我有一个react.js redux-form可以工作并将数据发布回我的API,但我还需要让提交者上传一张带有表单的图片,理想情况下是预览。我有点挣扎,已经到达了dropzone.js,但我似乎无法让我的表单实际发回图像数据。
render () {
const FILE_FIELD_NAME = 'files';
const renderDropzoneInput = (field) => {
const files = field.input.value;
return (
<div>
<Dropzone
name={field.name}
onDrop={( filesToUpload, e ) => field.input.onChange(filesToUpload)}
>
<div>Try dropping some files here, or click to select files to upload.</div>
</Dropzone>
{field.meta.touched &&
field.meta.error &&
<span className="error">{field.meta.error}</span>}
{files && Array.isArray(files) && (
<ul>
{ files.map((file, i) => <li key={i}>{file.name}<img src={file.preview}/></li>) }
</ul>
)}
</div>
);
}
return (
<form onSubmit={this.props.handleSubmit(this.onSubmit)}>
<div className="form-group">
<Field name="files" component={renderDropzoneInput} />
</div>
<button type="submit" className="btn btn-default">Submit</button>
</form>
);
}
files
变量确实被POST回到API,这很棒,但它包含以下内容:
[preview=blob:http://localhost:3000/bed3762e-a4de-4d19-8039-97cebaaca5c1]
有人可以建议我如何将实际二进制数据输入该变量吗?
此处提供完整代码https://github.com/rushughes/dsloracle/blob/master/client/src/components/LandCreate/index.js
答案 0 :(得分:2)
file-upload
功能的步骤:(如何处理API中的图像数据)将您的redux-form值附加到FormData实例。
let formData = new FormData();
formData.append('myFile', files[0]);
通过axios或multipart/form-data
库向客户发送fetch
个请求:
在您的API中接收multipart/form-data
请求,使用multer处理该请求,然后将文件写入disk storage
或memory storage
,如下所示:
$ npm install --save multer
const multer = require('multer')
const storage = multer.diskStorage({
destination: function (req, file, cb) {
cb(null, '/tmp/my-uploads')
},
filename: function (req, file, cb) {
cb(null, file.fieldname + '-' + Date.now())
}
})
const upload = multer({ storage: storage })
const app = express()
app.post('/upload', upload.single('myFile'), (req, res, next) => {
// req.file is the `myFile` file
// req.body will hold the text fields, if there were any
})
(可选)使用Express Serve-Static
答案 1 :(得分:2)
我最近有一个类似的问题并通过使用FileReader API将blob url转换为Base64(也可以转换为二进制字符串)来解决它。
然后将Base64或二进制字符串发送到服务器。
我的示例代码:
onDrop(acceptedFiles: any): any {
let images: any = this.state.Images;
acceptedFiles.forEach((file: any) => {
const reader: FileReader = new FileReader();
reader.onload = () => {
const fileAsBase64: any = reader.result.substr(reader.result.indexOf(",") + 1);
images.push(fileAsBase64);
};
reader.onabort = () => console.log("file reading was aborted");
reader.onerror = () => console.log("file reading has failed");
reader.readAsDataURL(file);
});
this.setState(prevState => ({
Images: images,
}));
}
如果您想发送二进制字符串而不是base64,请将reader.readAsDataURL(file);
更改为reader.readAsBinaryString(file);
此行:const fileAsBase64: any = reader.result.substr(reader.result.indexOf(",") + 1);
可简化为const file: any = reader.result;
答案 2 :(得分:1)
React.js有Dropzone可用的解决方案。请参考以下内容:
http://reactdropzone.azurewebsites.net/example/
这里可以找到哪些代码: https://react.rocks/example/React-Dropzone
更多这些解决方案也将以某种方式帮助您解决问题:
https://github.com/react-dropzone/react-dropzone
https://medium.com/technoetics/handling-file-upload-in-reactjs-b9b95068f6b
http://blog.mauriziobonani.com/dropzone.js-react.js-and-fluxxor-integration/
https://css-tricks.com/image-upload-manipulation-react/
https://www.reddit.com/r/reactjs/comments/6k6fjr/reactdropzone_integration_with_react/
答案 3 :(得分:0)
使用节点服务器处理图片上传
尝试使用formidable
在服务器端点函数中捕获文件app.post('/upload', function (req, res) { // express endpoint
var form = new formidable.IncomingForm();
form.parse(req, function(err, fields, files) { // "req" is server request object
fs.rename(files.file.path, "/tmp/" + files.file.name); // move file to desired location
});
// handle rest of text fields from req.body if there are any
});
这是node express示例,但您可以使用节点http作为强大的示例