/// <summary>
/// Gets a valid <see cref="Response"/> or requests and caches a <see cref="CachedResponse"/>.
/// </summary>
/// <param name="isAsync">Whether certain operations should be performed asynchronously.</param>
/// <param name="uri">The URI sans query parameters to cache.</param>
/// <param name="action">The action to request a response.</param>
/// <returns>A new <see cref="Response"/>.</returns>
internal async ValueTask <Response> GetOrAddAsync(bool isAsync, string uri, TimeSpan ttl, Func <ValueTask <Response> > action)
{
if (isAsync)
{
await _lock.WaitAsync().ConfigureAwait(false);
}
else
{
_lock.Wait();
}
try
{
// Try to get a valid cached response inside the lock before fetching.
if (_cache.TryGetValue(uri, out CachedResponse cachedResponse) && cachedResponse.IsValid)
{
return(await cachedResponse.CloneAsync(isAsync).ConfigureAwait(false));
}
Response response = await action().ConfigureAwait(false);
if (response.Status == 200 && response.ContentStream is { })
{
cachedResponse = await CachedResponse.CreateAsync(isAsync, response, ttl).ConfigureAwait(false);
_cache[uri] = cachedResponse;
}
return(response);
}
private static async ValueTask <CachedResponse> CloneAsync(bool isAsync, Response response)
{
CachedResponse cachedResponse = new CachedResponse(response.Status, response.ReasonPhrase, response.Headers)
{
ClientRequestId = response.ClientRequestId,
};
if (response.ContentStream is { })
internal static async ValueTask <CachedResponse> CreateAsync(bool isAsync, Response response, TimeSpan ttl)
{
CachedResponse cachedResponse = await CloneAsync(isAsync, response).ConfigureAwait(false);
cachedResponse._expires = DateTimeOffset.Now + ttl;
return(cachedResponse);
}
