Node.js文件大小限制配置问题：仍遇413错误求助

已做的配置尝试：

• Nginx反向代理配置：

location /api/ {
        client_max_body_size 20M;
}

• Node.js（Express）入口文件配置：

var path = require('path');
var http = require('http');
const auth = require('./middleware/auth');
var oas3Tools = require('oas3-tools');
const bodyParser = require('body-parser');
const express = require('express');
var options = {

    openApiValidator: {
        // Details of options see here
        // https://github.com/cdimascio/express-openapi-validator/wiki/Documentation#openapivalidator-middleware-options
        apiSpec: path.join(__dirname, 'api/openapi.yaml'),
        validateSecurity: {
            handlers: {
                bearerAuth: auth.authenticateToken,
            },
        },
    },
    routing: {
        controllers: path.join(__dirname, './controllers')
    },
    middleware: {
        pre: [
            express.json({ limit: '50mb' }),
            express.urlencoded({ limit: '50mb', extended: true }),
            (req, res, next) => {
                res.header('Access-Control-Allow-Origin', '*');
                res.header('Access-Control-Allow-Methods', 'GET, POST, PUT, DELETE, OPTIONS');
                res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-With, Content-Type, Accept, Authorization');
                next();
            }
        ]
    }
};



var expressAppConfig = oas3Tools.expressAppConfig(path.join(__dirname, 'api/openapi.yaml'), options);
var app = expressAppConfig.getApp();

app.use(cors({
    origin: '*',
    credentials: true
}));
// Initialize the Swagger middleware
http.createServer(app).listen(serverPort, function () {
    console.log('Your server is listening on port %d (http://localhost:%d)', serverPort, serverPort);
    console.log('Swagger-ui is available on http://localhost:%d/docs', serverPort);
});

• 额外尝试：添加了parserLimit: '1mb'配置，但仍无效。

目前问题：仍收到413错误，经TCP追踪确认错误由Node.js返回，推测是Express默认100KB的大小限制问题，但不知如何修改该配置，恳请帮助。

内容的提问来源于stack exchange，提问作者Andrea__yk