Flutter GraphQL请求拦截HTTP状态码插件graphql_intercept_http_code_link的使用

本文将介绍如何在Flutter项目中使用graphql_intercept_http_code_link插件来拦截GraphQL请求中的HTTP状态码。通过此插件，您可以捕获并处理来自GraphQL服务器的HTTP响应状态码。

Getting Started（开始使用）

graphql_intercept_http_code_link是一个用于拦截GraphQL HTTP状态码的Flutter插件。它可以帮助您在GraphQL请求失败时根据不同的HTTP状态码执行相应的操作。

安装插件

首先，在您的pubspec.yaml文件中添加以下依赖：

dependencies:
  graphql_flutter: ^5.0.0
  graphql_intercept_http_code_link: ^1.0.0

然后运行flutter pub get以安装依赖。

配置插件

接下来，我们将配置graphql_intercept_http_code_link插件并将其与GraphQLClient集成。

示例代码

以下是一个完整的示例代码，展示如何使用graphql_intercept_http_code_link插件来拦截HTTP状态码。

import 'package:flutter/material.dart';
import 'package:graphql_flutter/graphql_flutter.dart';
import 'package:graphql_intercept_http_code_link/graphql_intercept_http_code_link.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  [@override](/user/override)
  Widget build(BuildContext context) {
    return MaterialApp(
      home: GraphQLInterceptExample(),
    );
  }
}

class GraphQLInterceptExample extends StatefulWidget {
  [@override](/user/override)
  _GraphQLInterceptExampleState createState() => _GraphQLInterceptExampleState();
}

class _GraphQLInterceptExampleState extends State<GraphQLInterceptExample> {
  late GraphQLClient _client;

  [@override](/user/override)
  void initState() {
    super.initState();

    // 创建一个GraphQL链接，并添加拦截器
    final HttpLink httpLink = HttpLink('https://your-graphql-endpoint.com/graphql');
    final Link link = ApolloLink.from([
      GraphQLInterceptorHttpCodeLink(
        onHttpError: (response, error) {
          print('HTTP Error: ${error.statusCode}');
          if (error.statusCode == 401) {
            // 处理401 Unauthorized错误
            print('Unauthorized access. Please log in again.');
          } else if (error.statusCode == 500) {
            // 处理500 Internal Server Error错误
            print('Server error occurred.');
          }
        },
      ),
      httpLink,
    ]);

    // 创建GraphQL客户端
    _client = GraphQLClient(
      cache: InMemoryCache(),
      link: link,
    );
  }

  Future<void> _fetchData() async {
    final QueryOptions options = QueryOptions(
      document: gql("""
        query {
          user {
            id
            name
          }
        }
      """),
    );

    try {
      final QueryResult result = await _client.query(options);
      if (result.hasException) {
        print('Query Exception: ${result.exception}');
      } else {
        print('Query Result: ${result.data}');
      }
    } catch (e) {
      print('Error fetching data: $e');
    }
  }

  [@override](/user/override)
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('GraphQL Interceptor Example'),
      ),
      body: Center(
        child: ElevatedButton(
          onPressed: _fetchData,
          child: Text('Fetch Data'),
        ),
      ),
    );
  }
}