Initial WebhookServer implementation

Add the .NET 8 solution scaffolded against PLAN.md. Three projects share
WebhookServer.Core (models, auth, execution, storage, IPC, callbacks)
and WebhookServer.Service hosts an embedded Kestrel listener plus the
named-pipe admin server. WebhookServer.Gui is a thin MVVM client over
the pipe. Includes 25 unit tests covering HMAC verification, bearer
auth, IP allowlist parsing, arg-template rendering, DPAPI round-trip,
and the encrypt-on-save config store.

Install/uninstall PowerShell scripts default to LocalSystem and accept
a domain user or gMSA via -ServiceAccount.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-07 22:04:52 -04:00
parent 2f61b342af
commit 8ecfe84540
62 changed files with 3721 additions and 0 deletions
@@ -0,0 +1,116 @@
using System.Text.Json.Nodes;
namespace WebhookServer.Core.Execution;
/// <summary>
/// Resolves {{path}} tokens against an <see cref="ExecutionContext"/>. Each whitespace-
/// separated token in the template becomes one argv entry.
/// Path grammar:
/// {{body.foo.bar}} JSON path into the body
/// {{header.X-Foo}} header by name (case-insensitive)
/// {{query.bar}} query param
/// {{route.slug}} route value
/// Missing paths render as empty string.
/// </summary>
public static class ArgTemplateRenderer
{
public static List<string> Render(string? template, ExecutionContext ctx)
{
var args = new List<string>();
if (string.IsNullOrWhiteSpace(template)) return args;
foreach (var token in template.Split((char[]?)null, StringSplitOptions.RemoveEmptyEntries | StringSplitOptions.TrimEntries))
{
args.Add(RenderToken(token, ctx));
}
return args;
}
private static string RenderToken(string token, ExecutionContext ctx)
{
// Replace every {{...}} occurrence inside the token in a single left-to-right pass.
var result = new System.Text.StringBuilder(token.Length);
var i = 0;
while (i < token.Length)
{
var open = token.IndexOf("{{", i, StringComparison.Ordinal);
if (open < 0)
{
result.Append(token, i, token.Length - i);
break;
}
result.Append(token, i, open - i);
var close = token.IndexOf("}}", open + 2, StringComparison.Ordinal);
if (close < 0)
{
// Unclosed token — treat the rest as literal.
result.Append(token, open, token.Length - open);
break;
}
var path = token.Substring(open + 2, close - (open + 2)).Trim();
result.Append(Resolve(path, ctx));
i = close + 2;
}
return result.ToString();
}
private static string Resolve(string path, ExecutionContext ctx)
{
if (string.IsNullOrEmpty(path)) return "";
var dot = path.IndexOf('.');
if (dot < 0) return "";
var scope = path[..dot];
var rest = path[(dot + 1)..];
return scope.ToLowerInvariant() switch
{
"body" => ResolveJson(ctx.BodyJson, rest),
"header" => LookupCaseInsensitive(ctx.Headers, rest),
"query" => LookupCaseInsensitive(ctx.Query, rest),
"route" => LookupCaseInsensitive(ctx.Route, rest),
_ => "",
};
}
private static string ResolveJson(JsonNode? root, string path)
{
if (root is null) return "";
JsonNode? cursor = root;
foreach (var segment in path.Split('.'))
{
if (cursor is null) return "";
if (cursor is JsonObject obj)
{
cursor = obj.TryGetPropertyValue(segment, out var next) ? next : null;
continue;
}
if (cursor is JsonArray arr && int.TryParse(segment, out var idx))
{
cursor = idx >= 0 && idx < arr.Count ? arr[idx] : null;
continue;
}
return "";
}
return cursor switch
{
null => "",
JsonValue v => v.ToString(),
_ => cursor.ToJsonString(),
};
}
private static string LookupCaseInsensitive(IReadOnlyDictionary<string, string> map, string key)
{
foreach (var kvp in map)
{
if (string.Equals(kvp.Key, key, StringComparison.OrdinalIgnoreCase))
return kvp.Value;
}
return "";
}
}
@@ -0,0 +1,37 @@
using System.Collections.Concurrent;
namespace WebhookServer.Core.Execution;
/// <summary>
/// Holds one <see cref="SemaphoreSlim"/> per endpoint. When an endpoint is configured
/// with Serialize=true, the executor must acquire its semaphore before running and
/// release after — guaranteeing at-most-one concurrent run per endpoint.
/// </summary>
public sealed class ConcurrencyGate
{
private readonly ConcurrentDictionary<Guid, SemaphoreSlim> _gates = new();
public async Task<IDisposable> AcquireAsync(Guid endpointId, CancellationToken ct)
{
var sem = _gates.GetOrAdd(endpointId, _ => new SemaphoreSlim(1, 1));
await sem.WaitAsync(ct).ConfigureAwait(false);
return new Releaser(sem);
}
public void Forget(Guid endpointId)
{
if (_gates.TryRemove(endpointId, out var sem))
sem.Dispose();
}
private sealed class Releaser : IDisposable
{
private SemaphoreSlim? _sem;
public Releaser(SemaphoreSlim sem) => _sem = sem;
public void Dispose()
{
var sem = Interlocked.Exchange(ref _sem, null);
sem?.Release();
}
}
}
@@ -0,0 +1,18 @@
using System.Text.Json.Nodes;
namespace WebhookServer.Core.Execution;
/// <summary>
/// All data the executor needs from the inbound HTTP request.
/// </summary>
public sealed class ExecutionContext
{
public required string RunId { get; init; }
public required string Slug { get; init; }
public required byte[] BodyBytes { get; init; }
public required string BodyString { get; init; }
public JsonNode? BodyJson { get; init; }
public required IReadOnlyDictionary<string, string> Headers { get; init; }
public required IReadOnlyDictionary<string, string> Query { get; init; }
public required IReadOnlyDictionary<string, string> Route { get; init; }
}
@@ -0,0 +1,18 @@
namespace WebhookServer.Core.Execution;
public sealed class ExecutionResult
{
public required string RunId { get; init; }
public required int ExitCode { get; init; }
public required string Stdout { get; init; }
public required string Stderr { get; init; }
public bool StdoutTruncated { get; init; }
public bool StderrTruncated { get; init; }
public required DateTimeOffset StartedAt { get; init; }
public required DateTimeOffset CompletedAt { get; init; }
public required bool TimedOut { get; init; }
public string? LaunchError { get; init; }
public TimeSpan Duration => CompletedAt - StartedAt;
public bool Succeeded => !TimedOut && LaunchError is null && ExitCode == 0;
}
@@ -0,0 +1,8 @@
using WebhookServer.Core.Models;
namespace WebhookServer.Core.Execution;
public interface IExecutor
{
Task<ExecutionResult> RunAsync(EndpointConfig endpoint, ExecutionContext ctx, CancellationToken ct);
}
@@ -0,0 +1,234 @@
using System.Diagnostics;
using System.Text;
using WebhookServer.Core.Models;
namespace WebhookServer.Core.Execution;
public sealed class ProcessExecutor : IExecutor
{
/// <summary>Per-stream cap on captured output (excess is dropped and StdoutTruncated set).</summary>
public const int MaxOutputBytes = 1 * 1024 * 1024;
public async Task<ExecutionResult> RunAsync(EndpointConfig endpoint, ExecutionContext ctx, CancellationToken ct)
{
var startedAt = DateTimeOffset.UtcNow;
var psi = BuildStartInfo(endpoint, ctx);
using var process = new Process { StartInfo = psi, EnableRaisingEvents = true };
try
{
if (!process.Start())
{
return Failed(ctx.RunId, startedAt, "process failed to start");
}
}
catch (Exception ex)
{
return Failed(ctx.RunId, startedAt, $"launch error: {ex.Message}");
}
// stdin
if (endpoint.DataPassing.StdinJson)
{
try
{
if (ctx.BodyBytes.Length > 0)
await process.StandardInput.BaseStream.WriteAsync(ctx.BodyBytes, ct).ConfigureAwait(false);
}
catch (Exception ex)
{
return Failed(ctx.RunId, startedAt, $"stdin write failed: {ex.Message}");
}
finally
{
try { process.StandardInput.Close(); } catch { /* swallow */ }
}
}
else
{
try { process.StandardInput.Close(); } catch { /* swallow */ }
}
// Capture stdout/stderr in parallel, with per-stream cap.
var stdoutTask = ReadCappedAsync(process.StandardOutput, ct);
var stderrTask = ReadCappedAsync(process.StandardError, ct);
var timeout = TimeSpan.FromSeconds(Math.Max(1, endpoint.TimeoutSeconds));
using var timeoutCts = CancellationTokenSource.CreateLinkedTokenSource(ct);
timeoutCts.CancelAfter(timeout);
bool timedOut = false;
try
{
await process.WaitForExitAsync(timeoutCts.Token).ConfigureAwait(false);
}
catch (OperationCanceledException) when (!ct.IsCancellationRequested)
{
timedOut = true;
try { process.Kill(entireProcessTree: true); } catch { /* swallow */ }
try { await process.WaitForExitAsync(CancellationToken.None).ConfigureAwait(false); } catch { /* swallow */ }
}
var (stdout, stdoutTrunc) = await stdoutTask.ConfigureAwait(false);
var (stderr, stderrTrunc) = await stderrTask.ConfigureAwait(false);
return new ExecutionResult
{
RunId = ctx.RunId,
ExitCode = timedOut ? -1 : process.ExitCode,
Stdout = stdout,
Stderr = stderr,
StdoutTruncated = stdoutTrunc,
StderrTruncated = stderrTrunc,
StartedAt = startedAt,
CompletedAt = DateTimeOffset.UtcNow,
TimedOut = timedOut,
};
}
private static ProcessStartInfo BuildStartInfo(EndpointConfig endpoint, ExecutionContext ctx)
{
var psi = new ProcessStartInfo
{
UseShellExecute = false,
CreateNoWindow = true,
RedirectStandardInput = true,
RedirectStandardOutput = true,
RedirectStandardError = true,
WorkingDirectory = string.IsNullOrEmpty(endpoint.WorkingDirectory)
? Environment.CurrentDirectory
: endpoint.WorkingDirectory!,
};
switch (endpoint.ExecutorType)
{
case ExecutorType.WindowsPowerShell:
psi.FileName = "powershell.exe";
AddPwshArgs(psi, endpoint);
break;
case ExecutorType.PwshCore:
psi.FileName = "pwsh.exe";
AddPwshArgs(psi, endpoint);
break;
case ExecutorType.Cmd:
psi.FileName = "cmd.exe";
psi.ArgumentList.Add("/c");
psi.ArgumentList.Add(ResolveCmdInvocation(endpoint));
break;
case ExecutorType.Executable:
psi.FileName = endpoint.ExecutablePath ?? "";
foreach (var staticArg in endpoint.ExecutableArgs)
psi.ArgumentList.Add(staticArg);
break;
default:
throw new ArgumentOutOfRangeException(nameof(endpoint.ExecutorType));
}
if (endpoint.DataPassing.ArgTemplate)
{
foreach (var arg in ArgTemplateRenderer.Render(endpoint.DataPassing.ArgTemplateString, ctx))
psi.ArgumentList.Add(arg);
}
if (endpoint.DataPassing.EnvVars)
{
foreach (var (k, v) in ctx.Headers)
psi.Environment[$"WEBHOOK_HEADER_{Sanitize(k)}"] = v;
foreach (var (k, v) in ctx.Query)
psi.Environment[$"WEBHOOK_QUERY_{Sanitize(k)}"] = v;
}
psi.Environment["WEBHOOK_RUN_ID"] = ctx.RunId;
psi.Environment["WEBHOOK_SLUG"] = ctx.Slug;
return psi;
}
private static void AddPwshArgs(ProcessStartInfo psi, EndpointConfig endpoint)
{
psi.ArgumentList.Add("-NoProfile");
psi.ArgumentList.Add("-NonInteractive");
psi.ArgumentList.Add("-ExecutionPolicy");
psi.ArgumentList.Add("Bypass");
if (!string.IsNullOrEmpty(endpoint.ScriptPath))
{
psi.ArgumentList.Add("-File");
psi.ArgumentList.Add(endpoint.ScriptPath);
}
else
{
psi.ArgumentList.Add("-Command");
psi.ArgumentList.Add(endpoint.InlineCommand ?? "");
}
}
private static string ResolveCmdInvocation(EndpointConfig endpoint)
{
if (!string.IsNullOrEmpty(endpoint.ScriptPath))
return endpoint.ScriptPath!;
return endpoint.InlineCommand ?? "";
}
private static string Sanitize(string key)
{
var sb = new StringBuilder(key.Length);
foreach (var ch in key)
{
if (char.IsLetterOrDigit(ch) || ch == '_')
sb.Append(char.ToUpperInvariant(ch));
else
sb.Append('_');
}
return sb.ToString();
}
private static async Task<(string Text, bool Truncated)> ReadCappedAsync(StreamReader reader, CancellationToken ct)
{
var sb = new StringBuilder();
var buffer = new char[4096];
bool truncated = false;
var byteEstimate = 0;
while (true)
{
int n;
try { n = await reader.ReadAsync(buffer, ct).ConfigureAwait(false); }
catch (OperationCanceledException) { break; }
catch (IOException) { break; }
if (n == 0) break;
// Cheap byte estimate (ASCII-ish); good enough as a guard rail.
if (!truncated)
{
if (byteEstimate + n > MaxOutputBytes)
{
var allowed = MaxOutputBytes - byteEstimate;
if (allowed > 0) sb.Append(buffer, 0, allowed);
truncated = true;
}
else
{
sb.Append(buffer, 0, n);
byteEstimate += n;
}
}
// Else keep draining without storing to keep the pipe from blocking.
}
return (sb.ToString(), truncated);
}
private static ExecutionResult Failed(string runId, DateTimeOffset startedAt, string reason) => new()
{
RunId = runId,
ExitCode = -1,
Stdout = "",
Stderr = "",
StartedAt = startedAt,
CompletedAt = DateTimeOffset.UtcNow,
TimedOut = false,
LaunchError = reason,
};
}