Proxy

Application/Configuration/ConfigurationDependencyInjection.cs

@@ -41,5 +41,17 @@ namespace Musify.Application.Configuration
 
             return serviceDescriptors;
         }
+
+        public static IServiceCollection AddStreamGatewayConfiguration(this IServiceCollection serviceDescriptors, IConfiguration configuration)
+        {
+            serviceDescriptors
+                .AddOptionsWithValidateOnStart<StreamGatewayConfiguration>()
+                .Bind(configuration.GetRequiredSection(StreamGatewayConfiguration.SectionName))
+                .ValidateDataAnnotations();
+            serviceDescriptors.AddSingleton(serviceProvider =>
+                serviceProvider.GetRequiredService<IOptions<StreamGatewayConfiguration>>().Value);
+
+            return serviceDescriptors;
+        }
     }
 }

Application/Configuration/StreamGatewayConfiguration.cs

@@ -0,0 +1,16 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Musify.Application.Configuration
+{
+    public class StreamGatewayConfiguration
+    {
+        public const string SectionName = "StreamGateway";
+
+        [Url]
+        [Required]
+        public required string PublicBaseUrl { get; set; }
+
+        [Required]
+        public string ManifestFileName { get; set; } = "manifest.mpd";
+    }
+}

Application/Contracts/IStreamTicketService.cs

@@ -0,0 +1,9 @@
+namespace Musify.Application.Contracts
+{
+    public interface IStreamTicketService
+    {
+        StreamTicket IssueTicket(Guid userId, string keyPrefix);
+    }
+
+    public record StreamTicket(string Token, int ExpiresInSeconds);
+}

Application/Tracks/Handlers/GetTrackStreamQueryHandler.cs

@@ -0,0 +1,54 @@
+using Ardalis.Result;
+using Mediator;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.Logging;
+using Musify.Application.Configuration;
+using Musify.Application.Contracts;
+using Musify.Application.Tracks.Queries;
+using Musify.Application.Tracks.Responses;
+using Musify.Domain.ValueObjects;
+
+namespace Musify.Application.Tracks.Handlers
+{
+    public class GetTrackStreamQueryHandler(
+        IDatabase database,
+        IStreamTicketService ticketService,
+        TrackConfiguration trackConfiguration,
+        StreamGatewayConfiguration streamGatewayConfiguration,
+        ILogger<GetTrackStreamQueryHandler> logger)
+        : IQueryHandler<GetTrackStreamQuery, Result<TrackStreamResponse>>
+    {
+        public async ValueTask<Result<TrackStreamResponse>> Handle(GetTrackStreamQuery request, CancellationToken cancellationToken)
+        {
+            var track = await database.Tracks.AsNoTracking()
+                .Where(t => t.Id == request.TrackId)
+                .Select(t => new { t.Id, t.AudioTranscodeProcessingStatus, t.AudioFolderName })
+                .SingleOrDefaultAsync(cancellationToken);
+
+            if (track is null)
+                return Result<TrackStreamResponse>.NotFound();
+
+            if (string.IsNullOrWhiteSpace(track.AudioFolderName)
+                || track.AudioTranscodeProcessingStatus != ProcessingStatus.Completed)
+            {
+                logger.LogInformation("Stream requested for track {TrackId} but audio is not ready", request.TrackId);
+                return Result<TrackStreamResponse>.Conflict("Track audio is not available for streaming yet.");
+            }
+
+            var folderPath = trackConfiguration.Routes.BuildProcessedAudioPath(track.AudioFolderName);
+            var keyPrefix = $"{folderPath}/";
+
+            var ticket = ticketService.IssueTicket(request.UserId, keyPrefix);
+
+            var manifestUrl = string.Join('/',
+                streamGatewayConfiguration.PublicBaseUrl.TrimEnd('/'),
+                "media",
+                folderPath,
+                streamGatewayConfiguration.ManifestFileName);
+
+            logger.LogInformation("Issued stream ticket for track {TrackId} to user {UserId}", request.TrackId, request.UserId);
+
+            return Result.Success(new TrackStreamResponse(manifestUrl, ticket.Token, ticket.ExpiresInSeconds));
+        }
+    }
+}

Application/Tracks/Queries/GetTrackStreamQuery.cs

@@ -0,0 +1,9 @@
+using Ardalis.Result;
+using Mediator;
+using Musify.Application.Tracks.Responses;
+
+namespace Musify.Application.Tracks.Queries
+{
+    public record GetTrackStreamQuery(Guid TrackId, Guid UserId)
+        : IQuery<Result<TrackStreamResponse>>;
+}

Application/Tracks/Responses/TrackStreamResponse.cs

@@ -0,0 +1,7 @@
+namespace Musify.Application.Tracks.Responses
+{
+    public record TrackStreamResponse(
+        string ManifestUrl,
+        string Ticket,
+        int ExpiresInSeconds);
+}

Infrastructure/Configuration/StreamTicketConfiguration.cs

@@ -0,0 +1,21 @@
+using System.ComponentModel.DataAnnotations;
+
+namespace Musify.Infrastructure.Configuration
+{
+    public class StreamTicketConfiguration
+    {
+        public const string SectionName = "StreamTicket";
+
+        [Required]
+        public required string PrivateKeyPath { get; set; }
+
+        [Required]
+        public string Audience { get; set; } = "media-gateway";
+
+        [Required]
+        public string Issuer { get; set; } = "musify-webapi";
+
+        [Range(60, 86400)]
+        public int TicketTtlSeconds { get; set; } = 3600;
+    }
+}

Infrastructure/Infrastructure.csproj

@@ -26,6 +26,7 @@
     <PackageReference Include="Microsoft.Extensions.Configuration.FileExtensions" Version="10.0.8" />
     <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="10.0.8" />
     <PackageReference Include="Microsoft.Extensions.Configuration.UserSecrets" Version="10.0.8" />
+    <PackageReference Include="Microsoft.IdentityModel.JsonWebTokens" Version="8.14.0" />
     <PackageReference Include="MimeMapping" Version="4.0.0" />
     <PackageReference Include="Npgsql.EntityFrameworkCore.PostgreSQL" Version="10.0.2" />
     <PackageReference Include="OpenTelemetry.Exporter.OpenTelemetryProtocol" Version="1.15.3" />

Infrastructure/Services/ServicesDependencyInjection.cs

@@ -71,6 +71,20 @@ namespace Musify.Infrastructure.Services
             return serviceDescriptors;
         }
 
+        public static IServiceCollection AddStreamTicketService(this IServiceCollection serviceDescriptors, IConfiguration configuration)
+        {
+            serviceDescriptors
+                .AddOptionsWithValidateOnStart<StreamTicketConfiguration>()
+                .Bind(configuration.GetRequiredSection(StreamTicketConfiguration.SectionName))
+                .ValidateDataAnnotations();
+
+            serviceDescriptors.AddSingleton(serviceProvider =>
+                serviceProvider.GetRequiredService<IOptions<StreamTicketConfiguration>>().Value);
+
+            serviceDescriptors.AddSingleton<IStreamTicketService, StreamTicketService>();
+            return serviceDescriptors;
+        }
+
         public static IServiceCollection AddAudioTranscoder(this IServiceCollection serviceDescriptors, IConfiguration configuration)
         {
             serviceDescriptors

Infrastructure/Services/StreamTicketService.cs

@@ -0,0 +1,52 @@
+using System.Security.Cryptography;
+using Microsoft.IdentityModel.JsonWebTokens;
+using Microsoft.IdentityModel.Tokens;
+using Musify.Application.Contracts;
+using Musify.Infrastructure.Configuration;
+
+namespace Musify.Infrastructure.Services
+{
+    public sealed class StreamTicketService : IStreamTicketService, IDisposable
+    {
+        private readonly StreamTicketConfiguration configuration;
+        private readonly RSA rsa;
+        private readonly SigningCredentials signingCredentials;
+        private readonly JsonWebTokenHandler tokenHandler = new();
+
+        public StreamTicketService(StreamTicketConfiguration configuration)
+        {
+            this.configuration = configuration;
+
+            rsa = RSA.Create();
+            rsa.ImportFromPem(File.ReadAllText(configuration.PrivateKeyPath));
+
+            var key = new RsaSecurityKey(rsa);
+            signingCredentials = new SigningCredentials(key, SecurityAlgorithms.RsaSha256);
+        }
+
+        public StreamTicket IssueTicket(Guid userId, string keyPrefix)
+        {
+            var now = DateTimeOffset.UtcNow;
+
+            var descriptor = new SecurityTokenDescriptor
+            {
+                Issuer = configuration.Issuer,
+                Audience = configuration.Audience,
+                IssuedAt = now.UtcDateTime,
+                NotBefore = now.UtcDateTime,
+                Expires = now.AddSeconds(configuration.TicketTtlSeconds).UtcDateTime,
+                Claims = new Dictionary<string, object>
+                {
+                    ["sub"] = userId.ToString(),
+                    ["prefix"] = keyPrefix,
+                },
+                SigningCredentials = signingCredentials,
+            };
+
+            var token = tokenHandler.CreateToken(descriptor);
+            return new StreamTicket(token, configuration.TicketTtlSeconds);
+        }
+
+        public void Dispose() => rsa.Dispose();
+    }
+}