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2023-04-10 08:00:04

错误:发送到客户端后无法设置标头

我对Node.js相当陌生，我有一些问题。

我使用的是Node.js 4.10和Express 2.4.3。

当我尝试访问http://127.0.0.1:8888/auth/facebook时，我将被重定向到http://127.0.0.1:8888/auth/facebook_callback。

然后我收到以下错误:

Error: Can't render headers after they are sent to the client.
    at ServerResponse.<anonymous> (http.js:573:11)
    at ServerResponse._renderHeaders (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:64:25)
    at ServerResponse.writeHead (http.js:813:20)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/auth.strategies/facebook.js:28:15
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:113:13
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/strategyExecutor.js:45:39)
    at [object Object].pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:32:3)
    at [object Object].halt (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:29:8)
    at [object Object].redirect (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/authExecutionScope.js:16:8)
    at [object Object].<anonymous> (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/auth.strategies/facebook.js:77:15)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:195:11)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at param (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:189:13)
    at pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:191:10)
    at Object.router [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:197:6)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at param (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:189:13)
    at pass (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:191:10)
    at Object.router [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/router.js:197:6)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at Object.auth [as handle] (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect-auth/lib/index.js:153:7)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at HTTPServer.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:211:3)
    at Object.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:105:14)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:150:23)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at HTTPServer.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:211:3)
    at Object.handle (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:105:14)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:198:15)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:323:9
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:338:9

node.js:134
        throw e; // process.nextTick error, or 'error' event on first tick
        ^
Error: Can't set headers after they are sent.
    at ServerResponse.<anonymous> (http.js:527:11)
    at ServerResponse.setHeader (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/patch.js:50:20)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:162:13)
    at next (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/http.js:207:9)
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:323:9
    at /home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session.js:338:9
    at Array.<anonymous> (/home/eugene/public_html/all_things_node/projects/fb2/node_modules/connect/lib/middleware/session/memory.js:57:7)
    at EventEmitter._tickCallback (node.js:126:26)

以下是我的代码:

var fbId= "XXX";
var fbSecret= "XXXXXX";
var fbCallbackAddress= "http://127.0.0.1:8888/auth/facebook_callback"

var cookieSecret = "node";     // enter a random hash for security

var express= require('express');
var auth = require('connect-auth')
var app = express.createServer();


app.configure(function(){
    app.use(express.bodyParser());
    app.use(express.methodOverride());
    app.use(express.cookieParser());
    app.use(express.session({secret: cookieSecret}));
    app.use(auth([
        auth.Facebook({
            appId : fbId,
            appSecret: fbSecret,
            callback: fbCallbackAddress,
            scope: 'offline_access,email,user_about_me,user_activities,manage_pages,publish_stream',
            failedUri: '/noauth'
        })
    ]));
    app.use(app.router);
});


app.get('/auth/facebook', function(req, res) {
  req.authenticate("facebook", function(error, authenticated) {
    if (authenticated) {
      res.redirect("/great");
      console.log("ok cool.");
      console.log(res['req']['session']);
    }
  });
});

app.get('/noauth', function(req, res) {
  console.log('Authentication Failed');
  res.send('Authentication Failed');
});

app.get('/great', function( req, res) {
  res.send('Supercoolstuff');
});

app.listen(8888);

我可以知道我的代码有什么问题吗?

当前回答

对于任何遇到这种情况的人来说，其他解决方案都没有帮助，在我的情况下，这在处理图像上传但不处理超时的路由上表现出来，因此，如果上传花费了太长时间并超时，当回调在超时响应发送后被触发时，调用res.send()会导致崩溃，因为报头已经设置为考虑超时。

这很容易通过设置一个非常短的超时和撞击路线与一个相当大的图像再现，每次崩溃都被再现。

2015-05-19 12:56:11

其他回答

有一段时间我也遇到了这个错误。我想(希望)我已经想明白了，想把它写在这里供参考。

当你使用app.use方法添加中间件来连接或表达(建立在connect上)时，你在connect中将项目附加到Server.prototype.stack中(至少在当前的npm install connect中，它看起来与本文的github有很大不同)。当服务器收到请求时，它遍历堆栈，调用(request, response, next)方法。

问题是，如果在一个中间件项目中写入响应体或报头(出于某种原因，它看起来像是/或)，但没有调用response.end()，而是调用next()，然后作为核心Server.prototype.handle方法完成，它将注意到:

堆栈中没有更多的项，和/或 这种反应。headerSent为true。

因此，它抛出一个错误。但是它抛出的错误只是这个基本的响应(来自connect http.js源代码:

res.statusCode = 404;
res.setHeader('Content-Type', 'text/plain');
res.end('Cannot ' + req.method + ' ' + req.url);

就在那里，它调用res.setHeader('Content-Type'， 'text/plain');，你可能已经在你的渲染方法中设置了，而没有调用response.end()，类似于:

response.setHeader("Content-Type", "text/html");
response.write("<p>Hello World</p>");

所有东西的结构是这样的:

良好的中间件

// middleware that does not modify the response body
var doesNotModifyBody = function(request, response, next) {
  request.params = {
    a: "b"
  };
  // calls next because it hasn't modified the header
  next();
};

// middleware that modify the response body
var doesModifyBody = function(request, response, next) {
  response.setHeader("Content-Type", "text/html");
  response.write("<p>Hello World</p>");
  response.end();
  // doesn't call next()
};

app.use(doesNotModifyBody);
app.use(doesModifyBody);

有问题的中间件

var problemMiddleware = function(request, response, next) {
  response.setHeader("Content-Type", "text/html");
  response.write("<p>Hello World</p>");
  next();
};

有问题的中间件设置响应头时没有调用response.end()，而是调用next()，这会混淆connect的服务器。

2011-10-17 03:38:10

请检查您的代码是否为单个请求返回多个res.send()语句。就像当我有这个问题....

我在我的restify节点应用程序中遇到了这个问题。错误在于

switch (status) {
    case -1:
      res.send(400);
    case 0:
      res.send(200);
    default:
      res.send(500);
}

我在不间断的情况下使用开关处理各种情况。对于那些稍微熟悉开关情况的人都知道，不间断，返回关键字。case下的代码和它的下一行都将被执行。虽然我想发送单个res。send，但由于这个错误它返回了多个res。send语句，这提示

错误:不能设置头后，他们被发送到客户端。

通过添加这个或在每个res.send()方法之前使用return来解决，比如return res.send(200)

switch (status) {
    case -1:
      res.send(400);
      break;
    case 0:
      res.send(200);
      break;
    default:
      res.send(500);
      break;
}
2019-01-12 06:13:09

Express中的res对象是Node.js的http的子类。ServerResponse(读取http.js源代码)。你可以调用res.setHeader(name, value)，直到你调用res.writeHead(statusCode)。在writeHead之后，头被烘焙进去，你只能调用res.write(data)，最后调用res.end(data)。

错误“错误:发送后无法设置报头”意味着您已经处于Body或Finished状态，但某些函数试图设置报头或statusCode。当您看到此错误时，请尝试查找在已经写入部分正文之后试图发送头的任何内容。例如，查找意外调用两次的回调，或者在正文发送之后发生的任何错误。

在您的示例中，您调用了res.redirect()，这导致响应变为Finished。然后你的代码抛出一个错误(res.req是null)。并且由于错误发生在您的实际函数(req, res, next)(而不是回调函数)中，Connect能够捕获它，然后尝试发送一个500错误页面。但是由于头已经发送，Node.js的setHeader抛出了你所看到的错误。

Node.js/Express响应方法的综合列表，以及何时必须调用它们:

响应必须在头部，并保持在头部:

res.writeContinue () res.statusCode = 404 res.setHeader(名称、值) res.getHeader(名字) res.removeHeader(名字) res.header(key[， val]) res.charset = 'utf-8'(仅限Express;只影响特定于express的方法) res.contentType(类型)(仅适用于Express)

Response必须在Head中并成为Body:

作家(雕像，[原因]，[标题])

Response可以在Head/Body中任意一个，并保留在Body中:

res.write (chunk, encoding =‘utf8)

Response可以在Head/Body中任意一个，变成Finished:

res.end((数据),(编码))

响应可以在Head/Body中任意一个，并保持当前状态:

res.addTrailers(头)

响应必须在头部，成为完成:

return next([err]) (Connect/Express only) Any exceptions within middleware function(req, res, next) (Connect/Express only) res.send(body|status[, headers|status[, status]]) (Express only) res.attachment(filename) (Express only) res.sendfile(path[, options[, callback]]) (Express only) res.json(obj[, headers|status[, status]]) (Express only) res.redirect(url[, status]) (Express only) res.cookie(name, val[, options]) (Express only) res.clearCookie(name[, options]) (Express only) res.render(view[, options[, fn]]) (Express only) res.partial(view[, options]) (Express only)

2011-08-17 00:11:24

In my case, this is recurring when I don't make a function that is running against a mongodb schema an async function like this technicianAuthSchema.methods.matchPasswords = function(password) { return await bcrypt.compare( password, this.password ); }; I get this Logged error: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client instead of technicianAuthSchema.methods.matchPasswords = async function(password) { return await bcrypt.compare( password, this.password ); }; It is asynchronous because the this.password is coming from the object this function is running against which we are pulling from the database.

2021-04-22 09:46:24

检查代码。对我来说，我在同一个if语句中两次使用res.status。第一个设置了报头状态，第二个试图改变它，这导致了问题。

2021-05-01 08:45:43

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