WebHooks in ASP.NET

I mostly discuss code for ASP.NET Framework but most if not all is interchangeable with ASP.NET Core.

The following official blog post document most of the setting up:

Sending WebHooks with ASP.NET WebHooks and custom filters

Storing WebHook Registrations in SQL

NotifyAllAsync

NotifyAsync just notifies same user. NotifyAllAsync notifies all users. Both can have further filtering via predicate, see: new-year-updates-to-asp-net-webhooks-preview

noecho?

Without this param on the register request the WebHookUri will need to respond to an echo request to prove its alive. Append noecho? to the end of your WebHookUri to prevent this behaviour.

For example: http://localhost:59927/api/webhooks/incoming/custom?noecho

Not sure if actually documented I think I reverse engineered this from the source code, see: WebHookManager.cs#L201

Subscriber identifier/userid resolution

ApiControllerExtensions.cs#L88

WebHookUser.cs#L43

WebHookUser.IdClaimsType

Initializes and overrides this: WebHookUser.cs#L26

See below example in Startup.cs

Startup.cs

// Initialize MS WebHook Apis.
config.InitializeCustomWebHooks();
config.InitializeCustomWebHooksSqlStorage();
config.InitializeCustomWebHooksApis();

// Override the default subscriber identifier key.
// This goes into the "WebHooks" table under the "User" column.
WebHookUser.IdClaimsType = CustomClaimTypes.MyCustomId;

Duplicate registrations

Duplicate WebHook registrations for same user: aspnet/WebHooks/issues/100

I ended up creating a custom check for this.

You can disable encryption on the table for easier debugging using: config.InitializeCustomWebHooksSqlStorage(false);