Flask获取文件列表接口报错：TypeError: get()缺少必填参数ident

错误根源 #

你的报错核心是**Upload模型未定义json()方法**——SQLAlchemy的Model类默认不提供该方法，当你在getFiles中调用x.json()时，会触发内部方法调用错误，最终抛出get()参数缺失的异常。另外还有两处细节问题需要修正：

修复步骤 #

1. 给Upload模型添加序列化方法 #

在Upload类中新增json()方法，返回可序列化的模型数据字典（注意不要包含二进制的data字段，无法直接转为JSON）：

class Upload(db.Model):
    id=db.Column(db.Integer, primary_key=True)
    filename = db.Column(db.String(50))
    data = db.Column(db.LargeBinary)

    def json(self):
        return {
            'id': self.id,
            'filename': self.filename
        }

2. 修正配置项拼写错误 #

将SQLALCHEMY_TRACK_MODIFICATIONs改为正确的SQLALCHEMY_TRACK_MODIFICATIONS（末尾字母大写S），否则会触发SQLAlchemy警告：

app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

3. 修复路由中ID类型不匹配问题 #

download和delete路由的upload_id是字符串类型，而数据库id为整数，需转换后再查询，避免匹配失败：

@app.route('/download/<upload_id>')
def download(upload_id):
    upload = Upload.query.filter_by(id=int(upload_id)).first()
    if not upload:
        return {'message': 'File not found'}, 404
    return send_file(BytesIO(upload.data), attachment_filename=upload.filename , as_attachment=True)

@app.route('/delete/<upload_id>')
def delete(upload_id):
    f = Upload.query.filter_by(id=int(upload_id)).first()
    if f: 
        db.session.delete(f)
        db.session.commit()
        return {'message':'Deleted'}
    else:
        return {'message':'File not found'},404

修改后的完整app.py代码 #

from io import BytesIO
from flask import Flask , render_template, request , send_file
from flask_sqlalchemy import SQLAlchemy
from flask_restful import Api, Resource, reqparse 
from flask_cors import CORS, cross_origin

app= Flask(__name__)
CORS(app)
app.config['SQLALCHEMY_DATABASE_URI']='sqlite:///data.db'
app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

class Upload(db.Model):
    id=db.Column(db.Integer, primary_key=True)
    filename = db.Column(db.String(50))
    data = db.Column(db.LargeBinary)

    def json(self):
        return {
            'id': self.id,
            'filename': self.filename
        }

@app.route('/' , methods=['GET', 'POST'])
def index():
    if request.method == 'POST':
        file= request.files['file']
        upload = Upload(filename=file.filename, data=file.read()) 
        db.session.add(upload)
        db.session.commit()
        return f'Uploaded: {file.filename}' 
    return render_template('index.html')

@app.route('/files', methods=['GET'])
def getFiles():
    files = Upload.query.all()
    return {'Files': [x.json() for x in files]}

@app.route('/download/<upload_id>')
def download(upload_id):
    upload = Upload.query.filter_by(id=int(upload_id)).first()
    if not upload:
        return {'message': 'File not found'}, 404
    return send_file(BytesIO(upload.data), attachment_filename=upload.filename , as_attachment=True)

@app.route('/delete/<upload_id>')
def delete(upload_id):
    f = Upload.query.filter_by(id=int(upload_id)).first()
    if f: 
        db.session.delete(f)
        db.session.commit()
        return {'message':'Deleted'}
    else:
        return {'message':'File not found'},404

# 首次运行时创建数据库表
with app.app_context():
    db.create_all()

额外说明 #

• 不要在json()方法中返回data字段，二进制文件内容无法直接序列化为JSON，前端需通过/download/<id>接口下载文件。
• 首次运行代码时，with app.app_context(): db.create_all()会自动创建SQLite数据库表，避免表不存在的报错。

内容的提问来源于stack exchange，提问作者user16001720