Hi Folks! In this post I will show you how to retrieve the user's geolocation from their IP address in a .NET7 application. This application relies on multiple geolocation providers (IPInfoDb being one of them and requiring registration in order to function properly) and a custom middleware, to execute the service(s) for each and every request.

First, let's start off with cloning the github repository:

Before running the application, you need to register yourself on IpInfoDb to get an API Key.

You can clone the repository here.

Open the NET7-IPGeolocation.sln solution file and go straight to the ILocationService interface (the heart of the whole thing), inside Services.IPLocation project. You will notice that the interface defines the contract for a service of the ip-geolocation. The most important one being the Find method (that actually calls the provider themselves to retrieve the location).

Basically, that interface contains objects for thresholds, API limits, number of successful and unsuccessful calls; and where the service should save their information in cache (keys). Most of the implementation can be seen inside the abstract LocationService class. But there's 5 concrete classes implementing the ip-geolocation service:

1. DummyIp - do not use;
2. FreeGeoIp - decomissioned, do not use;
3. GeoPlugin;
4. IpApi; and
5. IpInfoDb.

You can always create a new concrete LocationService class for a provider of your choosing.

So now, let's take a look at the custom middleware, called LocationMiddleware, orchestrating the calls and which instance of the service to use (there's an extension method called Next inside the Extensions.cs file of the Services.IPLocation project. Head to the Location webapplication project and a folder called Middleware, there will only be one file there.

As you can see, there dependency injection in the constructor of the middleware, one for the request pipeline (default for a middleware) and another one for the implementers of the ILocationService. At the execution of the request, the middleware tries to retrieve the real ip address of the client (because the local ip address will always be ::1) and then retrieve the appropriate ILocationService instance from the collection.

After calling the Find method and obtaining the location, it saves the information in session (before heading to the next request middleware).

Now, go to the Program.cs file inside the Location web application. At the end of it, you will see a MapGet call for the "/" path, basically getting the information back from Session and returning the user's location in a string form. 

Before running the application, you need to register yourself on IpInfoDb to get an API Key.

Aftet that, you need to replace "INSERT YOUR KEY HERE" string inside the Program.cs file in the Location project.

Run the application, you should see a page in your browser stating your current location (from your IP address alone, no location sharing necessary).

Hope you guys enjoyed it. See ya!