Plex.Extensions.DbContext 8.0.24

Plex.Extensions.DbContext

A .NET 8 library that simplifies EF Core DbContext registration with Microsoft Dependency Injection. It supports SQL Server and PostgreSQL, dynamic per-request connection strings (multi-tenant), optional EF Core interceptors (caching), and raw SQL connection factories for Dapper.

Features

• DbContext registration — pooled (AddDbContextPool) or standard (AddDbContext) with a single method call
• Multi-provider — SQL Server and PostgreSQL, switchable per database via configuration
• Dynamic connection strings — resolve different databases per HTTP request using cx-db and cx-server headers (multi-tenant)
• EF Core options from config — command timeout, retry-on-failure, lazy loading, change tracking, query tracking, and migrations all driven by appsettings.json
• Cache interceptor support — optionally wire a DbCommandInterceptor for query caching
• Raw SQL connection factory — register IDbConnection implementations (e.g., for Dapper) with the same dynamic connection string logic
• Assembly scanning — auto-register all implementations of an interface from specified assemblies

Installation

dotnet add package Plex.Extensions.DbContext

Configuration

Add these settings to your appsettings.json (all are optional — defaults shown):

{
  "ConnectionStringKey": "DefaultConnection",
  "ConnectionStrings": {
    "DefaultConnection": "Server=%server%;Database=%db%;Trusted_Connection=True;"
  },
  "EfSqlCommandTimeOutInSecond": 300,
  "EfSqlMaxRetryOnFailureCount": 0,
  "EfEnableMigration": false,
  "EfUseLazyLoading": false,
  "EfUseChangeTrackingProxies": false,
  "EfUseQueryTrackingBehavior": false,
  "AppSettings": {
    "DbProviderMappings": {
      "my-database-name": "mssql",
      "my-pg-database": "postgresql"
    }
  }
}

Usage

Register a single DbContext (pooled)

// In Program.cs or Startup.cs
builder.Services.RegisterDbContextPool<MyDbContext>();

This registers MyDbContext as a pooled DbContext with all EF options resolved from configuration.

Register a single DbContext (standard)

builder.Services.RegisterDbContext<MyDbContext>();

Register with a cache interceptor

// Pooled
builder.Services.RegisterDbContextPool<MyDbContext, MyCacheInterceptor>();

// Standard
builder.Services.RegisterDbContext<MyDbContext, MyCacheInterceptor>();

The interceptor (DbCommandInterceptor) is resolved from DI and added to the DbContext options if registered.

Register multiple DbContexts

builder.Services.RegisterDbContextsPool(services =>
{
    var key = services.RegisterDbContextPool<FirstDbContext>();
    key = services.RegisterDbContextPool<SecondDbContext>(key);
    return key;
});

Register a raw SQL connection factory (for Dapper)

builder.Services.RegisterSqlConnectionFactory<ISqlConnectionFactory, SqlConnectionFactory>();

This creates a connection with the dynamically resolved connection string, automatically appending Command Timeout and TrustServerCertificate=True if not already present.

Assembly scanning

builder.Services.RegisterFromAssemblyTypes<IMyService>(
    typeof(MyServiceImpl).Assembly
);

Scans the given assemblies for all types implementing IMyService and registers them as scoped services.

Dynamic Connection Strings (Multi-Tenant)

The library supports per-request database targeting via HTTP headers:

Connection string templates can use %db% and %server% placeholders that get replaced at runtime. Resolved connection strings are cached in memory for performance.

API Reference

ServiceCollectionExtensions

ConfigurationExtensions

PlexDbOptions

Configuration object registered in DI that holds all EF Core settings and the resolved connection string for the current request.

Dependencies

License

Plex-Solution Community Source-Available License — free for non-commercial use only.