node.js 回调函数

Question

我想通过 "SHA512crypto" 回调函数接收结果值，并将其用作 client.query 中的值。但是无论我多么努力，我都只能得到未定义的值。请no.js初学者给出解决方案

var SHA512crypto = function (KeyValue, callback) {
    crypto.randomBytes(64, (err, buf) => {
        crypto.pbkdf2(KeyValue, buf.toString('base64'), 97325, 64, 'sha512', (err, key) => {
            //console.log(key.toString('base64'));

            callback(err, key.toString('base64'));
            return;
        });
    });
}

// Socket SignUp Data
var socketSignUp = function (SignUpData, callback) {
    var SignUpSQL = 'insert into userinfo values(, , , , , , , )';
    var companyInfoSQL ='update companyinfo set address = , company_number = , company_phonenumber = , Business_license_number =  where company_code = ';
    var companyInfoValues = [SignUpData.address, SignUpData.admin_company_number, SignUpData.admin_phone_number, SignUpData.businessLicense, SignUpData.company_code];
    var LoginInfoSQL = 'insert into logininfo(email, status, company_code) values(, , )';
    var LoginInfoValues = [SignUpData.email, "false", SignUpData.company_code];
    var TimeStampNumSQL = 'SELECT timestamp FROM userinfo ORDER BY timestamp DESC LIMIT 1';

    client.query(TimeStampNumSQL, (err, res) => {
        if (res) {
            var SignUpValues = [res.rows[0].timestamp + 1, SignUpData.admin, SHA512crypto(SignUpData.email), SHA512crypto(SignUpData.password), SignUpData.name, SignUpData.company_code, SignUpData.company_number, SignUpData.phone_number];
            client.query(SignUpSQL, SignUpValues);
            if (SignUpData.admin == "admin") {
                client.query(companyInfoSQL, companyInfoValues);
            }
            client.query(LoginInfoSQL, LoginInfoValues);
        }
    });
}

Answer 1

我的建议是转换为 Promise，然后您可以使用 Promise.all() 等待多个异步操作完成。实际上，我想将所有这些回调转换为 promises 并大量清理代码，但这里有一个修改，对 promises 的转换最少，并添加了一些错误处理：

var SHA512crypto = function (KeyValue) {
    return new Promise(function(resolve, reject) {
        crypto.randomBytes(64, (err, buf) => {
            if (err) return reject(err);
            crypto.pbkdf2(KeyValue, buf.toString('base64'), 97325, 64, 'sha512', (err, key) => {
                //console.log(key.toString('base64'));
                if (err) return reject(err);
                resolve(key.toString('base64'))
            });
        });
    });
}

// Socket SignUp Data
var socketSignUp = function (SignUpData, callback) {
    var SignUpSQL = 'insert into userinfo values(, , , , , , , )';
    var companyInfoSQL ='update companyinfo set address = , company_number = , company_phonenumber = , Business_license_number =  where company_code = ';
    var companyInfoValues = [SignUpData.address, SignUpData.admin_company_number, SignUpData.admin_phone_number, SignUpData.businessLicense, SignUpData.company_code];
    var LoginInfoSQL = 'insert into logininfo(email, status, company_code) values(, , )';
    var LoginInfoValues = [SignUpData.email, "false", SignUpData.company_code];
    var TimeStampNumSQL = 'SELECT timestamp FROM userinfo ORDER BY timestamp DESC LIMIT 1';

    client.query(TimeStampNumSQL, (err, res) => {
        if (err) {
            callback(err);
            return;
        }
        if (res) {
            Promise.all([SHA512crypto(SignUpData.email), SHA512crypto(SignUpData.password)])
              .then(([emailCrypto, passwordCrypto]) => {
                  var SignUpValues = [res.rows[0].timestamp + 1, SignUpData.admin, emailCrypto, passwordCrypto, SignUpData.name, SignUpData.company_code, SignUpData.company_number, SignUpData.phone_number];
                  client.query(SignUpSQL, SignUpValues);
                  if (SignUpData.admin == "admin") {
                      client.query(companyInfoSQL, companyInfoValues);
                  }
                  client.query(LoginInfoSQL, LoginInfoValues);
              }).catch(callback);
        }
    });
}

你的所有 client.query() 命令似乎都应该有回调和错误处理，而且你似乎没有正确排序其中的一些命令以等待第一个命令在运行下一个。但是，这些是与您提出的问题不同的问题。

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