private static async Task <string> DiscoverServiceAccountIdAsync(
HttpClientFactory clientFactory)
{
using (var client = clientFactory.CreateDefaultHttpClient())
{
client.DefaultRequestHeaders.Add("Metadata-Flavor", "Google");
return(await client.GetStringAsync(MetadataServerUrl).ConfigureAwait(false));
}
}
public async Task <IReadOnlyList <PublicKey> > GetPublicKeysAsync(
CancellationToken cancellationToken = default(CancellationToken))
{
if (_cachedKeys == null || _clock.UtcNow >= _expirationTime)
{
await _lock.WaitAsync(cancellationToken).ConfigureAwait(false);
try
{
var now = _clock.UtcNow;
if (_cachedKeys == null || now >= _expirationTime)
{
using (var httpClient = _clientFactory.CreateDefaultHttpClient())
{
var response = await httpClient.GetAsync(_certUrl, cancellationToken)
.ConfigureAwait(false);
response.EnsureSuccessStatusCode();
_cachedKeys = ParseKeys(await response.Content.ReadAsStringAsync()
.ConfigureAwait(false));
var cacheControl = response.Headers.CacheControl;
if (cacheControl?.MaxAge != null)
{
_expirationTime = now.Add(cacheControl.MaxAge.Value)
.Subtract(ClockSkew);
}
}
}
}
catch (HttpRequestException e)
{
throw new FirebaseException("Failed to retrieve latest public keys.", e);
}
finally
{
_lock.Release();
}
}
return(_cachedKeys);
}
