Question

我是学习全栈开发的新手，特别是后端方面的东西，我试图让这个异步的Nodejs得到解决。

我需要在提交忘记密码表单后完成一些后端操作。基本上控制器动作看起来像这样（我知道肯定是以错误的方式）：

forgot: function (req, res) {
    var token = "febfoebfoui38383303cnc";
    var userEmail = req.body.email;
    var host = req.headers.host;

    AuthService.saveResetPasswordValues(token, userEmail, function (err, savedRecord) {
        if (err) { return res.send(404, '\n\nerror occurred\n\n'); }
        return res.json(savedRecord);
    });

    AuthService.sendForgotPasswordEmail(token, userEmail, host, function (err, message) {
        if (err) { return res.send(404, '\n\nerror occurred\n\n'); }
        return res.json(message);
    });
},

每项服务都可以帮助您重置密码重置电子邮件。

saveResetPasswordValues: function (token, userEmail, cb) {
    var expiration = Date.now() + 3600000; // 1 hour
    User.update({ email: userEmail },
        { resetPasswordToken: token,
            resetPasswordExpires: expiration})
        .exec(function (err, user) {
            if (err) { return cb({ status: 404, message: 'Could not find user with that email address' }); }
            return cb(err, user);
        });
},

sendForgotPasswordEmail: function (token, userEmail, host, cb) {
    var htmlMessage =
        '<h4>You are receiving this because you (or someone else) have requested the reset of the password for your account.</h4>' +
        '<p>Please click on the following link, or paste this into your browser to complete the process:</p>' +
        "<p><a href='http://" + host + '/reset/' + token + "'> Link to password reset </a></p>" +
        '<p>If you did not request this, please ignore this email and your password will remain unchanged.</p>';

    var emailInfo = {
        to: userEmail,
        from: "customerservice@smallchangeproj.com",
        subject: "Small Change Project Password Reset",
        message: htmlMessage,
        fromName: "Small Change Project"
    };

    .... some code for sending the email ...

     return cb(null, 'email has been sent');

}

最后，用户应该收到如下所示的电子邮件：

您收到的是因为您（或其他人）要求的   重置您帐户的密码。

请点击以下链接，或将其粘贴到您的浏览器中   完成这个过程：

Link to password reset

令人惊讶的是，这段代码确实有效，但是它吐出了一堆丑陋的错误 - 告诉我我不知道异步回调是如何工作的;）

error: Sending 500 ("Server Error") response: 
 Error: Can't set headers after they are sent.
    at ServerResponse.OutgoingMessage.setHeader (http.js:690:11)
    at ServerResponse.res.setHeader (/usr/lib/node_modules/sails/node_modules/express/node_modules/connect/lib/patch.js:133:22)
    at ServerResponse.res.set.res.header (/home/zacharyhustles/smallChangeAPI/node_modules/sails/node_modules/express/lib/response.js:577:10)
    at ServerResponse.res.send (/home/zacharyhustles/smallChangeAPI/node_modules/sails/node_modules/express/lib/response.js:142:12)
    at ServerResponse.res.json (/home/zacharyhustles/smallChangeAPI/node_modules/sails/node_modules/express/lib/response.js:223:15)
    at /home/zacharyhustles/smallChangeAPI/api/controllers/UserController.js:123:15
    at /home/zacharyhustles/smallChangeAPI/api/services/AuthService.js:50:4
    at Object.module.exports.simpleSendEmail (/home/zacharyhustles/smallChangeAPI/api/services/EmailService.js:48:12)
    at Object.bound [as simpleSendEmail] (/home/zacharyhustles/smallChangeAPI/node_modules/lodash/dist/lodash.js:729:21)
    at Object.module.exports.sendForgotPasswordEmail (/home/zacharyhustles/smallChangeAPI/api/services/AuthService.js:46:16)
    at Object.bound [as sendForgotPasswordEmail] (/home/zacharyhustles/smallChangeAPI/node_modules/lodash/dist/lodash.js:729:21)
    at Object.module.exports.forgot (/home/zacharyhustles/smallChangeAPI/api/controllers/UserController.js:121:15)
    at bound (/home/zacharyhustles/smallChangeAPI/node_modules/lodash/dist/lodash.js:729:21)
    at routeTargetFnWrapper (/home/zacharyhustles/smallChangeAPI/node_modules/sails/lib/router/bind.js:179:5)
    at callbacks (/home/zacharyhustles/smallChangeAPI/node_modules/sails/node_modules/express/lib/router/index.js:164:37)
    at param (/home/zacharyhustles/smallChangeAPI/node_modules/sails/node_modules/express/lib/router/index.js:138:11) [Error: Can't set headers after they are sent.]

这样做的正确方法是什么？我还想将逻辑分成两种服务方法......

Answer 1

与已经建议的错误消息一样，在您已经发送了一个响应之后，不允许向浏览器发送另一个响应，因为在网页请求的经典请求 - 响应周期中，浏览器每个请求只接受一个响应。

您必须将第二个服务功能的调用放入第一个服务功能的回调中，并将服务助手的结果发送到组合对象中，例如：像这样：

    forgot: function (req, res) {
        var token = "febfoebfoui38383303cnc";
        var userEmail = req.body.email;
        var host = req.headers.host;

        AuthService.saveResetPasswordValues(token, userEmail, function (err, savedRecord) {
            if (err) { return res.send(404, '\n\nerror occurred\n\n'); }

            AuthService.sendForgotPasswordEmail(token, userEmail, host, function (err, message) {
                if (err) { return res.send(404, '\n\nerror occurred\n\n'); }
                // make sure to adapt your client logic for this response
                return res.json({savedRecord: savedRecord, message: message);
            });
        });
    },

异步回调的一般结论是，如果你有一个依赖于前一个调用结果的函数调用，你必须将第二个调用始终嵌入到前一个调用的回调中，所以它们会在正确的顺序和第二个调用可以访问第一个的结果。

如果要在一个响应中发送多个异步函数的结果，只需嵌套函数调用，以便在最后最深的回调中访问所有结果。

SailsJS使用一个Controller操作调用两个Service方法

1 个答案: