didvan-app/lib/services/network/request.dart

import 'dart:convert';
import 'dart:developer';
import 'dart:io';
import 'package:http/http.dart' as http;

class RequestService {
  static late String _token;

  static set token(value) => _token = value;

  Map get result => _body['result'] ?? const {};
  Map get errors => _body['errors'] ?? const {};

  String errorMessage =
      'خطا! لطفا اتصال اینترنت خود را بررسی و مجددا تلاش نمایید.';

  dynamic _body;
  final Map<String, String> _headers = {
    "accept": "*/*",
    "Content-Type": "application/json; charset=UTF-8",
  };
  final String url;
  dynamic _requestBody;

  bool isSuccess = false;

  RequestService(
    this.url, {
    Map<String, String>? requestHeaders,
    body,
    bool useAutherization = true,
  }) {
    if (body != null) _requestBody = body;
    if (requestHeaders != null) _headers.addAll(requestHeaders);
    if (useAutherization) _headers.addAll({'Authorization': 'Bearer $_token'});
    if (body != null) _requestBody = body;
  }

  Future<void> httpGet() async {
    try {
      final response = await http
          .get(
            Uri.parse(url),
            headers: _headers,
          )
          .timeout(
            const Duration(seconds: 10),
          )
          .catchError(
            (e) => throw e,
          );
      _handleResponse(response);
    } catch (e) {
      _handleError(null);
    }
  }

  Future<void> post() async {
    try {
      final response = await http
          .post(
            Uri.parse(url),
            body: json.encode(_requestBody),
            headers: _headers,
          )
          .timeout(
            const Duration(seconds: 10),
          )
          .catchError(
        (e) {
          throw e;
        },
      );
      _handleResponse(response);
    } catch (e) {
      _handleError(null);
    }
  }

  Future<void> delete() async {
    try {
      final response = await http
          .delete(
            Uri.parse(url),
            body: json.encode(_requestBody),
            headers: _headers,
          )
          .timeout(
            const Duration(seconds: 10),
          )
          .catchError(
            (e) => throw e,
          );
      _handleResponse(response);
    } catch (e) {
      _handleError(null);
    }
  }

  Future<void> multipart(File file) async {
    try {
      final request = http.MultipartRequest('POST', Uri.parse(url));
      _headers.update('Content-Type', (_) => 'multipart/form-data');
      request.headers.addAll(_headers);
      request.files.add(
        http.MultipartFile(
          'file',
          file.readAsBytes().asStream(),
          file.lengthSync(),
          filename: 'desc',
        ),
      );
      final streamedResponse = await request
          .send()
          .timeout(
            const Duration(seconds: 10),
          )
          .catchError(
            (e) => throw e,
          );
      final response = await http.Response.fromStream(streamedResponse);
      _handleResponse(response);
    } catch (e) {
      _handleError(null);
    }
  }

  Future<void> put() async {
    try {
      final response = await http
          .put(
            Uri.parse(url),
            body: json.encode(_requestBody),
            headers: _headers,
          )
          .timeout(
            const Duration(seconds: 10),
          )
          .catchError(
            (e) => throw e,
          );
      _handleResponse(response);
    } catch (e) {
      _handleError(null);
    }
  }

  void _handleResponse(http.Response? response) {
    if (_handleError(response)) {
      if (response!.body.isNotEmpty) {
        _body = json.decode(response.body);
      }
    }
    errorMessage = _errorMessageGenerator(response);
  }

  bool _handleError(http.Response? response) {
    if (response == null) {
      log(
        'Connecion failed or request timedout! ("$url")',
        name: 'Request fail error',
      );
      isSuccess = false;
      return false;
    }
    if (response.statusCode != 200) {
      dynamic data;
      if (response.body.isEmpty) {
        data = 'No results!';
      } else if (response.body.contains('<!DOCTYPE html>')) {
        data = response.body;
      } else {
        data = jsonDecode(response.body);
      }
      log(
        'Request to [$url] failed with status code ${response.statusCode} & result : \n $data',
        name: 'Request fail error',
      );
      isSuccess = false;
      return false;
    }
    isSuccess = true;
    return true;
  }

  String _errorMessageGenerator(http.Response? response) {
    String? error;
    if (response != null) {
      if (!response.body.contains('<!DOCTYPE html>')) {
        if (result.isNotEmpty) {
          error = result['msg'];
        }
      }
    }
    return error ?? 'خطا! لطفا اتصال اینترنت خود را بررسی و مجددا تلاش نمایید.';
  }
}