request formData to API, gets “Network Error” in axios while uploading image

Question

I am making a POST request to server to upload an image and sending formdata using axios in react-native. i am getting "Network Error". i also try fetch but nothing work.using react native image picker libeary for select image.in postman api working fine

        formData.append('title', Title);
        formData.append('class_id', selectClass._id)
        formData.append('subject_id', checkSelected)
        formData.append('teacher_id', userId)
        formData.append('description', lecture);
        formData.append('type', 'image');

       var arr=[];
       arr.push(imageSource)
       arr.map((file,index)=>{
       formData.append('file',{
       uri:file.path,
       type:file.type,
       name:file.name
       })
       })


       axios({
       method: 'post',
       url: URL + 'admin/assignment/create',
       data: data,
       headers: {
       "content-type": "multipart/form-data",
       'x-auth-token': token,
        },
       })
     .then(function (response) {
    //handle success
    console.log('axios assigment post',response);
      })
   .catch(function (response) {
     //handle error
      console.log('axios assigment post',response);
    });

Answer 1

The issue that I was facing which is close to what you are mentioning is that I was getting NetworkError when using image-picker and trying to upload the file using axios. It was working perfectly in iOS but not working in android.

This is how I solved the issue.

There are two independent issues at action here. Let’s say we get imageUri from image-picker, then we would use these following lines of code to upload from the frontend.

const formData = new FormData();
formData.append('image', {
 uri : imageUri,
 type: "image",
 name: imageUri.split("/").pop()
});

The first issue is with the imageUri itself. If let’s say photo path is /user/.../path/to/file.jpg. Then file picker in android would give imageUri value as file:/user/.../path/to/file.jpg whereas file picker in iOS would give imageUri value as file:///user/.../path/to/file.jpg.

The solution for the first issue is to use file:// instead of file: in the formData in android.

The second issue is that we are not using proper mime-type. It is working fine on iOS but not on Android. What makes this worse is that the file-picker package gives the type of the file as “image” and it does not give proper mime-type.

The solution is to use proper mime-type in the formData in the field type. Ex: mime-type for .jpg file would be image/jpeg and for .png file would be image/png. We do not have to do this manually. Instead, you can use a very famous npm package called mime.

The final working solution is:

import mime from "mime";

const newImageUri =  "file:///" + imageUri.split("file:/").join("");

const formData = new FormData();
formData.append('image', {
 uri : newImageUri,
 type: mime.getType(newImageUri),
 name: newImageUri.split("/").pop()
});

I hope this helps to solve your problem :)