API login and authorization

logging in to the spotify API, as well as authorizing use on mobile webview browsers

MauiProgram.cs

@@ -10,7 +10,7 @@ global using CommunityToolkit.Mvvm.Input;
 global using CommunityToolkit.Mvvm.ComponentModel;
 
 global using Microsoft.Maui.Controls;
-
+global using app.Services;
 
 namespace app;
 
@@ -29,6 +29,9 @@ public static class MauiProgram {
 #endif
         builder.Services.AddTransient<LoginView>();
         builder.Services.AddTransient<LoginViewModel>();
+
+        builder.Services.AddSingleton<ISpotifyService, SpotifyService>();
+
         return builder.Build();
     }
 }

Models/AuthResult.cs

@@ -0,0 +1,13 @@
+using System;
+using System.Text.Json.Serialization;
+
+namespace app.Models;
+
+public record AuthResult {
+
+    [JsonPropertyName("access_token")]
+    public string AccessToken { get; set; }
+    [JsonPropertyName("refresh_token")]
+    public string RefreshToken { get; set; }
+
+}

Services/ISpotifyService.cs

@@ -0,0 +1,9 @@
+using System;
+namespace app.Services;
+
+public interface ISpotifyService {
+
+    Task<bool> Initialize(string authCode);
+
+}
+

Services/SpotifyService.cs

@@ -0,0 +1,38 @@
+using System.Text;
+using System.Text.Json;
+using app.Models;
+
+namespace app.Services;
+
+public class SpotifyService : ISpotifyService {
+    private string accessToken;
+
+    public SpotifyService() {
+    }
+
+    public async Task<bool> Initialize(string authCode) {
+
+        var bytes = Encoding.UTF8.GetBytes($"{Constants.SpotifyClientId}:{Constants.SpotifyClientSecret}");
+        var authHeader = Convert.ToBase64String(bytes);
+
+        var client = new HttpClient();
+        client.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Basic", authHeader);
+
+        var content = new FormUrlEncodedContent(new List<KeyValuePair<string, string>>() {
+            new("code", authCode),
+            new("redirect_uri", Constants.RedirectUrl),
+            new("grant_type", "authorization_code")
+        });
+
+        var response = await client.PostAsync("https://accounts.spotify.com/api/token", content);
+
+        var json = await response.Content.ReadAsStringAsync();
+
+        //deserializing token
+        var result = JsonSerializer.Deserialize<AuthResult>(json);
+
+        accessToken = result.AccessToken;
+        return response.IsSuccessStatusCode;
+    }
+}
+

ViewModels/LoginViewModel.cs

@@ -2,15 +2,24 @@
 
 //partial class in order to be able to use source generators
 public partial class LoginViewModel : ViewModel {
-    public LoginViewModel() {
+
+    private readonly ISpotifyService spotifyService;
+
+    public LoginViewModel(ISpotifyService spotifyService) {
+        this.spotifyService = spotifyService;
     }
 
     [ObservableProperty]
     private bool showLogin;
 
+
     [RelayCommand]
     private void OpenLogin() {
         ShowLogin = true;
     }
 
+    public async Task HandleAuthCode(string authCode) {
+        await spotifyService.Initialize(authCode);
+    }
+
 }

Views/LoginView.xaml.cs

@@ -50,8 +50,26 @@ public partial class LoginView {
         }
     }
 
-    private void LoginWeb_Navigating(object sender, WebNavigatingEventArgs e) {
-        throw new NotImplementedException();
+    private async void LoginWeb_Navigating(object sender, WebNavigatingEventArgs e) {
+        //check if the URL is the redirect URL set up within the Spotify application online
+        //in order to avoid catching the login URL
+        if (!e.Url.Contains("redirect_uri") && e.Url.Contains("https://app/login")) {
+            var queryString = e.Url.Split("?").Last();
+            var parts = queryString.Split("&");
+
+            var parameters = parts.Select(x => x.Split("=")).ToDictionary(x => x.First(), x => x.Last());
+
+            var code = parameters["code"];
+            var returnState = parameters["state"];
+
+            //animating the login portal
+            if (returnState == state && !string.IsNullOrWhiteSpace(code)) {
+                _ = Task.Run(async () => await loginViewModel.HandleAuthCode(code));
+
+                await Login.TranslateTo(Login.X, this.Height, easing: Easing.Linear);
+                Login.IsVisible = false;
+            }
+        }
     }
 
 }

app.csproj

@@ -61,9 +61,13 @@
 	  <None Remove="Views\" />
 	  <None Remove="ViewModels\" />
 	  <None Remove="Resources\Images\8bb41020a6234deba9e51a50ccabda32-removebg-preview.png" />
+	  <None Remove="Services\" />
+	  <None Remove="Models\" />
 	</ItemGroup>
 	<ItemGroup>
 	  <Folder Include="Views\" />
 	  <Folder Include="ViewModels\" />
+	  <Folder Include="Services\" />
+	  <Folder Include="Models\" />
 	</ItemGroup>
 </Project>

app.sln

@@ -0,0 +1,27 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 17.0.31611.283
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "app", "app\app.csproj", "{E40CBDBA-2A17-477A-B283-EB69BD81D28E}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Release|Any CPU.Build.0 = Release|Any CPU
+		{E40CBDBA-2A17-477A-B283-EB69BD81D28E}.Release|Any CPU.Deploy.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {61F7FB11-1E47-470C-91E2-47F8143E1572}
+	EndGlobalSection
+EndGlobal

bin/Debug/net7.0-ios/iossimulator-x64/err.log

@@ -1,2 +1,2 @@
-objc[61091]: Class CDPCAReporter is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDPInternal.framework/CoreCDPInternal (0x15abd51d8) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDP.framework/CoreCDP (0x15376aeb0). One of the two will be used. Which one is undefined.
-objc[61091]: Class CDPCABackupRecoveryReporter is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDPInternal.framework/CoreCDPInternal (0x15abd5ef8) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDP.framework/CoreCDP (0x15376b0e0). One of the two will be used. Which one is undefined.
+objc[93152]: Class CDPCAReporter is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDPInternal.framework/CoreCDPInternal (0x15a5131d8) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDP.framework/CoreCDP (0x1530a8eb0). One of the two will be used. Which one is undefined.
+objc[93152]: Class CDPCABackupRecoveryReporter is implemented in both /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDPInternal.framework/CoreCDPInternal (0x15a513ef8) and /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Library/Developer/CoreSimulator/Profiles/Runtimes/iOS.simruntime/Contents/Resources/RuntimeRoot/System/Library/PrivateFrameworks/CoreCDP.framework/CoreCDP (0x1530a90e0). One of the two will be used. Which one is undefined.

obj/Debug/net7.0-ios/iossimulator-x64/app.csproj.CoreCompileInputs.cache

@@ -1 +1 @@
-98378c31f6eaabff58f5bba47fe4fafa9dbcc3d9
+634e2a0b790f7685ed393364c3f302be7651311d