POST in multipart/form-data unexpectedly becomes a GET

[jkomyno]

Versions

• react-native: 0.43.0-rc.4
• react-native-fetch-blob: 0.10.4
• Android 7.1

Background

I have basically copied the structure of the code in the "Multipart/form-data example: Post form data with file and data" section of the README.md.

Use case

I have to download some files (PDFs or images) from a server and display them to the user.
At first I tried with a simple GET request from a local development server, and all went as expected (kudos to you guys!), but when I tried to achieve the same results with a remote API, I got this issue.

I have to use a POST with 'multipart/form-data' for downloading the images, which are dynamically selected according to the form data parameters.

At first, I did't get either a response or an error, so I set up a proxy in my system to intercept the HTTP requests and response in React Native and that's what I got:

So, even though I explicitly set that the request to /euclide/MandocSave should be a POST, react-native-fetch-blob uses a GET instead. Obviously, with a GET you can't have a body in the request, and without that body I can't use the API to obtain what I need.

Snippet

  RNFetchBlob
  .config({
    fileCache: true,
    addAndroidDownloads: {
      useDownloadManager: true,
      notification: false,
      mediaScannable : true,
      description: 'File downloaded by download manager',
    }
  })
  .fetch('POST', 'http://192.168.252.45:9080/euclide/MandocSave', {
    //'Content-Type': 'multipart/form-data',
  },
  [
    {
      name: 'Oper',
      data: 'S',
    }, {
      name: 'procedure',
      data: '*',
    }, {
      name: 'id_company',
      data: '122',
    }, {
      name: 'id_site',
      data: '165',
    }, {
      name: 'attachfilewspace_id',
      data: '853',
    }
  ])
  .progress((received, total) => {
    console.log('progress', received / total)
  })
  .then((res) => {
    console.log('it has responded', res.text());
    android.actionViewIntent(res.path(), 'application/vnd.android.package-archive');
    // RNFetchBlob.android.actionViewIntent(res.path(), 'image/*');
  })
  .catch((err) => {
    console.log('err@RNFetchBlob', err);
  });

Conclusion

How can I achieve my use case? I have already taken a look at the Troubleshooting section without success.
Any help or hint is really appreciated, thanks!

[wkh237]

@jkomyno , thanks for the feedback. I think the problem is that you're using Android's Download Manager as such it becomes a GET request.

From Google's document I don't see anything allow us to change the method or its body.

However, I think if we can't support this one, we should put the extra detail in the document.