如何调试 Node.js 中的标头发送错误

发布于 2024-12-03 22:30:30 字数 597 浏览 0 评论 0原文

我收到很多发送后无法设置标头错误，而且他们似乎从未在我的app.js中给我行号，这正常吗？人们如何调试这些错误？

我抛出标题错误的代码看起来像这样，它是否做了一些奇怪的事情来隐藏行号？

app.get('/', function(req, res, next) {
    if (req.param('q')) {
        searchProvider.search(
            req.param('q'),
            function( error, results) {
                res.render('search', {
                    locals: {
                        results: results,
                        q: req.param('q')
                    },
                });
            }
        );
    } else {
        res.render('index');
    }
});

原文

I'm getting a lot of Can't set headers after they are sent errors, and they never seem to give me line numbers in my app.js, is this normal? How do people debug these errors?

My code that is throwing the headers error looks like this, is it doing something weird to hide the line numbers?

app.get('/', function(req, res, next) {
    if (req.param('q')) {
        searchProvider.search(
            req.param('q'),
            function( error, results) {
                res.render('search', {
                    locals: {
                        results: results,
                        q: req.param('q')
                    },
                });
            }
        );
    } else {
        res.render('index');
    }
});

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不爱素颜 2024-12-10 22:30:30

发送后无法设置标头

是一个常见错误，这意味着您基本上调用 res.render、res.end 或 res.send 多次。这意味着您尝试向一个 HTTP 请求写入多个 HTTP 响应（这是无效的）。

此错误的一个常见原因是在一个中间件中调用 next 两次。

也许你有一个像这样的中间件

app.all("*", function(req, res, next) {
  // not logged in
  if (!req.user) {
    res.render("loginError");
  } 
  // bad accidental next call!! Will call next after rendering login error
  next();
});

Can't set headers after they are sent

Is a common error which means your basically calling res.render, res.end or res.send multiple times. This means your trying to write multiple HTTP responses to one HTTP request (this is invalid).

A common cause of this bug is calling next twice in a piece of middleware.

Maybe you have a piece of middleware like

app.all("*", function(req, res, next) {
  // not logged in
  if (!req.user) {
    res.render("loginError");
  } 
  // bad accidental next call!! Will call next after rendering login error
  next();
});

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