwait(false);
}
// Return.
return(new TournamentBracketResponse {
Request = request,
PageContent = page.PageContent,
Bracket = page.Bracket,
TargetingKeyValues = page.TargetingKeyValues,
MetaList = page.MetaList
});
}