React Native fetch() Network Request Failed

fixed TypeError: Network request failed when upload file to http not https with Android debug builds

In react-native 0.63.2 (I’m testing) or some higher version, if just use fetch to upload file to a http (not https) server, will meet TypeError: Network request failed.

Here I use [email protected] as client running on an Android phone successfully upload a file to react-native-file-server as server running on another Android phone.

client need edit JAVA and JS code, server no need edit JAVA code.

With debug builds, must commenting out line number 43 in this file android/app/src/debug/java/com/YOUR_PACKAGE_NAME/ReactNativeFlipper.java

38      NetworkFlipperPlugin networkFlipperPlugin = new NetworkFlipperPlugin();
39      NetworkingModule.setCustomClientBuilder(
40          new NetworkingModule.CustomClientBuilder() {
41            @Override
42            public void apply(OkHttpClient.Builder builder) {
43      //        builder.addNetworkInterceptor(new FlipperOkhttpInterceptor(networkFlipperPlugin));
44            }
45          });
46      client.addPlugin(networkFlipperPlugin);

Maybe also need add android:usesCleartextTraffic="true" under <application of android/app/src/main/AndroidManifest.xml , on my test, it’s not necessary on both debug and release builds.

  onFileSelected = async (file) => {
    // API ref to the server side BE code `addWebServerFilter("/api/uploadtodir", new WebServerFilter()`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L356
    // could not be 'localhost' but IP address
    const serverUploadApi = 'http://192.168.1.123:8080/api/uploadtodir';

    // the folder on server where file will be uploaded to, could be e.g. '/storage/emulated/0/Download'
    const serverFolder = '/storage/emulated/0/FileServerUpload';

    const fileToUpload = {
      // if want to upload and rename, it can be `name: 'foo.bar'`, but can not be 'foo'
      // only if your server upload code support file name without type, on our server
      // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L372
      // will cause java.lang.StringIndexOutOfBoundsException in substring()
      name: file.name,

      // type is necessary in Android, it can be 'image/jpeg' or 'foo/bar', but can not be
      // 'foo', 'foo/', '/foo' or undefined, otherwise will cause `[AxiosError: Network Error]`
      type: 'a/b',

      uri: Platform.OS === 'android' ? file.uri : file.uri.replace('file://', ''),
    };

    const form = new FormData();
    form.append('path', serverFolder);
    form.append('uploadfile', fileToUpload);

    // ref to the server side FE code `this.axios.post("/api/uploadtodir", parms, config)`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/fileserverwebdoc/src/views/Manage.vue#L411
    let res = await axios.post(serverUploadApi, form, {
      headers: {
        'Content-Type': 'multipart/form-data',
      },
      onUploadProgress: function (progressEvent) {
        console.warn(progressEvent);
      },
    });

    // ref to the server side BE code `return newFixedLengthResponse("Suss");`
    // https://github.com/flyskywhy/react-native-file-server/blob/1034a33dd6d8b0999705927ad78368ca1a639add/android/src/main/java/webserver/WebServer.java#L380
    if (res.data === 'Suss') {
      console.warn('Upload Successful');
    } else if (res.data === 'fail') {
      console.warn('Upload Failed');
    }
  };