[英]How to send data from React front-end to Nodejs Express back-end on button click
[英]How to send a form input data containing both image and text from React front-end to Express backend using Multer
当我测试发送包含从用户那里抓取的图像和文本的请求时,当我使用 Postman 时,它会以正确的数据传递到后端。 不过,不是来自 React 前端。 请求确实通过了,但是当我从后端 console.log 时, req.body 似乎是空的。 我究竟做错了什么? 我正在使用 Multer。
//FRONT-END
import React, { useState } from 'react';
import axios from 'axios';
const ListProperty = (props) => {
const [address, setAddress] = useState('');
const [file, setFile] = useState(null);
const [filename, setFilename] = useState('Choose File');
const handleAddressChange = (evt) => {
setAddress(evt.target.value);
};
const handlePhotoSelect = (evt) => {
setFile(evt.target.files[0]);
setFilename(evt.target.files[0].name);
};
const handleSubmit = async (evt) => {
evt.preventDefault();
const formData = new FormData();
formData.append('address', address);
formData.append('upload', file);
console.log(formData);
try {
axios.post('http://localhost:3000/listproperty', {
headers: { 'Content-Type': 'multipart/form-data' },
body: formData,
});
} catch (err) {
console.log(err);
}
};
return (
<div>
<h2>Property Listing Form</h2>
<span>Provide property address and Photo</span>
<form onSubmit={handleSubmit}>
<input
type="text"
value={address}
onChange={handleAddressChange}
name={address}
placeholder="Enter address"
/>
<br />
<input type="file" onChange={handlePhotoSelect} />
<button>Click to list</button>
</form>
</div>
);
};
export default ListProperty;
//BACK-END
const express = require('express');
const PropertyModel = require('../models/propertyModel');
const router = new express.Router();
const UserModel = require('../models/userModel');
const multer = require('multer');
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, 'public/images');
},
filename: function (req, file, cb) {
const uniqueName = `${Math.random().toString(32).slice(2)}.jpg`;
req.image = uniqueName;
cb(null, uniqueName);
},
});
const upload = multer({ storage });
router.post(
'/listproperty',
upload.single('upload'),
async (req, res) => {
console.log('hitting Backend router');
const property = new PropertyModel({
...req.body,
owner: req.user._id,
photo: req.image,
});
await UserModel.findByIdAndUpdate(req.user._id, {
$push: { properties: property._id },
});
try {
await property.save();
res.status(200).send(property);
} catch (err) {
console.log(err);
res.status(400).send(err);
}
}
);
module.exports = router;
您的 axios 请求不正确。 axios post 请求接受数据作为第二个参数,第三个参数用于选项(标头等),
axios.post('http://localhost:3000/listproperty', formData, {
headers: {
'Content-Type': 'multipart/form-data'
}
});
另一件事是您的请求根本没有被触发。 尝试将输入类型设置为提交,而不是使用按钮来触发表单的 onSubmit 处理程序。
<form onSubmit={handleSubmit}>
<input
type="text"
value={address}
onChange={handleAddressChange}
name={address}
placeholder="Enter address"
/>
<br />
<input type="file" onChange={handlePhotoSelect} />
<input type="submit" value="Submit" />
</form>
如果您在正文中发送表单数据,则需要使用强大的npm 模块
您可以使用npm i formidable
安装它,然后在文件顶部要求 formidable
var formidable = require("formidable");
router.post(
'/listproperty',
upload.single('upload'),
async (req, res) => {
var form = new formidable.IncomingForm();
form.multiples = false;
form.parse(req, async function (err, fields, files) {
/**now here you can get all files in files and fields with fields
in your case you have sent
formData.append('address', address);
formData.append('upload', file);
above two data in form
so you can get your image from files.upload
and address fields.address **/
})
})
另外,我建议您使用 Axios 进行 api 调用
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