如何使用 JS 抓取 API 上传文件？

javascript fetch-api

2022-08-30 00:17:42

我仍然试图把我的头缠绕在它上面。

我可以让用户选择文件（甚至多个）文件输入：

<form>
  <div>
    <label>Select file to upload</label>
    <input type="file">
  </div>
  <button type="submit">Convert</button>
</form>

我可以使用.但是一旦我这样做了，我如何使用？submit<fill in your event handler here>fetch

fetch('/files', {
  method: 'post',
  // what goes here? What is the "body" for this? content-type header?
}).then(/* whatever */);

答案 1

我是这样做的：

var input = document.querySelector('input[type="file"]')

var data = new FormData()
data.append('file', input.files[0])
data.append('user', 'hubot')

fetch('/avatars', {
  method: 'POST',
  body: data
})

答案 2

这是一个带有注释的基本示例。该函数就是您要查找的功能：upload

// Select your input type file and store it in a variable
const input = document.getElementById('fileinput');

// This will upload the file after having read it
const upload = (file) => {
  fetch('http://www.example.net', { // Your POST endpoint
    method: 'POST',
    headers: {
      // Content-Type may need to be completely **omitted**
      // or you may need something
      "Content-Type": "You will perhaps need to define a content-type here"
    },
    body: file // This is your file object
  }).then(
    response => response.json() // if the response is a JSON object
  ).then(
    success => console.log(success) // Handle the success response object
  ).catch(
    error => console.log(error) // Handle the error response object
  );
};

// Event handler executed when a file is selected
const onSelectFile = () => upload(input.files[0]);

// Add a listener on your input
// It will be triggered when a file will be selected
input.addEventListener('change', onSelectFile, false);