Question

module.exports.getTragos = function(req, res) {
    var connection = conectar();
    connection.connect();

    connection.query('SELECT * from tipoAlcohol', function(err, rows, fields) {
        if (!err)
            return JSON.stringify(rows));
        else
            return  'Error while performing Query.';
    });

    connection.end();
}

我想让getTragos函数返回执行的查询行，但是return JSON.stringify(rows));没有返回它们。我试着放console.log(rows)，查询执行得很好。

这是调用getTragos的代码：

module.exports.iniciar = function(app) {
    app.get('/bebidas/getTipoAlcohol', function (req, res) {
        res.send(modelo.getTragos());
    });
}

Answer 1

只需将结果写回来，就像这样。

module.exports.iniciar = function(app) {
    app.get('/bebidas/getTipoAlcohol', function(req, res, next) {
      modelo.getTragos(function(err, tragos) {
        if(err) {return next(err);}
        //do you processing here
        // then write the result to the response
        var result = doSomething(tragos); // i am assuming that doSomething is synchronous. 
        res.json(result);
      });
    });
}

module.exports.getTragos = function(callback) {
    var connection = conectar();
    connection.connect();

    connection.query('SELECT * from tipoAlcohol', function(err, rows, fields) {
        connection.end();
        if (!err)
            return callback(null, rows);
        else
            return callback('Error while performing Query.');
    });

}

注意，我改变了两种方法的签名。

Answer 2

module.exports.getTragos = function(req, res, callback) {
    var connection = conectar();
    connection.connect();

    connection.query('SELECT * from tipoAlcohol', function(err, rows, fields) {
        if (!err)
            callback(rows);               
        else
            return  'Error while performing Query.';
    });

    connection.end();
}


module.exports.iniciar = function(app) {
    app.get('/bebidas/getTipoAlcohol', function (req, res) {
        modelo.getTragos(req, res, function(returnedValue){
            res.send(returnedValue);
        });        
    });
}

Answer 3

不要使用JSON.stringify（），只返回行。

nodejs mysql查询返回select语句的值

3 个答案: