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Flutterのjson.decodeの返り値の型が変わったので、それに対応したAPIClientのサンプルコード作りました

2021/06/17に公開

Flutter

Dart

tech

Map<String, dynamic>からdynamicにしれっと変わってて2時間くらい詰まりました。。。

Type aliasesを使えということらしい

import 'dart:convert';
import 'dart:io';

import 'package:http/http.dart' as http;

enum Env {
 local,
 stg,
 production,
}

extension EnvExtension on Env {
 static const _authority = {
   Env.local: 'ローカルのパス',
   Env.stg: 'ステージングのパス',
   Env.production: '本番のパス'
 };

 String get authority => _authority[this]!;
}

typedef Callback = Future<http.Response> Function();
typedef JsonMap = Map<String, dynamic>;
JsonMap parseJsonMap(String input) => json.decode(input) as JsonMap;

class ApiClient {
 factory ApiClient() => _cache;
 ApiClient._internal(this.env);
 static final ApiClient _cache = ApiClient._internal(Env.stg);

 final Env env;

 static const _headers = <String, String>{
   'Content-Type': 'application/json',
 };

 Future<http.Response> _safeApiCall(Callback callback) async {
   try {
     return await callback();
   } on SocketException {
     throw Exception('No Internet Connection');
   }
 }

 Uri _uri(
   String path, {
   Map<String, String>? queryParameters,
 }) {
   final apiPath = '/api$path';
   switch (env) {
     case Env.local:
       return Uri.http(
         env.authority,
         apiPath,
         queryParameters,
       );
     case Env.stg:
     case Env.production:
       return Uri.https(
         env.authority,
         apiPath,
         queryParameters,
       );
   }
 }

 Future<http.Response> get(
   String path, {
   Map<String, String>? queryParameters}) async {
   final url = _uri(path, queryParameters: queryParameters);
   return _safeApiCall(
     () async => http.get(
       url,
       headers: _headers,
     ),
   );
 }

 Future<http.Response> post(String path, {Map<String, String>? body}) async {
   final url = _uri(path);
   return _safeApiCall(
     () async => http.post(
       url,
       headers: _headers,
       body: body,
     ),
   );
 }
}

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