Lesson 4: Managing AdMob Credentials in .NET (No Direct Ad Requests)

Meta Description

Learn how to manage Google AdMob credentials in a .NET backend. This guide covers dynamically storing and retrieving AdMob App IDs and Ad Unit IDs, properly configuring Program.cs, and securely managing API requests for monetization tracking.

Why Use a Backend for AdMob Configuration?

Google AdMob does not allow direct ad requests from a backend. Instead, we use the backend to: ✅ Store and manage AdMob credentials dynamically. ✅ Send the correct App ID and Ad Unit IDs to client apps. ✅ Log and track ad interactions (e.g., impressions, clicks, and ad loads). ✅ Control ad behavior dynamically (e.g., disable ads for premium users).

Step 1: Ensure Program.cs is Configured Correctly

Your .NET backend must be configured properly to register controllers and services.

Update Program.cs

Open Program.cs and ensure it has the following code:

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

var builder = WebApplication.CreateBuilder(args);

// Add services to the container.
builder.Services.AddControllers();

var app = builder.Build();

// Configure the HTTP request pipeline.
if (app.Environment.IsDevelopment())
{
    app.UseDeveloperExceptionPage();
}

app.UseHttpsRedirection();
app.UseAuthorization();
app.MapControllers();

app.Run();

Explanation:

• builder.Services.AddControllers(); → Registers controllers.
• app.MapControllers(); → Ensures that API routes are mapped correctly.
• app.UseHttpsRedirection(); → Redirects HTTP to HTTPS automatically.

Step 2: Storing AdMob Configuration Dynamically from the Client

Instead of hardcoding AdMob credentials inside the API, we will allow each app to send its own AdMob settings dynamically via API requests.

Create AdMobConfig.cs Model

Inside your .NET backend project, create a new folder named Models (if it does not exist), then add a file AdMobConfig.cs:

namespace CGZAPI.Models
{
    public class AdMobConfig
    {
        public string AppName { get; set; }
        public string AppId { get; set; }
        public string BannerAdId { get; set; }
        public string InterstitialAdId { get; set; }
        public string RewardedAdId { get; set; }
    }
}

How It Works:

• Each app will send its own AdMob credentials dynamically when making requests.
• The API will store and retrieve these settings based on the AppName.

Step 3: Creating AdMobManager.cs to Store Dynamic Configurations

Inside your .NET backend project, create a new folder named Services (if it does not exist), then add a file AdMobManager.cs:

using System.Collections.Generic;
using CGZAPI.Models;

namespace CGZAPI.Services
{
    public static class AdMobManager
    {
        private static Dictionary<string, AdMobConfig> _adConfigs = new Dictionary<string, AdMobConfig>();

        public static AdMobConfig GetAdMobConfig(string appName)
        {
            return _adConfigs.ContainsKey(appName) ? _adConfigs[appName] : null;
        }

        public static void SetAdMobConfig(AdMobConfig config)
        {
            _adConfigs[config.AppName] = config;
        }
    }
}

Explanation:

• GetAdMobConfig(string appName): Retrieves AdMob settings dynamically.
• SetAdMobConfig(AdMobConfig config): Allows an app to send its own AdMob credentials dynamically.

Step 4: Creating AdMobController.cs to Accept AdMob Settings from the Client

Inside your .NET backend project, create a new folder named Controllers (if it does not exist), then add a file AdMobController.cs:

using Microsoft.AspNetCore.Mvc;
using CGZAPI.Services;
using CGZAPI.Models;

namespace CGZAPI.Controllers
{
    [Route("api/admob")]
    [ApiController]
    public class AdMobController : ControllerBase
    {
        [HttpGet("get-config/{appName}")]
        public IActionResult GetAdConfig(string appName)
        {
            var config = AdMobManager.GetAdMobConfig(appName);
            if (config == null)
                return NotFound("AdMob configuration not found for this app.");
            return Ok(config);
        }

        [HttpPost("set-config")]
        public IActionResult SetAdConfig([FromBody] AdMobConfig config)
        {
            if (config == null || string.IsNullOrEmpty(config.AppName))
                return BadRequest("Invalid AdMob configuration.");
            
            AdMobManager.SetAdMobConfig(config);
            return Ok("AdMob configuration updated successfully.");
        }
    }
}

New Features:

• [HttpPost("set-config")]: Allows an app to send its own AdMob configuration dynamically.
• [FromBody] AdMobConfig config: Extracts the configuration from the request body.

Step 5: How Your Client App Uses the API

✅ Correct Approach

Your backend manages and sends AdMob credentials, while Unity (or any client app) makes ad requests using the AdMob SDK.

1️⃣ Store AdMob Configuration (POST Request)

• Method: POST
• URL: http://localhost:5000/api/admob/set-config
• Body (JSON):

{
    "appName": "DynamicApp",
    "appId": "ca-app-pub-9999999999999999~1234567890",
    "bannerAdId": "ca-app-pub-9999999999999999/1111111111",
    "interstitialAdId": "ca-app-pub-9999999999999999/2222222222",
    "rewardedAdId": "ca-app-pub-9999999999999999/3333333333"
}

2️⃣ Retrieve AdMob Credentials (GET Request)

• Method: GET
• URL: http://localhost:5000/api/admob/get-config/DynamicApp
• Response:

{
    "appName": "DynamicApp",
    "appId": "ca-app-pub-9999999999999999~1234567890",
    "bannerAdId": "ca-app-pub-9999999999999999/1111111111",
    "interstitialAdId": "ca-app-pub-9999999999999999/2222222222",
    "rewardedAdId": "ca-app-pub-9999999999999999/3333333333"
}

3️⃣ Unity Uses AdMob SDK to Request Ads

Your Unity app initializes AdMob SDK using the received credentials and requests ads directly from Google.

Next Steps: Authentication Focus

Since AdMob does not work as expected for direct ad requests, we will now focus on authentication in the next lesson.