internal static RestServiceCollection Create(IEnumerable <FileDescriptor> fileDescriptors)
{
var services = fileDescriptors.SelectMany(file => file.Services);
var typeRegistry = TypeRegistry.FromFiles(fileDescriptors.ToArray());
var parser = new JsonParser(JsonParser.Settings.Default.WithIgnoreUnknownFields(true).WithTypeRegistry(typeRegistry));
var methodsByName = services.SelectMany(service => service.Methods)
.Where(x => true) // TODO: filter out streaming methods.
.Select(method => RestMethod.Create(method, parser))
.ToDictionary(restMethod => restMethod.FullName);
return(new RestServiceCollection(new ReadOnlyDictionary <string, RestMethod>(methodsByName)));
}
private async Task AddAuthHeadersAsync(HttpRequestMessage request, RestMethod method)
{
Uri hostUri = request.RequestUri.IsAbsoluteUri ? request.RequestUri : _httpClient.BaseAddress;
string schemeAndAuthority = hostUri.GetLeftPart(UriPartial.Authority);
var metadata = new Metadata();
var context = new AuthInterceptorContext(schemeAndAuthority, method.FullName);
await _channelAuthInterceptor(context, metadata).ConfigureAwait(false);
foreach (var entry in metadata)
{
request.Headers.Add(entry.Key, entry.Value);
}
}
private async Task <ReadHttpResponseMessage> SendAsync <TRequest>(RestMethod restMethod, string host, CallOptions options, TRequest request, CancellationToken deadlineToken)
{
// Ideally, add the header in the client builder instead of in the ServiceSettingsBase...
var httpRequest = restMethod.CreateRequest((IMessage)request, host);
foreach (var headerKeyValue in options.Headers
.Where(mh => !mh.IsBinary)
.Where(mh => mh.Key != VersionHeaderBuilder.HeaderName))
{
httpRequest.Headers.Add(headerKeyValue.Key, headerKeyValue.Value);
}
httpRequest.Headers.Add(VersionHeaderBuilder.HeaderName, RestVersion);
HttpResponseMessage httpResponseMessage;
using (CancellationTokenSource linkedCts = CancellationTokenSource.CreateLinkedTokenSource(options.CancellationToken, deadlineToken))
{
try
{
await AddAuthHeadersAsync(httpRequest, restMethod, linkedCts.Token).ConfigureAwait(false);
httpResponseMessage = await _httpClient.SendAsync(httpRequest, HttpCompletionOption.ResponseContentRead, linkedCts.Token).ConfigureAwait(false);
}
catch (TaskCanceledException ex) when(deadlineToken.IsCancellationRequested)
{
throw new RpcException(new Status(StatusCode.DeadlineExceeded, $"The timeout was reached when calling a method `{restMethod.FullName}`", ex));
}
}
try
{
string content = await httpResponseMessage.Content.ReadAsStringAsync().ConfigureAwait(false);
return(new ReadHttpResponseMessage(httpResponseMessage, content));
}
catch (Exception ex)
{
// Let's defer the throwing of this exception to when it's actually needed,
// so that we can at least read headers and other metadata.
var exInfo = ExceptionDispatchInfo.Capture(ex);
return(new ReadHttpResponseMessage(httpResponseMessage, exInfo));
}
}
private async Task <HttpResponseMessage> SendAsync <TRequest>(RestMethod restMethod, string host, CallOptions options, TRequest request, CancellationToken cancellationToken)
{
// Ideally, add the header in the client builder instead of in the ServiceSettingsBase...
// TODO: Use options. How do we set the timeout for an individual HTTP request? We probably need to create a linked cancellation token.
var httpRequest = restMethod.CreateRequest((IMessage)request, host);
foreach (var headerKeyValue in options.Headers
.Where(mh => !mh.IsBinary)
.Where(mh => mh.Key != VersionHeaderBuilder.HeaderName))
{
httpRequest.Headers.Add(headerKeyValue.Key, headerKeyValue.Value);
}
httpRequest.Headers.Add(VersionHeaderBuilder.HeaderName, RestVersion);
// TODO: How do we cancel this?
await AddAuthHeadersAsync(httpRequest, restMethod).ConfigureAwait(false);
var task = _httpClient.SendAsync(httpRequest, HttpCompletionOption.ResponseContentRead, cancellationToken);
return(await task.ConfigureAwait(false));
}
private async Task AddAuthHeadersAsync(HttpRequestMessage request, RestMethod restMethod, CancellationToken combinedCancellationToken)
{
Uri hostUri = request.RequestUri.IsAbsoluteUri ? request.RequestUri : _httpClient.BaseAddress;
string schemeAndAuthority = hostUri.GetLeftPart(UriPartial.Authority);
var metadata = new Metadata();
var context = new AuthInterceptorContext(schemeAndAuthority, restMethod.FullName);
var combinedCancellationTask = Task.Delay(-1, combinedCancellationToken);
var channelTask = _channelAuthInterceptor(context, metadata);
var resultTask = await Task.WhenAny(channelTask, combinedCancellationTask).ConfigureAwait(false);
// If the combinedCancellationTask "wins" `Task.WhenAny` by being cancelled, the following await will throw TaskCancelledException.
// If the channelTask "wins" by being faulted, the await will rethrow its exception.
// Finally, if the channelTask completes, the await does nothing.
await resultTask.ConfigureAwait(false);
// If we're here, the channelTask has completed successfully.
foreach (var entry in metadata)
{
request.Headers.Add(entry.Key, entry.Value);
}
}