多部分的主体

将数据发送为 multipart/form-data

¥Posting data as multipart/form-data

使用表单数据 API

¥Using FormData API

浏览器

¥Browser

const form = new FormData();
form.append('my_field', 'my value');
form.append('my_buffer', new Blob([1,2,3]));
form.append('my_file', fileInput.files[0]);

axios.post('https://example.com', form)

使用内部 Axios 序列化器和相应的速记方法可以实现相同的结果：

¥The same result can be achieved using the internal Axios serializer and corresponding shorthand method:

axios.postForm('https://httpbin.org/post', {
  my_field: 'my value',
  my_buffer: new Blob([1,2,3]),
  my_file:  fileInput.files // FileList will be unwrapped as sepate fields
});

HTML 表单可以直接作为请求负载传递

¥HTML form can be passed directly as a request payload

Node.js

import axios from 'axios';

const form = new FormData();
form.append('my_field', 'my value');
form.append('my_buffer', new Blob(['some content']));

axios.post('https://example.com', form)

由于 node.js 当前不支持从文件创建 Blob，因此你可以使用第三方包来实现此目的。

¥Since node.js does not currently support creating a Blob from a file, you can use a third-party package for this purpose.

import {fileFromPath} from 'formdata-node/file-from-path'

form.append('my_field', 'my value');
form.append('my_file', await fileFromPath('/foo/bar.jpg'));

axios.post('https://example.com', form)

对于早于 v1.3.0 的 Axios，你必须导入 form-data 包。

¥For Axios older than v1.3.0 you must import form-data package.

const FormData = require('form-data');

const form = new FormData();
form.append('my_field', 'my value');
form.append('my_buffer', new Buffer(10));
form.append('my_file', fs.createReadStream('/foo/bar.jpg'));

axios.post('https://example.com', form)

🆕 自动序列化

¥🆕 Automatic serialization

从 v0.27.0 开始，如果请求 Content-Type 标头设置为 multipart/form-data，axios 支持自动将对象序列化为 FormData 对象。

¥Starting from v0.27.0, Axios supports automatic object serialization to a FormData object if the request Content-Type header is set to multipart/form-data.

以下请求将以 FormData 格式（浏览器和 Node.js）提交数据：

¥The following request will submit the data in a FormData format (Browser & Node.js):

import axios from 'axios';

axios.post('https://httpbin.org/post', {
  user: {
    name: 'Dmitriy'
  },
  file: fs.createReadStream('/foo/bar.jpg')
}, {
  headers: {
    'Content-Type': 'multipart/form-data'
  }
}).then(({data})=> console.log(data));

Axios FormData 序列化器支持一些特殊的结尾来执行以下操作：

¥Axios FormData serializer supports some special endings to perform the following operations:

• {} - 使用 JSON.stringify 序列化值

  ¥{} - serialize the value with JSON.stringify

• [] - 将类似数组的对象解包为具有相同键的单独字段

  ¥[] - unwrap the array-like object as separate fields with the same key

注意：解包/展开操作将默认用于数组和 FileList 对象

¥NOTE: unwrap/expand operation will be used by default on arrays and FileList objects

FormData 序列化器通过 config.formSerializer: object 属性支持额外的选项来处理罕见的情况：

¥FormData serializer supports additional options via config.formSerializer: object property to handle rare cases:

• visitor: Function - 用户定义的访问者函数，将按照自定义规则递归调用以将数据对象序列化为 FormData 对象。

  ¥visitor: Function - user-defined visitor function that will be called recursively to serialize the data object to a FormData object by following custom rules.

• dots: boolean = false - 使用点符号而不是括号来序列化数组和对象；

  ¥dots: boolean = false - use dot notation instead of brackets to serialize arrays and objects;

• metaTokens: boolean = true - 在 FormData 键中添加特殊结尾（例如 user{}: '{"name": "John"}'）。后端主体解析器可能会使用此元信息自动将值解析为 JSON。

  ¥metaTokens: boolean = true - add the special ending (e.g user{}: '{"name": "John"}') in the FormData key. The back-end body-parser could potentially use this meta-information to automatically parse the value as JSON.

• indexes: null|false|true = false - 控制如何将索引添加到 flat 类数组对象的展开键

  ¥indexes: null|false|true = false - controls how indexes will be added to unwrapped keys of flat array-like objects

  • null - 不要添加括号 (arr: 1, arr: 2, arr: 3)

    ¥null - don't add brackets (arr: 1, arr: 2, arr: 3)

  • false(default) - 添加空括号（arr[]: 1、arr[]: 2、arr[]: 3）

    ¥false(default) - add empty brackets (arr[]: 1, arr[]: 2, arr[]: 3)

  • true - 添加带有索引的括号（arr[0]: 1、arr[1]: 2、arr[2]: 3）

    ¥true - add brackets with indexes (arr[0]: 1, arr[1]: 2, arr[2]: 3)

假设我们有这样一个对象：

¥Let's say we have an object like this one:

const obj = {
  x: 1,
  arr: [1, 2, 3],
  arr2: [1, [2], 3],
  users: [{name: 'Peter', surname: 'Griffin'}, {name: 'Thomas', surname: 'Anderson'}],
  'obj2{}': [{x:1}]
};

以下步骤将由 Axios 序列化器在内部执行：

¥The following steps will be executed by the Axios serializer internally:

const formData= new FormData();
formData.append('x', '1');
formData.append('arr[]', '1');
formData.append('arr[]', '2');
formData.append('arr[]', '3');
formData.append('arr2[0]', '1');
formData.append('arr2[1][0]', '2');
formData.append('arr2[2]', '3');
formData.append('users[0][name]', 'Peter');
formData.append('users[0][surname]', 'Griffin');
formData.append('users[1][name]', 'Thomas');
formData.append('users[1][surname]', 'Anderson');
formData.append('obj2{}', '[{"x":1}]');

import axios from 'axios';

axios.post('https://httpbin.org/post', {
  'myObj{}': {x: 1, s: "foo"},
  'files[]': document.querySelector('#fileInput').files 
}, {
  headers: {
    'Content-Type': 'multipart/form-data'
  }
}).then(({data})=> console.log(data));

axios 支持以下快捷方法：postForm、putForm、patchForm 就是对应的 HTTP 方法，content-type 标头预设为 multipart/form-data。

¥Axios supports the following shortcut methods: postForm, putForm, patchForm which are just the corresponding http methods with the content-type header preset to multipart/form-data.

FileList 对象可以直接传递：

¥FileList object can be passed directly:

await axios.postForm('https://httpbin.org/post', document.querySelector('#fileInput').files)

所有文件都将使用相同的字段名称发送：files[]；

¥All files will be sent with the same field names: files[];