💡 学习flask是因为大创，需求是接收微信小程序发送来的音频，而后由学长的算法对该音频进行分析。

后端接收文件上传

原生flask使用的是request包

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from werkzeug.utils import secure_filename
from flask import request

@app.route('/upload', methods=['GET', 'POST'])
def upload_file():
    if request.method == 'POST':
        file = request.files['the_file']
        file.save(f"/var/www/uploads/{secure_filename(file.filename)}")

但尝试这样接收小程序上传的文件时，报错

'Request' object has no attribute 'File'

经过搜索得知，微信小程序的文件被包裹在FileField中，无法靠Request.file检索

要处理FileField式的文件上传，需要使用另外两个包

教程见 How to Handle File Uploads with Flask

我最终的代码如下, flask确实轻量，只用了30行不到

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from flask import Flask
from flask_wtf import FlaskForm
from flask_wtf.file import FileField
from flask_uploads import configure_uploads,UploadSet,AUDIO

app = Flask(__name__)
# 进入调试模式
app.debug = True
#必须以UPLOADED_XXX_DEST的形式设置文件存放的地址，XXX取决于UploadSet的变量名大写形式
app.config['UPLOADED_SOUNDS_DEST'] = './uploads'
#必须设置密匙，否则会报跨域错误
app.config['SECRET_KEY'] = 'heyheyhey'
# UploadSet的第二个参数取决于上传文件的形式，有哪些形式请自行翻看源码
sounds = UploadSet('sounds',AUDIO)
configure_uploads(app,sounds)

class MyForm(FlaskForm):
    sound = FileField('sound')

@app.route("/upload2",methods=['POST'])
def upload():
    form = MyForm()
    filename = sounds.save(form.sound.data)
    return filename

if __name__ == '__main__':
    app.run(debug=True)