/// <summary>
/// Reads the current state of the entity, applies a change to it and stores the result. Applies optimistic concurrency using automatic retries.
/// </summary>
/// <typeparam name="TEntity">The type of entity the endpoint represents.</typeparam>
/// <param name="endpoint">The endpoint representing the entity.</param>
/// <param name="updateAction">A callback that takes the current state of the entity and applies the desired modifications.</param>
/// <param name="maxRetries">The maximum number of retries to perform for optimistic concurrency before giving up.</param>
/// <param name="cancellationToken">Used to cancel the request.</param>
/// <returns>The <typeparamref name="TEntity"/> as returned by the server, possibly with additional fields set. <c>null</c> if the server does not respond with a result entity.</returns>
/// <exception cref="InvalidDataException"><see cref="HttpStatusCode.BadRequest"/></exception>
/// <exception cref="AuthenticationException"><see cref="HttpStatusCode.Unauthorized"/></exception>
/// <exception cref="UnauthorizedAccessException"><see cref="HttpStatusCode.Forbidden"/></exception>
/// <exception cref="KeyNotFoundException"><see cref="HttpStatusCode.NotFound"/> or <see cref="HttpStatusCode.Gone"/></exception>
/// <exception cref="InvalidOperationException">The number of retries performed for optimistic concurrency exceeded <paramref name="maxRetries"/>.</exception>
/// <exception cref="HttpRequestException">Other non-success status code.</exception>
public static async Task <TEntity> UpdateAsync <TEntity>(this IElementEndpoint <TEntity> endpoint, Action <TEntity> updateAction, int maxRetries = 3, CancellationToken cancellationToken = default)
{
int retryCounter = 0;
while (true)
{
var entity = await endpoint.ReadAsync(cancellationToken);
cancellationToken.ThrowIfCancellationRequested();
updateAction(entity);
cancellationToken.ThrowIfCancellationRequested();
try
{
return(await endpoint.SetAsync(entity, cancellationToken));
}
catch (InvalidOperationException)
{
if (retryCounter++ >= maxRetries)
{
throw;
}
cancellationToken.ThrowIfCancellationRequested();
}
}
}
public async Task TestRead()
{
Mock.Expect(HttpMethod.Get, "http://localhost/endpoint")
.Respond(JsonMime, "{\"id\":5,\"name\":\"test\"}");
var result = await _endpoint.ReadAsync();
result.Should().Be(new MockEntity(5, "test"));
}
/// <summary>
/// Gets a specific <see cref="RecordSet"/> identified by a <paramref name="recordSetName"/>.
/// </summary>
/// <exception cref="RecordSetNotFoundException"></exception>
public static async Task <RecordSet> GetRecordSetAsync(this IElementEndpoint <Zone> endpoint,
CanonicalName recordSetName,
CancellationToken cancellationToken = default)
{
var zone = await endpoint.ReadAsync(cancellationToken);
var recordSet = zone.RecordSets.FirstOrDefault(rrs => rrs.Name.Equals(recordSetName));
if (recordSet == null)
{
throw new RecordSetNotFoundException(recordSetName);
}
return(recordSet);
}