I have two Asp.Net web apps, App 1 and App 2. They both use the same database. I am trying to give command from App 1 and immediately run a bit of code in App 2.
The only way I can think of doing this is by inserting a command in the database and have App 2 poll the database every few minutes. But this means there may be a delay in running the code.
Is there a way to run code in App 2 immediately?
You can fire an HttpRequest from one app to another and the code will run almost immediately.
I don't know what language and platform you're using, so it's hard to give you concrete examples, but here are the outlines:
Create a page in App2. In standard ASP.Net, you can use a handler. In ASP Core, you can use an API controller. Both car return a single value or a full object in JSON or XML. Or you can use a standard page if you like to return HTML. The code behind is what you want to run. The rendered page or return value from the handler or controller is what you want App1 to get back in response.
Then from App1, issue an HttpRequest to that page in App2 and check the response to see how to continue (for example, if the code ran successfully or not).
The HttpRequest is in case you want to make the call from the server side of App1. If you want to make the call from the client side, then you use Ajax instead. In the case of Ajax, you have to pay attention to the security side, because you don't want to allow whoever to call that page from App2 unless it unless the code behind doesn't pose any security risk and doesn't return any sensitive data.
One last idea specific to your scenario, since both apps are using the same database, you can add the required values to the database as you were planning to do, and then issue a simple HttpRequest. This way, you don't need to worry about security or passing a any sensitive info. When App2 receives the request, it checks the database to see if the request was actually made from App1 and then processes it, otherwise ignores it.