“req.getConnection 不是一个函数”Node.js

Question

我在将 Node.js 应用程序与 sql 数据库连接时遇到问题。发生错误是“req.getConnection 不是函数”。当我点击某个页面（例如用户）时，我试图从数据库中获取数据。

我的代码如下

应用程序.js

var express = require('express');
var path = require('path');
var favicon = require('serve-favicon');
var logger = require('morgan');
var cookieParser = require('cookie-parser');
var bodyParser = require('body-parser');
var flash = require('express-flash');
var session = require('express-session');
var expressValidator = require('express-validator');
var methodOverride = require('method-override');

var connection  = require('express-myconnection');
var mysql = require('mysql');

var routes = require('./routes/index');
var users = require('./routes/users');

var app = express();

// view engine setup
app.set('views', path.join(__dirname, 'views'));
app.set('view engine', 'jade');

// uncomment after placing your favicon in /public
//app.use(favicon(path.join(__dirname, 'public', 'favicon.ico')));
app.use(logger('dev'));
app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: false }));
app.use(session({secret:"mysecretpass"}));
app.use(flash());
app.use(expressValidator());
app.use(cookieParser());
app.use(require('less-middleware')(path.join(__dirname, 'public')));
app.use(express.static(path.join(__dirname, 'public')));

app.use('/', routes);
app.use('/users', users);

app.use(methodOverride(function(req, res){
 if (req.body && typeof req.body === 'object' && '_method' in req.body) 
  { 
      var method = req.body._method;
      delete req.body._method;
      return method;
    } 
  }));

/*-----------------------------------------
 * Connection peer, register as middleware
 * type koneksi:single,pool and request
 -----------------------------------------*/
app.use(
  connection(mysql,{
       host:'localhost',
       user:'root',
       password:'',
       port:3306,
       database:'stores'
   },'single')
   );


// catch 404 and forward to error handler
app.use(function(req, res, next) {
  var err = new Error('Not Found');
  err.status = 404;
  next(err);
});

// error handlers

// development error handler
// will print stacktrace
if (app.get('env') === 'development') {
  app.use(function(err, req, res, next) {
    res.status(err.status || 500);
    res.render('error', {
      message: err.message,
      error: err
    });
  });
}

// production error handler
// no stacktraces leaked to user
app.use(function(err, req, res, next) {
  res.status(err.status || 500);
  res.render('error', {
    message: err.message,
    error: {}
  });
});
module.exports = app;

路线/index.js

var express = require('express');
var router = express.Router();

/* GET home page. */
router.get('/', function(req, res, next) {
  res.render('dashboard', { title: 'Dashboard' });
});

router.get('/admin_users', function(req, res, next) {
    req.getConnection(function(err,connection){
        var query = connection.query('SELECT * FROM users',function(err,rows)
        {
            if(err)
                var errornya  = ("Error Selecting : %s ",err );   
            req.flash('msg_error', errornya);   
            res.render('admin_users',{title:"Admin Users",data:rows});
        });
         //console.log(query.sql);
     });
});

module.exports = router;

Answer 1

您要在中间件之后添加express-myconnection中间件。中间件按照添加的顺序执行，因此在执行中间件之前，不会在对象上定义该函数。routesgetConnectionreqexpress-myconnection

只需将连接中间件移至路由的使用上方即可，即。

app.use(
  connection(mysql,{
       host:'localhost',
       user:'root',
       password:'',
       port:3306,
       database:'stores'
   },'single')
);

app.use('/', routes);
app.use('/users', users);