David Fowler davidfowl

Distinguished Engineer 🧐 at Microsoft on the .NET team, Creator of SignalR

davidfowl / FromSqlInterpolatedStringHandler.cs

Last active May 12, 2025 07:08

Implementation of parameterized sql queries using string interpolation handlers

	using System.Data.Common;
	using System.Runtime.CompilerServices;
	using System.Text;
	using Npgsql;

	GetCatalogItemsSql(null, null, null, 10);

	void GetCatalogItemsSql(int? catalogBrandId, int? before, int? after, int pageSize)
	{
	// This looks like it would be susceptible to SQL injection, but it's not.

davidfowl / SingleThreadedScheduler.cs

Created October 11, 2022 02:53

A sample showing how to schedule work on a single thread

	using System.Collections.Concurrent;
	using System.Threading.Channels;

	var channel = Channel.CreateUnbounded<int>();

	var syncContext = new SingleThreadedSyncContext();

	syncContext.Post(async _ =>
	{
	await foreach (var item in channel.Reader.ReadAllAsync())

davidfowl / DefaultConfigProvider.cs

Last active April 11, 2025 11:04

Allows specifying default configuration values in code while still allowing other sources to override

	using Microsoft.Extensions.Configuration.Memory;

	var builder = WebApplication.CreateBuilder(args);

	builder.Configuration.AddConfigurationDefaults(new()
	{
	{ "request:timeout", "60" }
	});

	var app = builder.Build();

davidfowl / Minimal-protobuf.cs

Last active December 16, 2024 12:58

Minimal + protobuf

	using Microsoft.AspNetCore.Http.Features;
	using Microsoft.AspNetCore.WebUtilities;
	using ProtoBuf;

	var builder = WebApplication.CreateBuilder(args);
	var app = builder.Build();

	app.MapGet("/", () => "POST a protobuf message to the /");
	app.MapPost("/", (Proto<Person> p) => Results.Extensions.Protobuf(p.Item))
	.Accepts<Person>("application/protobuf");

davidfowl / Quic.cs

Last active June 2, 2023 09:16

	using System.IO.Pipelines;
	using System.Net;
	using System.Net.Security;
	using Microsoft.AspNetCore.Connections;
	using Microsoft.AspNetCore.Connections.Features;
	using Microsoft.AspNetCore.Http.Features;
	using Microsoft.AspNetCore.Server.Kestrel.Core;

	var builder = WebApplication.CreateBuilder(args);

davidfowl / DTO.cs

Last active June 2, 2023 09:16

Associated types: A demo of what DTOs could look like as a language feature

	using System.ComponentModel.DataAnnotations;
	using Microsoft.EntityFrameworkCore;

	var builder = WebApplication.CreateBuilder(args);
	var app = builder.Build();

	app.MapPost("/todos", async (CreateTodo createTodo, TodoDb db) =>
	{
	// This is where the implicit conversion comes in
	db.Todos.Add(createTodo);

davidfowl / .NET6Migration.md

Last active April 11, 2025 11:12

.NET 6 ASP.NET Core Migration

Migration to ASP.NET Core in .NET 6

davidfowl / MinimalAPIs.md

Last active March 16, 2025 16:47

Minimal APIs at a glance

This document now exists on the official ASP.NET core docs page.

davidfowl / Example.cs

Last active June 6, 2023 08:10

An implementation of MessagePipe. Something like a channel but with buffer management so you can peek and advance the message that was read.

	using System.Buffers;
	using System.Net.WebSockets;

	var builder = WebApplication.CreateBuilder(args);
	var app = builder.Build();

	app.MapGet("/ws", async (HttpContext context) =>
	{
	const int MaxMessageSize = 1024 * 1024;

davidfowl / server.cs

Last active September 20, 2021 13:56 — forked from DamianEdwards/server.cs

Simplified ASP.NET Core app exploration

	#!/usr/bin/env dotnet run

	var builder = WebApplication.CreateBuilder(args);
	var config = builder.Configuration;
	var connString = config["connectionString"] ?? "Data Source=todos.db";

	builder.AddDbContext<TodoDb>(options => options.UseSqlite(connString));
	builder.AddSqlite<Todo>(connString) // Higher level API perhaps?

	var app = builder.Build();