如何在请求node-fetch或nodejs中发送文件

Question

如何在nodejs/node-fetch POST请求中附加文件.我想调用导入文件的API(.xls或csv).如何使用Node-fetch/nodejs执行此操作.

Answer 1

我一直在寻找如何使用node-fetch通过上传文件multipart/form-data，他们的 GitHub 文档实际上展示了如何做到这一点。下面是修改后的示例，显示了如何将缓冲区附加到FormData并上传它。

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

const buffer = // e.g. `fs.readFileSync('./fileLocation');
const fileName = 'test.txt';

form.append('file', buffer, {
  contentType: 'text/plain',
  name: 'file',
  filename: fileName,
});

fetch('https://httpbin.org/post', { method: 'POST', body: form })
    .then(res => res.json())
    .then(json => console.log(json));

与像我一样在谷歌上搜索“node-fetch upload file multipart”的其他人分享这个。

Answer 2

README.md 说:

在请求和响应上使用本机流作为正文.

而消息来源表明它支持多种类型,比如Stream,Buffer,Blob...也将试着将其转换为String其他类型.

下面的代码段显示了3个示例,所有工作都在使用v1.7.1或2.0.0-alpha5(另请参见下面的其他示例FormData):

let fetch = require('node-fetch');
let fs = require('fs');

const stats = fs.statSync("foo.txt");
const fileSizeInBytes = stats.size;

// You can pass any of the 3 objects below as body
let readStream = fs.createReadStream('foo.txt');
//var stringContent = fs.readFileSync('foo.txt', 'utf8');
//var bufferContent = fs.readFileSync('foo.txt');

fetch('http://httpbin.org/post', {
    method: 'POST',
    headers: {
        "Content-length": fileSizeInBytes
    },
    body: readStream // Here, stringContent or bufferContent would also work
})
.then(function(res) {
    return res.json();
}).then(function(json) {
    console.log(json);
});

这是foo.txt:

hello world!
how do you do?

注意:http://httpbin.org/post使用JSON回复,其中包含有关已发送请求的详细信息.

结果:

{
  "args": {}, 
  "data": "hello world!\nhow do you do?\n", 
  "files": {}, 
  "form": {}, 
  "headers": {
    "Accept": "*/*", 
    "Accept-Encoding": "gzip,deflate", 
    "Connection": "close", 
    "Content-Length": "28", 
    "Host": "httpbin.org", 
    "User-Agent": "node-fetch/1.0 (+https://github.com/bitinn/node-fetch)"
  }, 
  "json": null, 
  "origin": "86.247.18.156", 
  "url": "http://httpbin.org/post"
}

如果您需要将文件作为包含更多参数的表单的一部分发送,您可以尝试:

• npm install form-data
• 传递一个FormData对象作为主体(FormData是一种Stream,通过库)CombinedStream
• 不要传递header选项(与上面的例子不同)

然后这个工作:

const formData = new FormData();
formData.append('file', fs.createReadStream('foo.txt'));
formData.append('blah', 42);
fetch('http://httpbin.org/post', {
    method: 'POST',
    body: formData
})

结果(只显示发送的内容):

----------------------------802616704485543852140629
Content-Disposition: form-data; name="file"; filename="foo.txt"
Content-Type: text/plain

hello world!
how do you do?

----------------------------802616704485543852140629
Content-Disposition: form-data; name="blah"

42
----------------------------802616704485543852140629--