Overview

libmicrohttpd wraps GNU libmicrohttpd — a small C library that lets you embed a full HTTP/1.1 server inside any program. No separate server process required; the listener runs in your PascalAI application alongside your agents and business logic.

It handles the full HTTP protocol: persistent connections, chunked transfer encoding, pipelining, TLS via GnuTLS, and POST body parsing for both form-urlencoded and multipart data. Three threading models cover everything from single-threaded embedded devices to high-concurrency API servers.

Key Features

Thread Modes

Comparison

Quick Start

Minimal REST API server (GET /hello, POST /echo)

uses libmicrohttpd;

var d := Start(8080, mmThreadPerConn);
WriteLn('Listening on http://localhost:8080');

var req: TMHDRequest;
var conn: TMHDConn;

while WaitRequest(d, 5000, req, conn) do
begin
  if (req.Method = 'GET') and (req.Path = '/hello') then
    SendJSON(conn, 200, '{"message":"Hello, world!"}')

  else if (req.Method = 'POST') and (req.Path = '/echo') then
    SendJSON(conn, 200, req.Body)   { echo the raw body back }

  else
    NotFound(conn);
end;

Stop(d);

JSON API with Basic auth and thread pool

uses libmicrohttpd;

const
  API_USER = 'admin';
  API_PASS = 's3cr3t';

var d := StartPool(8443, 4);   { 4-thread pool on port 8443 }
WriteLn('API server on :8443 (4 threads)');

var req: TMHDRequest;
var conn: TMHDConn;

while WaitRequest(d, -1, req, conn) do
begin
  { Guard all routes with Basic auth }
  if not CheckBasicAuth(conn, API_USER, API_PASS) then
  begin
    ChallengeBasicAuth(conn, 'My API');
    continue;
  end;

  if req.Path = '/api/status' then
  begin
    var active := ActiveConnections(d);
    SendJSON(conn, 200,
      '{"status":"ok","connections":' + IntToStr(active) + '}');
  end

  else if req.Path = '/api/files' then
  begin
    var resp := NewFileResponse('/var/www/index.html');
    SetContentType(resp, 'text/html; charset=utf-8');
    SendResponse(conn, 200, resp);
  end

  else
    NotFound(conn);
end;

Stop(d);

Types

Server Lifecycle

Request Handling

Response Building

Build a response object, optionally attach headers, then send it with SendResponse. The library destroys the response after sending.

Convenience Helpers

One-liner helpers that create, configure, and send a response in a single call.

POST Body

Use the POST processor API for form submissions and file uploads. Feed body data incrementally as it arrives, then extract named fields.

uses libmicrohttpd;

{ Handle a form POST to /submit }
var req: TMHDRequest;
var conn: TMHDConn;
var d := Start(8080, mmSelectInternally);

while WaitRequest(d, -1, req, conn) do
begin
  if (req.Method = 'POST') and (req.Path = '/submit') then
  begin
    var pp := NewPostProc(conn);
    PostProcFeed(pp, req.Body);
    var name  := GetPostField(pp, 'name');
    var email := GetPostField(pp, 'email');
    FreePostProc(pp);
    SendJSON(conn, 200, '{"ok":true,"name":"' + name + '"}');
  end
  else
    NotFound(conn);
end;

Stop(d);

Authentication

Info