javascript - Flask 和 ReactJS 文件上传不起作用

Question

我是Python Flask的新手，我在后端使用Flask，在前端使用React JS，并在数据库中使用Pymongo。我想将文件从 ReactJs 上传到 Flask 服务器，在执行“第二个”方法时遇到错误，我该怎么做。下面是我尝试过的代码。

我尝试了两个例子，一个有效，另一个无效，我不知道为什么。

werkzeug.exceptions.BadRequestKeyError:400 错误请求:浏览器(或代理)发送了该服务器无法理解的请求。 KeyError:'文件'

1. 直接将文件发送到 API。 案例1

Python代码

import os
from flask import Flask, flash, request, redirect, url_for
from werkzeug.utils import secure_filename

UPLOAD_FOLDER = '/path/to/the/uploads'
ALLOWED_EXTENSIONS = set([ 'png', 'jpg', 'jpeg'])

app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
@app.route('/api/users/add_photo', methods=['POST', "GET"])
def upload_file():
    if request.method == 'POST':
        # check if the post request has the file part
        if 'file' not in request.files:
            flash('No file part')
            return redirect(request.url)
        file = request.files['file']
        # if user does not select file, browser also
        # submit a empty part without filename
        if file.filename == '':
            flash('No selected file')
            return redirect(request.url)
        if file and allowed_file(file.filename):
            filename = secure_filename(file.filename)
            file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
            image = upload(open(filename, 'rb'))
            user_id = user.insert({"file":image})
            return jsonify({'result': "file Upload successfully!!!"})

onSubmitImage(e) {
    let file = this.state.file;
    let formData = new FormData();
    formData.append("file", file);
    this.props.imageUpload(formData);
  }

上面的例子运行良好

将文件发送到对象中的 API。 案例2

Python代码

import os
from flask import Flask, flash, request, redirect, url_for
from werkzeug.utils import secure_filename

UPLOAD_FOLDER = '/path/to/the/uploads'
ALLOWED_EXTENSIONS = set([ 'png', 'jpg', 'jpeg'])

app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
@app.route('/api/users/add_photo', methods=['POST', "GET"])
def upload_file():
    if request.method == 'POST':
        # check if the post request has the file part
        if 'file' not in request.files:
            flash('No file part')
            return redirect(request.url)
        file = request.files['file']
        name = request.get_json(force=True)["name"]
        last_name = request.get_json(force=True)["last_name"]
        email = request.get_json(force=True)["email"]
        # if user does not select file, browser also
        # submit a empty part without filename
        if file.filename == '':
            flash('No selected file')
            return redirect(request.url)
        if file and allowed_file(file.filename):
            filename = secure_filename(file.filename)
            file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
            image = upload(open(filename, 'rb'))
            user_id = user.insert({"file":image,"name":name,"last_name":last_name,"email":email})
            return jsonify({'result': "file Upload successfully!!!"})

 onSubmitImage(e) {
    let file = this.state.file;
    let formData = new FormData();
    formData.append("file", file);
    const data = {
      file: formData
      name: this.state.name
      last_name: this.state.last_name
      email: this.state.last_name
    };
    this.props.imageUpload(data);
  }

我不知道为什么第一个有效而第二个无效。我想实现第二个示例，因为还有其他数据，例如姓名、姓氏、带有图像文件的电子邮件。

Answer 1

您需要将数据添加到 FormData() - 即

let file = this.state.file;
let formData = new FormData();
formData.append("file", file);
formData.append("name", this.state.name);
formData.append("last_name", this.state.last_name)
formData.append("email", this.state.last_name)
this.props.imageUpload(formData);