如何使用redux-form上传文件？

Question

尝试上载文件时，无法将正确的值放入存储区。我得到的不是文件内容，而是类似{ 0: {} }的内容。代码如下：

const renderInput = field => (
  <div>
    <input {...field.input} type={field.type}/>
    {
      field.meta.touched &&
      field.meta.error &&
      <span className={styles.error}>{field.meta.error}</span>
    }
  </div>
);

render() {

  ...

  <form className={styles.form} onSubmit={handleSubmit(submit)}>
    <div className={styles.interface}>
      <label>userpic</label>
      <Field
        name="userpic"
        component={renderInput}
        type="file"
      />
    </div>
    <div>
      <button type="submit" disabled={submitting}>Submit</button>
    <div>
  </form>

  ...

}

我在网上找到的所有示例都是使用redux-form的v5创建的。

如何在redux-form v6中进行文件输入？

Answer 1

创建一个Field组件，如下所示：

import React, {Component} from 'react'

export default class FieldFileInput  extends Component{
  constructor(props) {
    super(props)
    this.onChange = this.onChange.bind(this)
  }

  onChange(e) {
    const { input: { onChange } } = this.props
    onChange(e.target.files[0])
  }

  render(){
    const { input: { value } } = this.props
    const {input,label, required, meta, } = this.props  //whatever props you send to the component from redux-form Field
    return(
     <div><label>{label}</label>
     <div>
       <input
        type='file'
        accept='.jpg, .png, .jpeg'
        onChange={this.onChange}
       />
     </div>
     </div>
    )
}
}

将此组件传递给您需要的Field组件。如果你想要一个简单的文件上传功能，不需要额外的Dropzone或其他库。

Answer 2

我使用Dropzone的redux表单输入包装器的示例

import React, {Component, PropTypes} from 'react';
import Dropzone from 'react-dropzone';
import { Form } from 'elements';
import { Field } from 'redux-form';

class FileInput extends Component {
  static propTypes = {
    dropzone_options: PropTypes.object,
    meta: PropTypes.object,
    label: PropTypes.string,
    classNameLabel: PropTypes.string,
    input: PropTypes.object,
    className: PropTypes.string,
    children: PropTypes.node,
    cbFunction: PropTypes.func,
  };

  static defaultProps = {
    className: '',
    cbFunction: () => {},
  };

  render() {
    const { className, input: { onChange }, dropzone_options, meta: { error, touched }, label, classNameLabel, children, name, cbFunction } = this.props;

    return (
      <div className={`${className}` + (error && touched ? ' has-error ' : '')}>
        {label && <p className={classNameLabel || ''}>{label}</p>}
        <Dropzone
          {...dropzone_options}
          onDrop={(f) => {
            cbFunction(f);
            return onChange(f);
          }}
          className="dropzone-input"
          name={name}
        >
          {children}
        </Dropzone>
        {error && touched ? error : ''}
      </div>
    );
  }
}
export default props => <Field {...props} component={FileInput} />;

使用起来很热：

<FileInput
 name="add_photo"
 label="Others:"
  classNameLabel="file-input-label"
  className="file-input"
  dropzone_options={{
    multiple: false,
    accept: 'image/*'
  }}
>
  <span>Add more</span>
</FileInput>

Answer 3

另一种方法是渲染预览图像(下面的示例使用React API语法，只接受单个图像文件发送到16+；但是，通过一些细微的调整，它还可以缩放到多个图像和其他字段输入)：

工作示例：https://codesandbox.io/s/m58q8l054x

工作示例(过时)：https://codesandbox.io/s/8kywn8q9xl

之前的

​

​

之后的

​

​

containers/UploadForm.js

import React, { Component } from "react";
import { Form, Field, reduxForm } from "redux-form";
import DropZoneField from "../components/dropzoneField";

const imageIsRequired = value => (!value ? "Required" : undefined);

class UploadImageForm extends Component {
  state = { imageFile: [] };

  handleFormSubmit = formProps => {
    const fd = new FormData();
    fd.append("imageFile", formProps.imageToUpload.file);
    // append any additional Redux form fields
    // create an AJAX request here with the created formData

    alert(JSON.stringify(formProps, null, 4));
  };

  handleOnDrop = (newImageFile, onChange) => {
    const imageFile = {
      file: newImageFile[0],
      name: newImageFile[0].name,
      preview: URL.createObjectURL(newImageFile[0]),
      size: newImageFile[0].size
    };

    this.setState({ imageFile: [imageFile] }, () => onChange(imageFile));
  };

  resetForm = () => this.setState({ imageFile: [] }, () => this.props.reset());

  render = () => (
    <div className="app-container">
      <h1 className="title">Upload An Image</h1>
      <hr />
      <Form onSubmit={this.props.handleSubmit(this.handleFormSubmit)}>
        <Field
          name="imageToUpload"
          component={DropZoneField}
          type="file"
          imagefile={this.state.imageFile}
          handleOnDrop={this.handleOnDrop}
          validate={[imageIsRequired]}
        />
        <button
          type="submit"
          className="uk-button uk-button-primary uk-button-large"
          disabled={this.props.submitting}
        >
          Submit
        </button>
        <button
          type="button"
          className="uk-button uk-button-default uk-button-large"
          disabled={this.props.pristine || this.props.submitting}
          onClick={this.resetForm}
          style={{ float: "right" }}
        >
          Clear
        </button>
      </Form>
      <div className="clear" />
    </div>
  );
}

export default reduxForm({ form: "UploadImageForm" })(UploadImageForm);

components/dropzoneField.js

import React from "react";
import PropTypes from "prop-types";
import DropZone from "react-dropzone";
import ImagePreview from "./imagePreview";
import Placeholder from "./placeholder";
import ShowError from "./showError";

const DropZoneField = ({
  handleOnDrop,
  input: { onChange },
  imagefile,
  meta: { error, touched }
}) => (
  <div className="preview-container">
    <DropZone
      accept="image/jpeg, image/png, image/gif, image/bmp"
      className="upload-container"
      onDrop={file => handleOnDrop(file, onChange)}
    >
      {({ getRootProps, getInputProps }) =>
        imagefile && imagefile.length > 0 ? (
          <ImagePreview imagefile={imagefile} />
        ) : (
          <Placeholder
            error={error}
            touched={touched}
            getInputProps={getInputProps}
            getRootProps={getRootProps}
          />
        )
      }
    </DropZone>
    <ShowError error={error} touched={touched} />
  </div>
);

DropZoneField.propTypes = {
  error: PropTypes.string,
  handleOnDrop: PropTypes.func.isRequired,
  imagefile: PropTypes.arrayOf(
    PropTypes.shape({
      file: PropTypes.file,
      name: PropTypes.string,
      preview: PropTypes.string,
      size: PropTypes.number
    })
  ),
  label: PropTypes.string,
  onChange: PropTypes.func,
  touched: PropTypes.bool
};

export default DropZoneField;

components/imagePreview.js

import React from "react";
import PropTypes from "prop-types";

const ImagePreview = ({ imagefile }) =>
  imagefile.map(({ name, preview, size }) => (
    <div key={name} className="render-preview">
      <div className="image-container">
        <img src={preview} alt={name} />
      </div>
      <div className="details">
        {name} - {(size / 1024000).toFixed(2)}MB
      </div>
    </div>
  ));

ImagePreview.propTypes = {
  imagefile: PropTypes.arrayOf(
    PropTypes.shape({
      file: PropTypes.file,
      name: PropTypes.string,
      preview: PropTypes.string,
      size: PropTypes.number
    })
  )
};

export default ImagePreview;

components/placeholder.js

import React from "react";
import PropTypes from "prop-types";
import { MdCloudUpload } from "react-icons/md";

const Placeholder = ({ getInputProps, getRootProps, error, touched }) => (
  <div
    {...getRootProps()}
    className={`placeholder-preview ${error && touched ? "has-error" : ""}`}
  >
    <input {...getInputProps()} />
    <MdCloudUpload style={{ fontSize: 100, paddingTop: 85 }} />
    <p>Click or drag image file to this area to upload.</p>
  </div>
);

Placeholder.propTypes = {
  error: PropTypes.string,
  getInputProps: PropTypes.func.isRequired,
  getRootProps: PropTypes.func.isRequired,
  touched: PropTypes.bool
};

export default Placeholder;

components/showError.js

import React from "react";
import PropTypes from "prop-types";
import { MdInfoOutline } from "react-icons/md";

const ShowError = ({ error, touched }) =>
  touched && error ? (
    <div className="error">
      <MdInfoOutline
        style={{ position: "relative", top: -2, marginRight: 2 }}
      />
      {error}
    </div>
  ) : null;

ShowError.propTypes = {
  error: PropTypes.string,
  touched: PropTypes.bool
};

export default ShowError;

styles.css

img {
  max-height: 240px;
  margin: 0 auto;
}

.app-container {
  width: 500px;
  margin: 30px auto;
}

.clear {
  clear: both;
}

.details,
.title {
  text-align: center;
}

.error {
  margin-top: 4px;
  color: red;
}

.has-error {
  border: 1px dotted red;
}

.image-container {
  align-items: center;
  display: flex;
  width: 85%;
  height: 80%;
  float: left;
  margin: 15px 10px 10px 37px;
  text-align: center;
}

.preview-container {
  height: 335px;
  width: 100%;
  margin-bottom: 40px;
}

.placeholder-preview,
.render-preview {
  text-align: center;
  background-color: #efebeb;
  height: 100%;
  width: 100%;
  border-radius: 5px;
}

.upload-container {
  cursor: pointer;
  height: 300px;
}