“网络处于脱机状态，Access-Control-Allow-Origin不允许起源，正在卸载页面”，来自Android React Native中的超级代理

Question

我正在使用superagent从我的React Native应用程序上传文件。它在iOS上运行正常，但在Android上却出现此错误：

可能原因：网络离线，Access-Control-Allow-Origin，正在卸载页面，等等。

我在https://snack.expo.io/@twohill/upload-example处创建了一个最小的示例，并复制了以下代码，以防零食消失：

import React, { Component } from 'react';
import { Text, View, StyleSheet, TouchableOpacity } from 'react-native';
import Constants from 'expo-constants';
import * as DocumentPicker from 'expo-document-picker';
import superagent from 'superagent';

import AssetExample from './components/AssetExample';
import { Card } from 'react-native-paper';

const upload = (file, setMessage) => {
  const { name } = file;

  superagent.post('https://example.org/uploads') // <-- change this URL to your server that accepts uploads and is CORS enabled
    .set('Authorization', 'BEARER xxxyyy') // <-- JWT token here
    .attach('uri', file, name)
    .then(
      result => setMessage(JSON.stringify({result})),
      error => setMessage(JSON.stringify({error}))
      );
};

const pickDocuments = async (setMessage) => {
  const file = await DocumentPicker.getDocumentAsync({ copyToCacheDirectory: true });
  if (file.type === "success") {
    upload(file, setMessage);
  }
}

export default class App extends Component {
  state = {
    message: null,
  }
  render() {
    const { message } = this.state;
    return (

      <View style={styles.container}>
       <TouchableOpacity onPress={() => pickDocuments(message => this.setState({message}))}>
        <Text style={styles.paragraph}>
          Tap to upload a file
        </Text>
        <Card>
          <AssetExample />
        </Card>
        <Card><Text>{message}</Text></Card>
         </TouchableOpacity>
      </View>
    );
  }
}

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: 'center',
    paddingTop: Constants.statusBarHeight,
    backgroundColor: '#ecf0f1',
    padding: 8,
  },
  paragraph: {
    margin: 24,
    fontSize: 18,
    fontWeight: 'bold',
    textAlign: 'center',
  },
});

如果出现console.log错误，则会显示以下内容：

Request has been terminated
Possible causes: the network is offline, Origin is not allowed by Access-Control-Allow-Origin, the page is being unloaded, etc.
* http://192.168.1.3:19001/node_modules%5Cexpo%5CAppEntry.bundle?platform=android&dev=true&minify=false&hot=false:282311:24 in crossDomainError
- node_modules\@sentry\utils\dist\instrument.js:224:24 in <anonymous>
- node_modules\event-target-shim\dist\event-target-shim.js:818:39 in EventTarget.prototype.dispatchEvent
- node_modules\react-native\Libraries\Network\XMLHttpRequest.js:566:23 in setReadyState
- node_modules\react-native\Libraries\Network\XMLHttpRequest.js:388:25 in __didCompleteResponse
- node_modules\react-native\Libraries\vendor\emitter\EventEmitter.js:190:12 in emit
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:436:47 in __callFunction
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:111:26 in __guard$argument_0
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:384:10 in __guard
- node_modules\react-native\Libraries\BatchedBridge\MessageQueue.js:110:17 in __guard$argument_0
* [native code]:null in callFunctionReturnFlushedQueue

据我所知，在Android上，该应用从未尝试上传。我的服务器运行express，并启用了cors中间件，并且具有默认配置

{
  "origin": "*",
  "methods": "GET,HEAD,PUT,PATCH,POST,DELETE",
  "preflightContinue": false,
  "optionsSuccessStatus": 204
}

任何想法在这里做什么？我感觉到Android正在“ *”起源，但不知道要为移动应用程序放置什么。

或者我是完全把错误的树吠叫吗？

Answer 1

react-native中的HTTP客户端基本上是带有JS桥的本机HTTP客户端，它没有像Web那样的CORS限制，因此您无需在快速服务器中允许CORS。

就superagent而言，您似乎需要进行一些调整才能在react-native，checkout this issue中使用它>

Answer 2

我认为这可以解决这个问题。