Add connection service

lib/db_construction_site.dart

@@ -1,7 +1,12 @@
 library db_construction_site;
 
-/// A Calculator.
-class Calculator {
-  /// Returns [value] plus 1.
-  int addOne(int value) => value + 1;
+import 'package:db_construction_site/services/connection_service.dart';
+
+export 'models/index.dart';
+
+class DBConstructionSite {
+  final ConnectionService connections;
+
+  DBConstructionSite({baseUrl = 'https://bauinfos.deutschebahn.com/app'})
+      : connections = ConnectionService(baseUrl);
 }

lib/models/connection.g.dart

@@ -80,4 +80,5 @@ const _$RegionEnumMap = {
   Region.rhinelandPalatinate: 'rheinland-pfalz',
   Region.hesse: 'hessen',
   Region.northrhineWestphalia: 'nrw',
+  Region.longDistance: 'fernverkehr',
 };

lib/models/connection_type_converter.dart

@@ -0,0 +1,15 @@
+import 'package:json_annotation/json_annotation.dart';
+
+import 'connection_type.dart';
+
+part 'connection_type_converter.g.dart';
+
+@JsonSerializable(createFactory: false)
+class ConnectionTypeConverter {
+  final ConnectionType type;
+
+  const ConnectionTypeConverter(this.type);
+
+  @JsonKey(ignore: true)
+  String get value => _$ConnectionTypeConverterToJson(this)["type"];
+}

lib/models/connection_type_converter.g.dart

@@ -0,0 +1,19 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'connection_type_converter.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+Map<String, dynamic> _$ConnectionTypeConverterToJson(
+        ConnectionTypeConverter instance) =>
+    <String, dynamic>{
+      'type': _$ConnectionTypeEnumMap[instance.type],
+    };
+
+const _$ConnectionTypeEnumMap = {
+  ConnectionType.longDistance: 'fern',
+  ConnectionType.regional: 'regional',
+  ConnectionType.sBahn: 'sbahn',
+};

lib/models/index.dart

@@ -0,0 +1,3 @@
+export 'connection.dart';
+export 'region.dart';
+export 'connection_type.dart';

lib/models/region.dart

@@ -47,5 +47,9 @@ enum Region {
 
   /// Northrhine-Westphalia
   @JsonValue("nrw")
-  northrhineWestphalia
+  northrhineWestphalia,
+
+  /// Long distance trains with multiple regions
+  @JsonValue("fernverkehr")
+  longDistance,
 }

lib/models/region_converter.dart

@@ -0,0 +1,15 @@
+import 'package:json_annotation/json_annotation.dart';
+
+import 'region.dart';
+
+part 'region_converter.g.dart';
+
+@JsonSerializable(createFactory: false)
+class RegionConverter {
+  final Region region;
+
+  const RegionConverter(this.region);
+
+  @JsonKey(ignore: true)
+  String get value => _$RegionConverterToJson(this)["region"];
+}

lib/models/region_converter.g.dart

@@ -0,0 +1,28 @@
+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'region_converter.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+Map<String, dynamic> _$RegionConverterToJson(RegionConverter instance) =>
+    <String, dynamic>{
+      'region': _$RegionEnumMap[instance.region],
+    };
+
+const _$RegionEnumMap = {
+  Region.lowerSaxonyBremen: 'niedersachen-bremen',
+  Region.north: 'norden',
+  Region.mecklenburgWesternPomerania: 'mvp',
+  Region.berlinBrandenburg: 'berlin-bb',
+  Region.saxonyAnhalt: 'sachsen-anhalt',
+  Region.saxony: 'sachsen',
+  Region.bavaria: 'bayern',
+  Region.thuringia: 'thueringen',
+  Region.badenWuerttemberg: 'baden-w',
+  Region.rhinelandPalatinate: 'rheinland-pfalz',
+  Region.hesse: 'hessen',
+  Region.northrhineWestphalia: 'nrw',
+  Region.longDistance: 'fernverkehr',
+};

lib/services/connection_service.dart

@@ -0,0 +1,34 @@
+import 'dart:convert';
+import 'dart:io';
+
+import 'package:db_construction_site/models/connection.dart';
+import 'package:db_construction_site/models/connection_type.dart';
+import 'package:db_construction_site/models/connection_type_converter.dart';
+import 'package:db_construction_site/models/region.dart';
+import 'package:db_construction_site/models/region_converter.dart';
+import 'package:http/http.dart' as http;
+
+class ConnectionService {
+  final String baseUrl;
+
+  const ConnectionService(this.baseUrl);
+
+  Future<List<Connection>> findConnections(Region region,
+      {ConnectionType connectionType}) async {
+    final regionValue = RegionConverter(region).value;
+    var url = '$baseUrl/list/${regionValue}';
+    if (connectionType != null) {
+      final connectionTypeValue = ConnectionTypeConverter(connectionType).value;
+      url += ',${connectionTypeValue}';
+    }
+    final result = await http.get(url);
+    if (result.statusCode ~/ 100 != 2) {
+      throw HttpException("unexpected status code ${result.statusCode}",
+          uri: result.request.url);
+    }
+    final List<dynamic> connections = JsonDecoder().convert(result.body);
+    return connections
+        .map((connection) => Connection.fromJson(connection))
+        .toList();
+  }
+}

test/db_construction_site_test.dart

@@ -3,11 +3,20 @@ import 'package:test/test.dart';
 import 'package:db_construction_site/db_construction_site.dart';
 
 void main() {
-  test('adds one to input values', () {
-    final calculator = Calculator();
-    expect(calculator.addOne(2), 3);
-    expect(calculator.addOne(-7), -6);
-    expect(calculator.addOne(0), 1);
-    expect(() => calculator.addOne(null), throwsNoSuchMethodError);
+  test('check if example request succeeds', () async {
+    final connections =
+        await DBConstructionSite().connections.findConnections(Region.hesse);
+    expect(connections.length, greaterThan(0));
+  });
+
+  test('check if invalid request fails', () async {
+    try {
+      await DBConstructionSite(baseUrl: 'https://noanurl.local')
+          .connections
+          .findConnections(Region.hesse);
+      fail("Request succeeds although it should fail");
+    } catch (e) {
+      // success
+    }
   });
 }

test/models/connection_test.dart

@@ -1,8 +1,6 @@
 import 'dart:convert';
 
-import 'package:db_construction_site/models/connection.dart';
-import 'package:db_construction_site/models/connection_type.dart';
-import 'package:db_construction_site/models/region.dart';
+import 'package:db_construction_site/db_construction_site.dart';
 import 'package:test/test.dart';
 
 void main() {
@@ -56,4 +54,4 @@ void main() {
     expect(connection.type, ConnectionType.regional);
     expect(connection.region, Region.hesse);
   });
-}
+}