horse-provider-mormot

mORMot2 transport provider for the Horse web framework. Replaces Indy's blocking-thread-per-connection model with mORMot2's HTTP server stack — kernel-level async I/O (IOCP on Windows, epoll on Linux). Three interchangeable backends selectable via THorseMormotConfig.ServerKind: THttpServer (thread-pool, default), THttpAsyncServer (non-blocking event loop), and THttpApiServer (Windows http.sys kernel-mode) — see Server backend. Hybrid-interface architecture (IHorseRawRequest / IHorseRawResponse) so every Horse middleware works unchanged.

Status

🚧 Under construction. This repo is a scaffold. Implementation follows the blueprint at horse-provider-mormot/doc/building-a-mormot-provider.md — read that first.

Activation

{$DEFINE HORSE_PROVIDER_MORMOT}   // canonical (PATCH-HORSE-2 namespace)

uses
  Horse;

begin
  THorse.Get('/ping', procedure (Req: THorseRequest; Res: THorseResponse)
  begin
    Res.Send('pong');
  end);
  THorse.Listen(9000);
end.

HORSE_PROVIDER_MORMOT is reserved in patches/horse/src/Horse.pas (PATCH-HORSE-2 three-axis define model). No legacy alias.

Server backend — thread-pool / async / http.sys

The provider can host any of mORMot2's HTTP servers. All share the same request handler, so routing, middleware, the context pool and the request/response bridge are identical — only the server engine differs:

ServerKind	mORMot class	Model	Platform
mskThreadPool (default)	THttpServer	Socket thread-pool — one thread per concurrent request	All
mskAsync	THttpAsyncServer	Non-blocking event loop (IOCP / epoll / kqueue) — scales past thread-per-request	All
mskHttpApi	THttpApiServer	Windows http.sys kernel-mode HTTP — port-sharing, URL ACLs	Windows only

mskThreadPool/mskAsync descend from THttpServerSocketGeneric; mskHttpApi descends from THttpServerGeneric and is built differently (the provider calls AddUrl to register http://+:<port>/). Selecting mskHttpApi on a non-Windows build raises at Listen.

http.sys URL registration. mskHttpApi registers the listening prefix with http.sys, which needs Administrator rights, or a one-time per-port reservation: netsh http add urlacl url=http://+:<port>/ user=<account>. If registration fails the provider raises at Listen with this exact remedy in the message (it never binds silently).

Default: with no config and no define, the provider uses mskThreadPool (THttpServer) — unchanged from earlier releases. Two ways to switch backend (async shown; mskHttpApi is identical):

// 1. Runtime (preferred) — explicit, no build-config dependency:
var
  Cfg: THorseMormotConfig;
begin
  Cfg := THorseMormotConfig.Default;
  Cfg.ServerKind := mskAsync;          // → THttpAsyncServer
  THorse.ListenWithConfig(9000, Cfg);
end;

// 2. Compile-time default — a provider-internal option define, set PROJECT-WIDE
//    (Delphi: Project ▸ Options ▸ Conditional defines; FPC/Lazarus: -dHORSE_MORMOT_ASYNC).
//    A bare {$DEFINE} in the .dpr/.lpr is NOT seen by the Config unit.
{$DEFINE HORSE_MORMOT_ASYNC}           // sibling of HORSE_MORMOT_TRACE
// then a plain THorse.Listen(9000); uses THttpAsyncServer by default.

ThreadPool changes meaning in async mode. For mskThreadPool it is the number of concurrent request slots; for mskAsync it sizes the async R/W event-loop threads (think CPU cores, not client count). An explicit ServerKind on the config always wins over the define.

Mental model (mirrors the define tiers in Horse.pas):

HORSE_PROVIDER_MORMOT      ← selects the mORMot transport (axis A)
  HORSE_MORMOT_ASYNC       ← option: use THttpAsyncServer instead of THttpServer
  HORSE_MORMOT_HTTPAPI     ← option (Windows): use http.sys THttpApiServer
  HORSE_MORMOT_TRACE       ← option: emit lifecycle trace

Define precedence in THorseMormotConfig.Default: HORSE_MORMOT_HTTPAPI (Windows) → HORSE_MORMOT_ASYNC → thread-pool. A runtime Cfg.ServerKind always overrides the define.

Minimum requirements

Component	Minimum	Notes
Delphi	10.4 Sydney	inline var, System.Threading — same baseline as Horse.
Lazarus / FPC	3.2.0	Unlike the CrossSocket provider (which needs FPC 3.3.1 trunk for {$MODESWITCH FUNCTIONREFERENCES}), mORMot2 has no such requirement. FPC 3.2.2 stable + Lazarus 2.2+ work out of the box. See Lazarus / FPC IDE setup below.
mORMot2	latest	Core units: mormot.core.base, mormot.core.unicode, mormot.net.http, mormot.net.server.
Horse	≥ 3.1.98	The PATCH-HORSE-2 release — older versions lack the HORSE_PROVIDER_* namespace.
OpenSSL	1.1.x or 3.x	Only if HTTPS is enabled.

mORMot2 static blobs

Static-blob folder required on every target — download mormot2static.7z from the latest mORMot2 GitHub release (or https://synopse.info/files/mormot2static.7z) and extract into mORMot2/static/:

Build target	Static path
Delphi / Windows	mORMot2\static\delphi — precompiled .obj files
Delphi / Linux64	mORMot2/static/delphi-linux64 — precompiled .o files
FPC (any platform)	Add -Fl<path> pointing at mORMot2/static/$(TargetCPU)-$(TargetOS) — e.g. static/x86_64-win64, static/x86_64-linux, static/aarch64-linux

See samples/tests/README.md → "Building each project" for the full search-path list with absolute paths.

OpenSSL (only if HTTPS is enabled)

mORMot2 dynamically loads libssl / libcrypto at startup, OR statically links via the mormot2static bundle (preferred for self-contained deployments). Both 1.1.x and 3.x ABIs are accepted.

• Linux dynamic: apt install libssl3 libcrypto3 (Debian/Ubuntu 22.04+, RHEL 9+) or libssl1.1 (Ubuntu 20.04).
• Windows dynamic: ship libssl-3-x64.dll + libcrypto-3-x64.dll (or the 1.1.x equivalents) next to the .exe — not in System32.
• Static link: preferred for Docker / air-gapped — use the OpenSSL .o/.obj shipped inside mormot2static and reference them via the same search-path that brings in zlib/sqlite.

Lazarus / FPC IDE setup

Key difference from the CrossSocket provider: mORMot2 supports FPC 3.2.0+ and does not need FPC 3.3.1 trunk. FPC 3.2.2 stable (Lazarus 2.2+) is sufficient.

1. mormot2 package — open mORMot2/src/packages/lazarus/mormot2.lpk in the Lazarus IDE, compile it. Installation is only needed for design-time components; the HTTP server works with Compile only.

2. LazUtils package — add LazUtils to your project's required packages (Project → Project Inspector → Required Packages → Add → LazUtils). mORMot2's Lazarus package lists LazUtils as a dependency; omitting it causes a "Cannot find Masks" or similar compile error.

3. Source search paths — add to Project Options → Compiler Options → Paths → Other unit files (-Fu):

   <mORMot2>/src
   <mORMot2>/src/core
   <mORMot2>/src/net
   <mORMot2>/src/lib
   <horse>/src
   <horse-provider-mormot>/src
   

4. Static blob linker path — add to Other linker options (-Fl):

   <mORMot2>/static/$(TargetCPU)-$(TargetOS)
   

   On a 64-bit Windows FPC build this resolves to static/x86_64-win64; on Linux to static/x86_64-linux.

5. Project define — add -dHORSE_PROVIDER_MORMOT to Project Options → Compiler Options → Custom options.

Anonymous procedures in FPC middleware: FPC 3.2+ in {$MODE DELPHI} supports anonymous procedures. The third parameter of a Horse middleware callback must be typed as TNextProc (not TProc) — the two are distinct types on FPC (TNextProc = procedure of object; TProc = procedure). Always write:

THorse.Use(procedure(Req: THorseRequest; Res: THorseResponse; Next: TNextProc)
  begin ... Next; end);

Layout

src/
├── Horse.Provider.Mormot.pas              Entry point — owns the server (THttpServer/THttpAsyncServer), ExecutePipeline, SendError
├── Horse.Provider.Mormot.Config.pas       THorseMormotConfig record (ServerKind, ThreadPool, MaxBodyBytes, …)
├── Horse.Provider.Mormot.Pool.pas         Pre-allocated THorseContext pool
├── Horse.Provider.Mormot.Request.pas      TMormotRequestBridge — Validate + Populate
├── Horse.Provider.Mormot.Response.pas     TMormotResponseBridge.Flush
├── Horse.Provider.Mormot.RawRequest.pas   TMormotRawRequest implements IHorseRawRequest
├── Horse.Provider.Mormot.RawResponse.pas  TMormotRawResponse implements IHorseRawResponse
├── Horse.Provider.Mormot.WebRequestAdapter.pas   TMormotWebRequest  (thin subclass)
├── Horse.Provider.Mormot.WebResponseAdapter.pas  TMormotWebResponse (thin subclass)
├── Horse.Provider.Mormot.VCL.pas                  TfrmHorseMormotVCLHost + Delphi VCL marker
├── Horse.Provider.Mormot.Daemon.pas               Delphi cross-platform daemon (Windows TService / POSIX signals)
├── Horse.Provider.Mormot.FPC.Daemon.pas           FPC Linux daemon (fpSignal handlers)
├── Horse.Provider.Mormot.FPC.LCL.pas              Lazarus LCL host form
└── Horse.Provider.Mormot.FPC.HTTPApplication.pas  FPC HTTPApplication-style runner

samples/
├── Delphi/console/                         Single-route console demo
└── tests/                                  Integration test server (HorseMormotTestServer.dpr)

License

MIT.