React.js, how to send a multipart/form-data to server
The file is also available in the event:
e.target.files[0]
(eliminates the need for document.querySelector('input[type="file"]').files[0];
)
uploadAction(e) {
const data = new FormData();
const imagedata = e.target.files[0];
data.append('inputname', imagedata);
...
Note:
Use console.log(data.get('inputname'))
for debugging, console.log(data)
will not display the appended data.
Here is my solution for image upload with preview through axios.
import React, { Component } from 'react';
import axios from "axios";
React Component Class:
class FileUpload extends Component {
// API Endpoints
custom_file_upload_url = `YOUR_API_ENDPOINT_SHOULD_GOES_HERE`;
constructor(props) {
super(props);
this.state = {
image_file: null,
image_preview: '',
}
}
// Image Preview Handler
handleImagePreview = (e) => {
let image_as_base64 = URL.createObjectURL(e.target.files[0])
let image_as_files = e.target.files[0];
this.setState({
image_preview: image_as_base64,
image_file: image_as_files,
})
}
// Image/File Submit Handler
handleSubmitFile = () => {
if (this.state.image_file !== null){
let formData = new FormData();
formData.append('customFile', this.state.image_file);
// the image field name should be similar to your api endpoint field name
// in my case here the field name is customFile
axios.post(
this.custom_file_upload_url,
formData,
{
headers: {
"Authorization": "YOUR_API_AUTHORIZATION_KEY_SHOULD_GOES_HERE_IF_HAVE",
"Content-type": "multipart/form-data",
},
}
)
.then(res => {
console.log(`Success` + res.data);
})
.catch(err => {
console.log(err);
})
}
}
// render from here
render() {
return (
<div>
{/* image preview */}
<img src={this.state.image_preview} alt="image preview"/>
{/* image input field */}
<input
type="file"
onChange={this.handleImagePreview}
/>
<label>Upload file</label>
<input type="submit" onClick={this.handleSubmitFile} value="Submit"/>
</div>
);
}
}
export default FileUpload;
We just try to remove our headers and it works!
fetch("http://localhost:8910/taskCreationController/createStoryTask", {
mode: 'no-cors',
method: "POST",
body: data
}).then(function (res) {
if (res.ok) {
alert("Perfect! ");
} else if (res.status == 401) {
alert("Oops! ");
}
}, function (e) {
alert("Error submitting form!");
});