Simple Web Server Sample Code

web-server.dart

import 'dart:io';
import 'dart:convert';
import 'package:http_server/http_server.dart';

class Router {
  void Function(HttpRequest, List<String>, HttpResponse) noRoute;

  Router({this.noRoute = null}) {}

  Map<String, void Function(HttpRequest, List<String>, HttpResponse)> handles =
      {};
  Map<String, RegExp> regex = {};

  bool addRouter(String pattern,
      void Function(HttpRequest, List<String>, HttpResponse) handle) {
    handles[pattern] = handle;
    regex[pattern] = RegExp(pattern);
    return true;
  }

  void serve(HttpRequest req) async {
    for (var i in handles.keys) {
      var r = regex[i];
      var match = r.firstMatch(req.uri.path);
      if (match != null) {
        try {
          await handles[i](
              req,
              match.groups(List.generate(match.groupCount + 1, (i) => i)),
              req.response);
          await req.response.close();
        } catch (e) {
          print(e.toString());
        }

        return;
      }
    }
    if (noRoute != null) {
      noRoute(req, null, req.response);
    } else {
      await req.response.writeln("Route not found.");
      await req.response.close();
    }
  }
}

Future main() async {
  var staticFiles = VirtualDirectory('.');
  staticFiles.allowDirectoryListing = true; /*1*/

  var server;

  try {
    server = await HttpServer.bind(InternetAddress.loopbackIPv4, 4044);
  } catch (e) {
    print("Couldn't bind to port 4044: $e");
    exit(-1);
  }

  var r = Router();
  r
    ..addRouter('cats/', (req, args, resp) {
      resp.writeln(jsonEncode({
        "objs": ["cat1", "cat2", "cat3"]
      }));
    })
    ..addRouter('cat/(\\d)+/', (req, args, resp) {
      resp.writeln(jsonEncode({"name": "cat" + args[1]}));
    })
    ..addRouter('web/.*', (req, args, resp) async {
      await staticFiles.serveRequest(req);
    });
  await for (HttpRequest req in server) {
    r.serve(req);
  }
}